NZ626382B2 - Apparatus for controlling fluid flow - Google Patents
Apparatus for controlling fluid flow Download PDFInfo
- Publication number
- NZ626382B2 NZ626382B2 NZ626382A NZ62638212A NZ626382B2 NZ 626382 B2 NZ626382 B2 NZ 626382B2 NZ 626382 A NZ626382 A NZ 626382A NZ 62638212 A NZ62638212 A NZ 62638212A NZ 626382 B2 NZ626382 B2 NZ 626382B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- image
- fluid
- processor
- valve
- support member
- Prior art date
Links
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Classifications
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- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/168—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body
- A61M5/16886—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body for measuring fluid flow rate, i.e. flowmeters
- A61M5/1689—Drip counters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/168—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body
- A61M5/172—Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body electrical or electronic
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2270/00—Control; Monitoring or safety arrangements
- F04C2270/04—Force
- F04C2270/041—Controlled or regulated
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/026—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring distance between sensor and object
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/661—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters using light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
- G01F15/02—Compensating or correcting for variations in pressure, density or temperature
- G01F15/028—Compensating or correcting for variations in pressure, density or temperature for low flow rates
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F22/00—Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
- G06Q50/10—Services
- G06Q50/22—Social work
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
- G06T7/0012—Biomedical image inspection
-
- G—PHYSICS
- G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
- G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- G16H20/00—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
- G16H20/10—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance relating to drugs or medications, e.g. for ensuring correct administration to patients
- G16H20/17—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance relating to drugs or medications, e.g. for ensuring correct administration to patients delivered via infusion or injection
-
- G—PHYSICS
- G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
- G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- G16H40/00—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices
- G16H40/40—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades
Abstract
apparatus (1), system and method for regulating fluid flow in an intravenous drip are disclosed. The apparatus holds a drip chamber (4) in relation to an imaging device (11, 19, 18, 20). Images are captured of a drop forming in the drip chamber (4) and the volumetric growth of the drip is estimated. The estimated flow rate into the drip chamber (4) is then used to generate an error signal to control a valve actuator (6) with a closed loop control system (14). ed. The estimated flow rate into the drip chamber (4) is then used to generate an error signal to control a valve actuator (6) with a closed loop control system (14).
Description
APPARATUS FOR CONTROLLING FLUID FLOW
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a Non-Provisional, International ation filed
under the Patent Cooperation Treaty which claims priority to and the benefit of the
following:
U.S. Provisional Patent Application Serial No. 61/578,649, filed December
21, 2011 and entitled System, Method, and Apparatus for Infusing Fluid
(Attorney Docket No. J02);
U.S. Provisional Patent Application Serial No. 61/578,658, filed December
21, 2011 and entitled System, Method, and Apparatus for Estimating Liquid
Delivery ney Docket No. J04);
U.S. Provisional Patent Application Serial No. ,674, filed December
21, 2011 and ed System, Method, and Apparatus for Dispensing Oral
Medications (Attorney Docket No. J05);
U.S. Provisional Patent Application Serial No. 61/651,322, filed May 24,
2012 and entitled System, Method, and tus for Electronic t Care
(Attorney Docket No. J46); and
U.S. Provisional Patent Application Serial No. 61/679,117, filed August 3,
2012 and entitled System, Method, and tus for Monitoring, Regulating,
or Controlling Fluid Flow (Attorney Docket No. J30), each of which is hereby
incorporated herein by reference in its entirety.
This application claims priority to, benefit of, and is also a Continuation-In-
Part ation of the following:
U.S. Patent Application Serial Number 13/333,574, filed December 21, 2011
and entitled System, Method, and Apparatus for Electronic Patient Care, now
U.S. ation No. US0185267-A1, published July 19, 2012 (Attorney
Docket No. I97), and
PCT Application Serial No. PCT/US11/66588, filed December 21, 2011 and
entitled System, , and Apparatus for Electronic Patient Care (Attorney
Docket No. I97WO), both of which are hereby incorporated herein by reference in
their entireties.
This application may also be related to one or more of the ing patent
applications filed on even date herewith, all of which are hereby incorporated herein
by reference in their entireties:
Nonprovisional application for System, , and Apparatus for
Clamping (Attorney Docket No. J47);
Nonprovisional application for , Method, and Apparatus for
Dispensing Oral Medications Attorney Docket No. J74);
PCT application for System, Method, and Apparatus for Dispensing Oral
Medications Attorney Docket No. J74WO);
Nonprovisional application for System, , and Apparatus for
Estimating Liquid Delivery ney Docket No. J75);
visional application for System, Method, and Apparatus for
Infusing Fluid (Attorney Doceket No. J76);
PCT application for System, , and Apparatus for Infusing Fluid
(Attorney Docket No. J76WO);
Nonprovisional application for System, Method, and Apparatus for
onic Patient Care (Attorney Docket No. J77);
Nonprovisional application for System, Method, and tus for
Electronic Patient Care (Attorney Docket No. J78);
Nonprovisional application for System, Method, and Apparatus for
Monitoring, Regulating, or Controlling Fluid Flow (Attorney Docket No. J79);
Nonprovisional application for System, Method, and Apparatus for
Estimating Liquid Delivery (Attorney Docket No. J81);
PCT application for System, Method, and Apparatus for Estimating
Liquid Delivery (Attorney Docket No. J81WO); and
Nonprovisional application for System, Method, and Apparatus for
Electronic Patient Care (Attorney Docket No. J85).
BACKGROUND
Relevant Field
The present disclosure relates to monitoring, regulating, or controlling fluid
flow. More particularly, the present disclosure s to a system, method, and
apparatus for monitoring, regulating, or controlling fluid flow, for example, for use in
medical applications such as enous infusion y, dialysis, transfusion
therapy, peritoneal infusion therapy, bolus delivery, enteral nutrition therapy,
parenteral nutrition y, hemoperfusion therapy, fluid itation therapy, or
insulin delivery, among others.
Description of Related Art
|n many medical settings, one common mode of medical treatment involves
delivering fluids into a patient, such as a human, animal, or pet. The need may
arise to rapidly infuse fluid into the t, accurately infuse the fluid into the
patient, and/or slowly infuse the fluid into the patient. Saline and lactated ringers
are examples of commonly used fluids. Such fluids may be used to maintain or
elevate blood re and promote adequate perfusion. In the shock-trauma
setting or in septic shock, fluid resuscitation is often a first-line therapy to maintain
or e blood pressure.
Delivery of fluid into the patient may be facilitated by use of a gravity-fed line
(or tube) inserted into the patient. Typically, a fluid reservoir (e.g., an IV bag) is
hung on a pole and is ted to the fluid tube. The fluid tube is sometimes
coupled to a drip chamber for trapping air and estimating fluid flow. Below the fluid
tube may be a manually actuated valve used to adjust the flow of fluid. For
example, by counting the number of drops formed in the drip chamber within a
certain amount of time, a ver can calculate the rate of fluid that flows through
the drip chamber and adjust the valve (if needed) to achieve a desired flow rate.
n treatments require that the fluid delivery system strictly adhere to the
flow rate set by the caregiver. Typically, such applications use an infusion pump,
but such pumps may not be used in all ions or environments.
Briefly, and in general terms, the present disclosure relates to a system,
method, and apparatus for monitoring, regulating, or controlling fluid flow, for
example, for use in medical applications such as intravenous infusion therapy,
2012/071142
dialysis, transfusion therapy, peritoneal infusion therapy, bolus delivery, enteral
nutrition therapy, parenteral nutrition therapy, hemoperfusion therapy, fluid
resuscitation therapy, or insulin delivery, among others. More particularly, the
present disclosure relates to a fluid flow meter for monitoring the flow of fluids
associated with a patient, a valve for regulating the flow of fluid associated with the
patient, and/or a fluid flow meter coupled to a valve (e.g., arranged in a closed-loop,
open-loop, or feedback configuration) to monitor, regulate and/or control the use of
fluid associated with the patient.
|n some embodiments of the present disclosure, a flow meter includes one
or more optical sensors to r the flow of fluid within a tube, for example, using
an image sensor to monitor drops within a drip chamber attached to the tube. The
flow meter may be a stand-alone device, may be used in conjunction with either a
pump or a valve, or both, and/or may be used to provide feedback to any electronic
. The flow meter may be remotely controlled, e.g., by a monitoring client, a
remote communicator, a smart phone, a computer, etc. The flow meter may
e the average flow rate, an taneous flow rate, a drop volume, a drop
growth rate, or other parameter related to fluid flow.
The flow meter may use the flow rate or parameter related to fluid flow to: (1)
y the flow rate or parameter on a screen, (2) provide feedback, such as the
flow rate or parameter related to fluid flow (wirelessly or via wires), to an infusion
pump such as a peristaltic pump, (3) provide feedback to a monitoring client or
remote monitoring client such as a smart phone, (4) issue alarms when the flow
rate or parameter related to fluid flow is outside a predetermined range, (5) issue an
alarm with the flow rate or ter related to fluid flow is above a predetermined
threshold, (6) issue an alarm with a free flow is detected, (7) communicate alarms
to a pump, a monitoring client, or a remote monitoring , (8), instruct a valve to
stop fluid flow when a free flow is detected, an alarm is issued, and/or the flow rate
or ter related to fluid flow is above a threshold or is outside of a
predetermined range, and/or (9) broadcast the flow rate or ter d to
fluid flow.
|n some embodiments described herein, a valve regulates the flow of fluid
associated with a patient. The valves disclosed herein may be manually ed
or may be actuated with an actuator (or both). The valve may be used with or
without a pump, with or without a flow meter, and/or may be a standalone device.
2012/071142
The valve may be remotely controlled, e.g., by a monitoring client, a remote
communicator, a smart phone, a computer, etc. The valve may compress a tube
along a portion that is substantially greater than the diameter of the tube, e.g., 2
times greater, 5 times greater, 10 times greater, etc.
The valve may be made of two or more pieces that compress the tube or
may be made of a single piece that compresses the tube as the piece is moved or
deformed. The two or more pieces and/or the single piece may be made using
injection molding, ultrasonic welding, using multiple pieces that are glued or molded
together, or the like. Each of the two or more pieces may be made by one or more
subparts that are attachable to each other either permanently or temporarily. The
single piece may be made by one or more subparts that are coupled er either
permanently or temporarily, e.g., using ultrasonic welding, , latching, or other
technique. The pieces may be plastic, metal, an alloy, a polymer, or other material.
In some embodiments of the present disclosure, a flow meter is coupled to a
valve to regulate fluid flow, e.g., fluid flow into a patient. The flow meter coupled to
the valve may be used in lieu of a pump, such as a peristaltic infusion pump, or
may be a replacement for an infusion pump. The flow meter and valve combination
may be remotely controlled, e.g., by a monitoring , a remote communicator, a
smart phone, a computer, etc. or may be remotely monitored. A monitoring client
may control the flow meter or valve, may be a relay between the flow meter and
valve, may monitor the operation of the flow meter or valve, may communicate
ation related to the flow meter or valve to a server, and/or may not be used in
the system.
The flow meter may monitor the flow of fluid and make adjustments, ly
or indirectly, to a valve or a pump (e.g., an on pump). The flow meter may
alarm when it detects free flow conditions, determines if the flow rate is greater a
predetermined threshold or is outside a predetermined range, and/or detects any
al behavior. The flow meter, in response to an alarm or condition, may
cause the flow meter to stop fluid flow, instruct a valve to stop fluid flow, instruct a
safety valve to stop fluid flow, notify a monitoring client or remote communicator,
broadcast the detected ion, or perform a predefine e or algorithm.
|n certain ments of the present sure, an apparatus for
regulating fluid flow includes a curved, elongated support member and an opposing
support member. The curved, elongated support member is elastically deformable
and has first and second ends. The opposing support member is configured to
position a tube against the curved, elongated support member between the first
and second ends such that deformation of the curved, elongated support member
by movement of the first and second ends toward each other reduces an al
volume of the tube. The opposing support member may be another curved,
elongated support member.
The apparatus may include an actuator coupled to the curved, elongated
support member to deform the , elongated support member by nt of
the first and second ends toward each other by actuation of the actuator. In some
such embodiments, the actuator may be a lead screw, and a knob may be coupled
to the lead screw to actuate the lead screw.
The or, the curved, elongated t member, and the opposing
support member may be configured to regulate the fluid flow by actuation of the
actuator in accordance with a Gompertz curve. The actuator may be further
configured, in some embodiments, to actuate the first and second ends toward
each other along a predetermined portion of the Gompertz curve. For example, the
actuator may only actuate the actuator along a portion of the actuatable range of
the curved, elongated t member and the ng support member.
The or, the curved, elongated support member, and the opposing
support member may be configured to regulate the fluid flow by actuation of the
actuator in accordance with a d curve. The actuator may be further
configured to actuate the first and second ends toward each other along a
predetermined n of the sigmoid curve.
The curved, elongated t member may be semi-rigid and/or may
consist essentially of a hable al. The curved, elongated support
member may be an arcuate, elongated support member, and/or may be C-shaped.
The apparatus may further comprise an elongated connecting member
operatively coupled to the first and second ends of the curved, elongated support
member.
[0018]|n certain embodiments of the present disclosure, the apparatus may
comprise an actuator coupled to the elongated connecting member and the curved,
elongated support member to apply an d expanding force to thereby deform
the first and second ends of the curved, elongated support members toward each
other.
|n certain embodiments of the present disclosure, the , elongated
support member is disposed about parallel to the another curved, elongated
support member along a substantial portion f. For example, the curved,
elongated t member defines a length, and the another curved, elongated
support member defines a length and the length of the another curved, elongated
support member is disposed approximately parallel with the length of the curved,
elongated t member.
In certain embodiments of the present disclosure, the apparatus includes an
actuator operatively coupled to the curved, elongated support member at the first
and second ends, and to the another curved, elongated support member at first
and second ends. The actuation of the actuator causes the first and second ends
of the curved, elongated support member to approach each other and also causes
the first and second ends of the another curved, elongated support member to
approach each other to thereby cause a reduction in distance between the curved,
elongated support member and the another curved, ted support member to
thereby compress the tube.
|n n embodiments of the present disclosure, the curved, elongated
t member defines a length, and the opposing t member is disposed
orthogonally from the length along a n thereof.
[0022]|n certain embodiments of the present disclosure, the curved, elongated
support member includes a plurality of ridges disposed thereon to engage the tube.
|n n embodiments of the present disclosure, the opposing support
member includes a plurality of ridges ed thereon configured to engage the
tube.
[0024]|n n embodiments of the present disclosure, the curved, elongated
support member includes a flange ing from a length thereof configured to
hold the tube. The opposing support member may include another flange
extending from a length thereof configured to hold the tube such that the flange and
the another flange are about parallel to each other and are about parallel to a
central axis defined by the tube when the tube is ed therebetween.
|n certain embodiments of the present disclosure, an apparatus for
regulating fluid flow includes a first ted t member, a second elongated
support member, and an actuator. The first elongated support member defines a
length, and the second elongated support member also defines its own length such
that the length of the second elongated support member is disposed in spaced
relation with the length of the first elongated support member to cooperate with the
first elongated support member to compress a tube. The actuator is in mechanical
ment with at least one of the first and second elongated t s
to actuate the first and second elongated support members toward each other to
thereby compress a tube disposed therebetween to regulate flow of fluid within the
tube such that actuation of the actuator actuates the first and second elongated
support members to regulate fluid flow within the tube in accordance with an
approximate d curve.
[0026]The length of the second elongated support member may be disposed about
parallel to the length of the first elongated support member. The first and second
elongated support members may be configured to cooperate with each other to
compress the tube along a length of the tube at least substantially greater than the
diameter of the tube. The actuator may be configured to actuate the first and
second elongated support members to compress the tube to regulate fluid flow
within the tube along a predetermined portion of the sigmoid curve.
|n certain embodiments of the t disclosure, an apparatus for
regulating fluid flow es first and second elongated support members. The first
elongated support member defines a length and the second ted support
member defines a length. The length of the second elongated support member is
disposed in spaced relation with the length of the first elongated support member to
cooperate with the first ted support member to compress a tube. The
actuator is in mechanical engagement with at least one of the first and second
elongated support members to actuate the first and second elongated support
members toward each other to thereby compress a tube disposed therebetween to
regulate flow of fluid within the tube such that actuation of the or actuates the
first and second elongated support members to regulate fluid flow within the tube in
accordance with an imate Gompertz curve.
The length of the second ted support member may be disposed about
parallel to the length of the first elongated support member. The first and second
ted support members may be configured to cooperate with each other to
compress the tube along a length at least substantially greater than the diameter of
the tube.
The actuator may be configured to actuate the first and second elongated
support members to compress the tube to te fluid flow within the tube in
accordance with a predetermined portion of the Gompertz curve.
|n certain embodiments of the present disclosure, an apparatus for
ting fluid flow es first and second elongated support members. The first
elongated support member defines a length, and the second elongated support
member defines a length such that the length of the second elongated support
member is disposed in spaced relation with the length of the first elongated support
member to cooperate with the first elongated support member to compress a tube.
The actuator is in mechanical engagement with at least one of the first and second
elongated support members to actuate the first and second elongated support
members toward each other to thereby ss a tube disposed etween to
regulate flow of fluid within the tube such that actuation of the actuator actuates the
first and second elongated support members to regulate fluid flow within the tube in
accordance with an approximate generalized logistic function.
The length of the second ted support member may be disposed about
parallel to the length of the first elongated support member. The first and second
elongated support members may be configured to cooperate with each other to
compress the tube along a length of the tube at least substantially greater than the
diameter of the tube. The actuator may be further configured to actuate the first
and second elongated support s to compress the tube to regulate fluid flow
within the tube in accordance with a predetermined portion of the generalized
logistic function.
|n certain embodiments of the present disclosure, an apparatus for
regulating fluid flow includes first and second support members, and an actuator.
The first t member forms at least one of an arc, a ity of arcs, a curve, a
plurality of curves, an arcuate shape, a plurality of arcuate , an S—shape, a
C-shape, a convex shape, a ity of convex , a concave shape, and a
plurality of convex shapes. The second support member is ed in spaced
relation with the first support member to ate with the first support member to
compress a tube along a length of the tube at least substantially greater than the
diameter of the tube. The actuator is in mechanical engagement with at least one
of the first and second support members to actuate the first and second support
members toward each other to thereby compress a tube disposed therebetween to
regulate flow of fluid within the tube such that ion of the actuator actuates the
first and second support members to regulate fluid flow within the tube in
accordance with an approximate nonlinear function.
The approximate nonlinear function may be an approximate generalized
logistic on, an approximate sigmoid curve, and/or an approximate tz
curve. The actuator may be configured to actuate to thereby regulate the fluid flow
within the tube in accordance with a predetermined portion of the imate
ear function.
|n certain embodiments of the present disclosure, the first support member
forms an arc, has a shape consisting essentially of an arc, forms a plurality of arcs,
has a shape consisting essentially of a plurality of arcs, forms a curve, has a shape
consisting essentially of a curve, forms a plurality of curves, has a shape consisting
essentially of a plurality of curves, forms an arcuate shape, has a shape consisting
essentially of an arcuate shape, forms a plurality of arcuate shapes, has a shape
consisting essentially of a plurality of arcuate shapes, forms an S—shape, has a
shape consisting ially of an S—shape, forms the e, has a shape
consisting essentially of a C-shape, forms a convex shape, has a shape consisting
essentially of a convex shape, forms a plurality of convex shapes, has a shape
consisting essentially of a ity of convex shapes, forms a concave shape, has a
shape ting essentially of a concave shape, forms a plurality of e
shapes, and/or has a shape consisting essentially of a plurality of concave shapes.
A length of the second support member may be disposed about parallel to a
length of the first support member. The first and second support members may be
configured to cooperate with each other to compress the tube along a length of the
tube at least ntially greater than the diameter of the tube.
|n certain embodiments of the t sure, an apparatus for
regulating fluid flow includes a curved, elongated support member and an opposing
support member. The curved, elongated support member is elastically deformable
and has first and second ends. The opposing support member is configured to
define a conduit with the curved, elongated support member such that the conduit
is defined between the curved, ted support member and the opposing
member; Deformation of the curved, elongated support member by movement of
the first and second ends toward each other reduces an internal volume of the
conduit. In some embodiments, the conduit may be configured to receive a tube.
In yet additional embodiments, the conduit is fluidly sealed, and the apparatus
further comprises first and second ports in fluid communication with the conduit
such that each port is d for being coupled to a tube.
|n n embodiments of the t disclosure, a system for regulating
fluid flow es a flexible tube and an inverse-Bourdon-tube valve. The flexible
fluid tube has a fluid path and is configured for passing fluid therethrough. The
inverse-Bourdon-tube valve is coupled to the flexible fluid tube to regulate the fluid
flowing through the fluid path of the le fluid tube. An actuator may be coupled
to the inverse-Bourdon-tube valve to actuate the inverse-Bourdon-tube valve to
te the fluid flowing through the fluid path of the flexible fluid tube. An inverse-
n-tube valve works in an opposite way of a Bourdon tube in that a
deformation of the fluid path causes changes in fluid flow rather than fluid flow
causing deformation of the fluid path.
|n certain embodiments of the t disclosure, a system for regulating
fluid flow includes a fluid tube, a valve, and an actuator. The fluid tube defines a
fluid path configured for passing fluid therethrough. The valve is operatively
coupled to the fluid tube and includes first and second flexible s. The
second flexible member is operatively coupled to the first flexible member. The
fluid tube is disposed between the first and second flexible members, and the first
and second flexible members are configured to flex to thereby regulate flow of fluid
passing h the fluid tube. The actuator is coupled to at least a first end of the
first flexible member and a second end of the first flexible . The actuator
may be a lead screw and there may be an electrically powered motor coupled to
the lead screw to turn the lead screw.
[0039]|n certain embodiments of the present disclosure, the system may include a
knob coupled to the lead screw such that the knob is configured to rotate the lead
screw. The knob may be engaged by a motor-driven actuator.
In certain embodiments of the present disclosure, the actuator is coupled to
a first end of the first flexible member and a second end of the first flexible member,
and the actuator is configured to at least one of flex the first and second ends
toward each other and flex the first and second ends away from each other. The
actuator may flex the first and second ends away from each other and/or the
actuator flexes the first and second flexible members such that the first and second
ends approach each other. The first and second flexible members may be
generally rectangular. The first member and/or the second member may be
tensioned to at least substantially stop fluid flow when the actuator ceases
application of a force.
The system may include a flow meter coupled to a drip chamber that is
coupled to the fluid tube such that the flow meter estimates fluid flow through the
drip chamber and therefore also estimate fluid flow h the fluid tube. The flow
meter may be an image-sensor-based, flow meter.
The flow meter may be operatively coupled to a motor to e the valve,
and the system may include a control component to control the motor to actuate the
valve to achieve a desired flow rate as estimated by the flow meter.
|n certain embodiments of the present disclosure, an apparatus for
regulating fluid flow includes first and second C-shaped members. The first C-
shaped member s inner and outer surfaces, and the second C-shaped
member defines inner and outer surfaces. At least one of the outer surface of the
first C-shaped member and the inner surface of the second C-shaped member is
configured to receive a tube. The inner surface of the second C-shaped member is
disposed in spaced relation to the outer surface of the first C-shaped member. A
substantial area of the inner surface of the second C-shaped member may, in some
specific embodiments, abut the outer surface of the first ed member.
[0044]ln certain embodiments of the present disclosure, the second C-shaped
member is flexible and the first C-shaped member is igid, is rigid, and/or is an
elastomer.
A flexible member may be formed from a material selected from the group
consisting of a c, a polymer, a monomer, a opylene, a thermoplastic
polymer, a ceramic, a polyvinyl chloride, and a hylene.
|n certain embodiments of the present disclosure, an apparatus for
regulating fluid flow includes first and second flexible sheets. The second flexible
sheet is operatively coupled to the first flexible sheet. The first and second flexible
sheets are configured to receive a fluid tube etween, and the first and second
flexible sheets are also configured to flex to y regulate flow of fluid passing
through the fluid tube.
The apparatus may include an actuator coupled to a first end of the first
flexible sheet and a second end of the first flexible sheet. The actuator may be
WO 96722
configured to at least one of flex the first and second ends toward each other and
flex the first and second ends away from each other.
The apparatus may include a lead screw coupled to a first end of the first
flexible sheet and a second end of the first flexible sheet, and a knob coupled to the
lead screw such that rotation of the knob rotates the lead screw. The knob may be
ured for engagement with a motor-driven actuator whereby the motor-driven
or actuates the knob.
|n certain embodiments of the present disclosure, an apparatus for
ting fluid flow includes first and second curve-shaped members. The first
curve-shaped member defines inner and outer surfaces, and the second curve-
shaped member also defines inner and outer surfaces. The inner surface of the
second curve-shaped member is disposed in spaced relation to the outer surface of
the first curve-shaped member.
At least one of the first and second curve-shaped members may be
ured to position a fluid tube therebetween. The first curve-shaped member
may be at least one of semi-rigid and rigid. The second curve-shaped member
may be flexible. The second curve-shaped member may comprise an elastomer.
The first and second curve-shaped members may be flexible.
The apparatus may comprise a connecting member operatively coupled to at
least one of a first end of the first curve-shaped member and a first end of the
second curve-shaped member such that the connecting member is also ively
coupled to at least one of a second end of the first curve-shaped member and a
second end of the second curve-shaped member. The connecting member may be
flexible, may be rigid, and/or may be semi-rigid.
[0052]The apparatus may include an actuator oned between the connecting
member and the second curve-shaped member to apply a force therebetween
when actuated. The actuator may be a lead screw.
|n certain ments of the present disclosure, an tus for
regulating fluid flow includes first and second curve-shaped members. The first
curve-shaped member defines inner and outer surfaces. The first curve-shaped
member has first and second receiving members at te ends of the first curve-
shaped member. The second curve-shaped member s inner and outer
surfaces. The second curve-shaped member has first and second fasteners at
opposite ends of the second curve-shaped member. At least one of the first and
WO 96722
second fasteners may be a hook. The first ing member of the first curve-
shaped member is configured to engage the first fastener of the second curve-
shaped member, and the second receiving member of the first curve-shaped
member is configured to engage the second fastener of the second curve-shaped
member.
At least one of the receiving members may be a cylindrically-shaped
member, such as a barrel nut, ured for coupling to a hook.
At least one of the receiving members may be operatively coupled to an
actuator. One or more of the receiving members may be operatively coupled to an
electric motor.
|n certain ments of the present disclosure, the apparatus further
includes an electric motor coupled to the first receiving member such that: (1) the
electric motor turns a rotor coupled to a shaft having threads on an outer surface
thereof; (2) the second receiving member defines a threaded hole configured to
receive the shaft; and (3) the threaded hole and shaft cooperate together to at least
one of increase or decrease the distance between the first and second receiving
members when the electric motor rotates the rotor to thereby rotate the shaft.
|n certain embodiments of the present disclosure, an apparatus for
regulating fluid flow includes first and second curved, elongated support members.
The first curved, elongated support member is elastically deformable and has first
and second ends. The second curved, elongated support member is elastically
deformable and has first and second ends. The second curved, elongated support
member is configured to position a tube against the first , ted support
such that deformation of the first and second curved, elongated support members
by movement of the first and second ends of the first , elongated support
member toward each other s an internal volume of the tube.
The first connector is coupled to the first end of the first curved, elongated
support member and is also coupled to the first end of the second curved,
elongated t . The second connector is coupled to the second end of
the first curved, elongated support member and is also coupled to the second end
of the second curved, ted support member. The second connector defines a
hole. The connecting member has an end coupled to the first connector and
another end configured for insertion into the hole of the second connector. The
connecting member s a threaded rod at least along a portion thereof. The
knob has a ratchet configured to ratchet onto the connector member when moved
from the another end of the connecting member toward the end of the connector
member. The knob is further configured to engage the threaded rod of the
ting member. The knob may include a plurality of fingers configured to
engage the threaded rod of the connecting member. The knob defines an outer
periphery and includes a hole defined at the center of the outer periphery of the
knob. The hole is configured to receive the threaded rod. The plurality of fingers
each arc to engage the threaded rod at a respective end of each of the plurality of
fingers.
[0059]The first curved, elongated support member defines a first hole adjacent to
the first end of the first curved, elongated support member. The hole is configured
to hold a fluid tube.
The first , elongated support member may define a first notch
adjacent to the first end of the first curved, elongated support member such that the
notch is configured to receive a fluid tube. The notch may include a neck
configured to receive the fluid tube and a circular region configured to retain the
fluid tube.
|n certain embodiments of the present disclosure, an apparatus for
ting fluid flow includes a base, a plurality of s, and a ring. The base
defines a hole ured to receive a fluid tube. The plurality of fingers each has
an end coupled to the base. The ring is configured to slide from the base and
along the plurality of fingers. nt of the ring away from the base and toward
the fingers sses the fingers against the tube. The ring is configured to
frictionally lock against the plurality of s. Each finger includes an elongated
end coupled to the base and a curved end coupled to an te end relative to
the base.
|n certain embodiments of the present disclosure, an apparatus for
regulating fluid flow includes a conically-shaped member, a complementing
member, and an actuator. The conically-shaped member has a surface for
wrapping a tube therearound. The menting member is configured to
engage the conically-shaped member for compressing the tube. The actuator is
configured to compress the conically-shaped member against the complementing
member to thereby compress the tube.
|n certain ments of the present disclosure, an intravenous
administration set includes: a flexible tube for directing fluid flow therewithin;
a first port at a first end of the flexible tube; a second port a second end of the
le tube; a curved, elongated support member elastically deformable and
having first and second ends; and an opposing t member configured to
position the flexible tube against the curved, elongated support member between
the first and second ends such that deformation of the curved, elongated support
member by movement of the first and second ends toward each other reduces an
internal volume of the tube.
[0064]The intravenous stration set may further include a drip chamber
coupled to the le tube, another port configured to receive a syringe for
injection of fluid into the fluid flow within the flexible tube, and/or a slide occluder
coupled to the flexible tube configured to engage the flexible tube to e fluid
flow therewithin.
[0065]The first end of the curved, elongated t member may define a first
hole to receive the flexible tube, and the second end of the curved, elongated
support member may define a second hole to receive the flexible tube.
|n certain embodiments of the present disclosure, a flow meter includes a
coupler, a support member, first and second image s, and at least one
processor. The coupler is adapted to couple to a drip chamber. The support
member is operatively coupled to the r. The first image sensor has a first
field of view and is operatively coupled to the support member. The first image
sensor is positioned to view the drip chamber within the first field of view. The
second image sensor has a second field of view and is ively coupled to the
support member. The second image sensor is positioned to view the drip chamber
within the second field of view.
The at least one processor is operatively coupled to the first and second
image sensors. The at least one processor receives a first image data from the first
image sensor and a second image data from the second image sensor, and the at
least one sor estimates at least one parameter of the liquid within the drip
chamber using the first and second image data.
The at least one parameter may be one of a type of formation of the liquid,
the volume of the liquid, and the shape of the liquid. The at least one processor
WO 96722
may determine an existence of a free flow condition using at least one of the first
and second sets of image data.
The flow meter may further include a background n positioned within
the field of view of the first image sensor such that the drip chamber is between the
first image sensor and the background pattern.
The at least one processor of the flow meter may estimate the at least one
parameter using the first set of image data by analyzing a distortion of the
background pattern caused by the liquid within the first field of view as viewed by
the first image sensor. The background pattern may be an array of lines having at
least one angle relative to an opening of the drip chamber when viewed from the
first image sensor within the first field of view using the first set of image data.
The at least sor may determine a free flow condition exists when the
liquid causes the array of lines to change angles by distortion caused by the liquid
when in the free flow condition as viewed within the first field of view from the first
image sensor.
The at least one processor may compare at least one of the first and second
image data to a background image to estimate the at least one parameter.
The at least one processor may compare at least one of the first and second
image data to the background image by calculating at least one of a difference
between the at least one of the first and second image data to the background
image, an te difference between the at least one of the first and second
image data to the background image, and/or a squared absolute difference
between the at least one of the first and second image data to the background
image.
[0074]The flow meter may include a non-transitory processor-readable memory in
ive communication with the at least one processor such that the memory
stores an operative set of processor executable instructions configured for
execution by the at least one sor. The ive set of processor executable
instructions, when executed by the at least one processor, controls the operation of
the at least one processor.
|n certain embodiments of the present disclosure, a flow meter includes a
coupler, a support , a background pattern, and at least one processor. The
coupler is adapted to couple to a drip chamber. The support member is operatively
coupled to the coupler. The image sensor has a field of view and is operatively
coupled to the support member. The image sensor is positioned to view the drip
chamber within the field of view. The background n is positioned within the
field of the view of the image sensor. The background pattern is positioned such
that the drip chamber is between the background pattern and the image sensor.
The at least one processor is operatively coupled to the image sensor to receive
image data therefrom. The at least one processor is configured to estimate at least
one parameter of liquid within the drip chamber using tion of the background
pattern caused by the liquid as ted by the image data. The distortion is
viewable within the field of view of the image sensor by the image sensor. The at
least one ter is at least one of a type of formation of the liquid, a volume of
the liquid, and a shape of the liquid. The background pattern may be an array of
lines having at least one angle relative to an g of the drip chamber when
viewed from the image sensor using the image data.
The at least one processor may determine an existence of a free flow
condition using the distortion of the background pattern caused by the liquid as
indicated by the image data. The at least processor may determine that a free flow
ion exists when the liquid causes the array of lines to change angles by
distortion caused by the liquid when in the free flow condition as viewed within the
field of view of the image sensor.
[0077]The flow meter may further include a non-transitory processor-readable
memory in operative communication with the at least one processor. The non-
transitory processor-readable memory may store an operative set of processor
executable instructions configured for execution by the at least one processor such
that the operative set of processor able ctions, when executed by the at
least one processor, controls the ion of the at least one processor.
|n certain embodiments of the present disclosure, a flow meter includes a
coupler, a support member, an image sensor, and at least one processor. The
r is adapted to couple to a drip chamber. The support member is operatively
coupled to the coupler. The image sensor has a field of view and is operatively
coupled to the support member such that the image sensor is positioned to view
the drip chamber within the field of view. The at least one processor is operatively
coupled to the image sensor to receive image data therefrom such that the at least
one processor compares an image of the image data to a reference image to
te at least one parameter of liquid within the drip chamber. The reference
image may be a dynamic reference image. The at least one processor may update
the reference image by multiplying each pixel of the reference image by a first
constant and adding a corresponding pixel of the image multiplied by a second
constant.
The flow meter may include a non-transitory processor-readable memory in
operative communication with the at least one processor. The non-transitory
processor-readable memory may include an operative set of processor able
instructions configured for execution by the at least one processor such that the
operative set of processor executable instructions, when executed by the at least
one processor, controls the ion of the at least one processor.
In certain embodiments of the t disclosure, a method for ng an
image sensor implemented by an operative set of processor executable instructions
configured for execution by at least one processor includes: selecting a region of
interest; determining if a pixel is within the region of interest; activating a light of a
backlight if the pixel is within the region of interest; and exposing the pixel. The
activating act may activate a subset of lights ing the light of the backlight.
The light of the backlight may form a uniform ght. The image sensor may
include the region of interest and the pixel.
The operative set of sor executable instructions may be stored on a
ansitory sor-readable memory in operative communication with the at
least one processor such that the at least one processor can perform the method.
The at least one processor may be coupled to an image sensor such that the
at least one processor performs the method using the image sensor. The region of
st may be a region of an image sensor that images a drip chamber. The
region of st may correspond to a drip chamber.
The method may further include: ing a vertical sync signal from an
image sensor; and receiving a horizontal sync signal from the image sensor. The at
least one processor may receive the vertical and horizontal sync signals from the
image sensor. The at least one processor may activate the light of the backlight in
accordance with at least one of the vertical and horizontal sync signals. The light
may be a light-emitting diode.
|n certain embodiments of the present disclosure, a flow meter includes a
coupler, a support member, an image sensor, a backlight, and at least one
processor. The coupler is adapted to couple to a drip chamber. The support
member operatively couples to the coupler. The image sensor has a field of view
and is operatively coupled to the support member such that the image sensor is
positioned to view the drip chamber within the field of view. The backlight has at
least one light. The backlight is coupled to the support member such that the
backlight is adapted to illuminate the image sensor to expose the image sensor
wherein the field of view of the image sensor at least partially images at least a
portion of the drip chamber. The least one processor is operatively coupled to the
image sensor to receive image data therefrom.
The at least one sor is configured to: select a region of interest of the
image sensor; determine if a pixel of the image sensor is within the region of
interest; te the light of the backlight if the pixel of the image sensor is within
the region of st; and expose the pixel of the image sensor.
The flow meter may further include a non-transitory processor-readable
memory readable by the at least one processor. The non-transitory processor-
readable memory includes an operative set of processor executable instructions
stored thereon configured to cause the at least one processor, when executed, to:
select the region of interest of the image sensor; determine if the pixel of the image
sensor is within the region of interest; activate the light of the backlight if the pixel of
the image sensor is within the region of interest; and expose the pixel of the image
sensor. The at least one processor may be further ured to: receive a vertical
sync signal from the image sensor; and receive a horizontal sync signal from the
image sensor. The at least one processor may activate the light of the ght in
accordance with at least one of the vertical and horizontal sync signals.
The at least one processor may select the region of st and determine if
the pixel of the image sensor is within the region of interest in accordance with the
image data. The region of interest is a region of the image sensor that images the
drip chamber. The region of st may correspond to the drip chamber.
The at least one processor may activate a subset of lights including the light
of the backlight. The light of the backlight may form a uniform backlight.
[0089]|n certain embodiments of the t disclosure, a method includes:
capturing an image including an image of a drip chamber using an image sensor
having a field of view ing the drip chamber; subtracting the image from a
background image to thereby te a difference image; converting each pixel of
the difference image to a true value if an absolute value of a respective pixel is
beyond a predetermined threshold or to a false value if the absolute value of the
respective pixel is less than the predetermined threshold; summing each row of the
converted difference image to generate a plurality of summation values, wherein
each summation value of the plurality of summation values corresponds to a
tive row of the converted ence image; and examining the plurality of
summation values. The method may be implemented by an ive set of
processor executable instructions stored on a non-transitory processor-readable
memory in operative communication with at least one processor such that the at
least one processor performs the method.
[0090]The act of examining the plurality of summation values may include
determining if a free flow condition exists within the drip chamber.
The act of determining if the free flow condition exists may include
determining if the plurality of summation values includes a plurality of contiguous
summation values above another predetermined threshold.
[0092]The act of ing the plurality of summation values may include
ining if a drop has been formed within the drip chamber.
The act of determining if the drop has been formed within the drip r
may include determining if the plurality of summation values includes a plurality of
contiguous summation values within a predetermined range greater than a
minimum value and less than a maximum value.
The method may optionally include smoothing the plurality of summation
values prior to the examining act. The smoothing act may be in accordance with at
least one of a spline function, a cubic spline function, a B-spline function, a Bezier
spline function, a polynomial interpolation, a moving e, a data smoothing
function, and a cubic-spline-type function.
The at least one processor may optionally be coupled to the image ,
and the at least one processor may perform the method using the image .
The method may optionally include the act of converting each pixel of the
difference image to an absolute value of each pixel after the subtracting act and
prior to the ting act.
The method may optionally include the act of converting each pixel of the
difference image to a squared value of each pixel after the subtracting act and prior
to the converting act.
|n certain embodiments of the present disclosure, a flow meter includes a
coupler, a support member, a light, and at least one processor. The coupler is
adapted to couple to a drip chamber. The support member is operatively coupled
to the coupler. The image sensor has a field of view and is operatively coupled to
the support member such that the image sensor is positioned to view the drip
chamber within the field of view. The light is coupled to the support member and is
adapted to illuminate the image sensor to expose the image sensor such that the
field of view of the image sensor at least partially images at least a portion of the
drip chamber.
[0099]The at least one sor is operatively d to the image sensor to
receive image data rom, and the at least one processor is configured to:
capture an image including an image of a drip chamber using the image sensor
having a field of view including the drip chamber; subtract the image from a
background image to y generate a ence image; convert each pixel of
the difference image to a true value if an absolute value of a respective pixel is
beyond a predetermined threshold or to a false value if the te value of the
respective pixel is less than the predetermined threshold; sum each row of the
converted difference image to generate a plurality of summation values, wherein
each ion value of the plurality of summation values corresponds to a
respective row of the converted difference image; and examine the plurality of
summation values.
The flow meter may include a non-transitory processor-readable memory
readable by the at least one processor such that the non-transitory processor-
readable memory includes an operative set of processor executable instructions
stored thereon ured to cause the at least one processor, when executed, to:
capture the image including the image of a drip r using the image sensor
having a field of view including the drip chamber; ct the image from the
background image to thereby generate the ence image; convert each pixel of
the difference image to the true value if the absolute value of the respective pixel is
beyond the predetermined threshold or to the false value if the absolute value of
the respective pixel is less than the predetermined threshold; sum each row of the
ted difference image to generate the plurality of summation values, wherein
each summation value of the plurality of summation values corresponds to the
respective row of the converted ence image; and examine the plurality of
summation .
The at least one processor may be further configured to ine if a
free flow condition exists within the drip chamber when the processor examines the
plurality of summation values.
The at least one processor may be r configured to determine if the
plurality of summation values includes a plurality of contiguous summation values
above another predetermined threshold when the at least one processor
determines if the free flow condition exists.
[00103] The at least one processor may be r ured to determine if a
drop has been formed within the drip chamber when the at least one processor
examines the plurality of summation values.
The at least one processor may be further configured to determine that a
drop has been formed if the plurality of summation values includes a plurality of
contiguous summation values within a predetermined range greater than a
minimum value and less than a maximum value and a location of the contiguous
summation values corresponds to a predetermined range of locations in which a
drop can form.
The at least one processor may be further configured to smooth the
plurality of summation values prior to when the at least one processor examines the
plurality of summation values.
] The at least one processor may smooth in accordance with at least one
of a spline function, a cubic spline function, a B-spline function, a Bezier spline
function, a polynomial olation, a moving average, a data smoothing function,
and/or a cubic-spline-type function.
The flow meter may further include a non-transitory processor-readable
memory having an operative set of processor executable ctions stored
thereon. The non-transitory processor-readable memory is in operative
ication with at least one processor such that the operative set of processor
executable instructions controls the operation of the at least one processor.
The at least one processor may be further configured to convert each
pixel of the difference image to an te value of each pixel after the subtraction
act and prior to the conversion.
The at least one processor may be further configured to convert each
pixel of the difference image to a squared value of each pixel after the subtraction
act and prior to the conversion.
In certain embodiments of the present disclosure, a method includes:
capturing an image of a drip chamber using an image sensor; identifying a ity
of pixels of interest within the image; determining a subset of pixels within the
plurality of pixels of interest, wherein each pixel of the plurality of pixels is
determined to be within the subset of pixels when there is a path to a baseline
corresponding to the drip chamber; performing a rotation operation on the subset of
pixels; and estimating a volume of the drop within the drip chamber by counting a
number of pixels within the rotated subset of pixels.
] The baseline may be a predetermined set of pixels within the image
sensor. The plurality of pixels of interests may be identified by comparing the
image to a background image.
] The method may optionally include one or more of: initializing the
background image; updating the ound image using the image captured by
the image ; updating an array of variances using the image captured by the
image sensor; and/or ng an array of integers in according with the image
captured by the image sensor.
[00113] The background image may be updated in accordance with:
P = P _ abackground )+ abackground ‘Pinputj
oundj ,j backgroundj ,j (1 ’
The array of variances may be updated in accordance with:
Utemp _ (Pbackgroundfl,j_ ‘Pinputj ,j )
2 2 2
Ubackgroundfl ,j _ Ubackgroundfl ,j (1 _ 3background ) + 3backgroundUtemp_
Each integer of the array of integers may pond to a number of
updates of a pixel of the background image. In some specific embodiments, the
comparison of the image to the background image only compares pixels within the
image to pixels within the background image if a tive integer of the array of
integers indicates a respective pixel within the background image has been
updated at least a predetermined number of times.
] The method may optionally include one or more of: fying a drop in
the image and a predetermined band near an edge of the drop; and initializing the
background image by setting each pixel of the background image to the image
unless it is within the identified drop or the predetermined band near the edge of
the drop.
The method may r include setting a pixel of the background image
to a predetermined value if a corresponding pixel of the image is within the
identified drop or the predetermined band near the edge of the drop. The
corresponding pixel of the image has a location corresponding to the pixel of the
background image.
The method may further include determining a baseline corresponding to
an opening of the drip chamber.
[00119] The act of determining a subset of pixels within the plurality of pixels of
interest that corresponds to a drop may include ining each of the plurality of
pixels of interest is within the subset of pixels if the respective pixel of the plurality
of pixels has a contiguous path back to the baseline of the drop forming at an
opening of the drip chamber.
[00120] The method may optionally include one or more of: capturing a first
image using the image sensor; fying the drop within the first image and a
predetermined band near an edge of the drop; initializing the background image by
setting each pixel to the first image unless it is within the identified drop or the
ermined band near the edge of the drop; setting pixels within the region of
the drop or within the predetermined band to a predetermined value; initializing an
array of integers; and initializing an array of variances.
The method may also include one or more of updating the ound
image, the array of integers, and/or the array of variances using the image.
In certain embodiments of the present sure, a flow meter includes a
coupler, a support member, an image sensor, and at least one processor. The
r is adapted to couple to a drip chamber. The support member is operatively
coupled to the coupler. The image sensor has a field of view and is ively
coupled to the support member. The image sensor is oned to view the drip
chamber within the field of view.
[00123] The at least one processor is operatively d to the image sensor to
receive image data therefrom, and the at least one processor is configured to:
capture an image of a drip chamber using the image sensor; identify a plurality of
pixels of interest within the image; determine a subset of pixels within the plurality
of pixels of st, wherein each pixel of the plurality of pixels is determined to be
within the subset of pixels when there is a path to a ne corresponding to the
drip chamber; m a on operation on the subset of pixels; and te a
volume of the drop within the drip chamber by counting a number of pixels within
the rotated subset of pixels.
The flow meter may also e a ansitory processor-readable
memory having an operative set of processor executable instructions stored
thereon. The non-transitory processor-readable memory is in operative
communication with the at least one processor such that the operative set of
processor executable instructions controls the operation of the at least one
processor.
The flow meter may also include a non-transitory sor-readable
memory readable by the at least one processor such that the non-transitory
processor-readable memory includes an operative set of processor able
instructions stored thereon configured to cause the at least one processor, when
executed, to: capture an image of a drip chamber using the image sensor; identify a
plurality of pixels of interest within the image; determine a subset of pixels within
the plurality of pixels of interest, wherein each pixel of the plurality of pixels is
determined to be within the subset of pixels when there is a path to a baseline
ponding to the drip chamber; perform a rotation operation on the subset of
pixels; and estimate a volume of the drop within the drip chamber by counting a
number of pixels within the rotated subset of pixels.
The baseline may be a predetermined set of pixels within the image
sensor. The plurality of pixels of interests may be identified by comparing the
image to a background image. The at least one processor may be further
configured to initialize the background image and/or to update the background
image using the image captured by the image sensor.
The background image may be updated in accordance with:
P =P _ abackground )+ abackground ‘Pinputfl
backgroundfl ,j oundfl ,j (1 ’
The at least one processor may be further configured to update an array
of variances using the image captured by the image sensor.
The array of variances may be updated in accordance with:
Utemp _ (Pbackgroundfl,j_ ‘Pinputj ,j )
2 2 2
Ubackgroundfl ,j _ Ubackgroundfl ,j (1_ _ 3background ) + 3backgroundUtemp
The at least one sor may be further configured to update an array
of integers in according with the image captured by the image sensor. Each integer
of the array of integers corresponds to a number of updates of a pixel of the
ound image.
Optionally, in some embodiments, the comparison of the image to the
background image only compares pixels within the image to pixels within the
background image if a respective integer of the array of integers indicates a
tive pixel within the background image has been updated at least a
predetermined number of times.
[00132] The at least one sor may be further configured to: identify a drop in
the image and a predetermined band near an edge of the drop; and initialize the
background image by setting each pixel of the background image to the image
unless it is within the identified drop or the predetermined band near the edge of
the drop.
[00133] The at least one processor may be r configured to set a pixel of the
background image to a predetermined value if a corresponding pixel of the image is
within the identified drop or the predetermined band near the edge of the drop.
In certain ments of the present disclosure, the corresponding pixel
of the image has a location corresponding to a location of the pixel of the
background image.
The at least one processor may be further configured to determine a
baseline corresponding to an opening of the drip chamber.
The at least one processor may be further configured to determine
whether each of the plurality of pixels of interest is within the subset of pixels if the
tive pixel of the plurality of pixels has a contiguous path back to the baseline
of the drop forming at an opening of the drip r to determine if the subset of
pixels are within the ity of pixels of interest that corresponds to a drop.
The at least one processor may be further configured to: capture a first
image using the image sensor; identify the drop within the first image and a
predetermined band near an edge of the drop; initialize the background image by
setting each pixel to the first image unless it is within the identified drop or the
ermined band near the edge of the drop; set pixels within the region of the
drop or within the predetermined band to a predetermined value; initialize an array
of integers; and initialize an array of variances.
The at least one processor may be further configured to update the
background image, the array of integers, and/or the array of variances using the
image.
In certain embodiments of the present disclosure, a flow meter includes
an image sensor means and a flow rate estimator means. The image sensor
means is for capturing a plurality of images of a drip chamber. The flow rate
estimator means is for estimating the flow of fluid through the drip chamber using
the plurality of images.
] The flow rate estimator means may include a processor means for
estimating the flow of fluid through the drip chamber using the ity of .
The flow meter may further include a memory means in operative
communication with the processor means to provide an operative set of processor
executable instruction to cause the processor means to estimate the flow of fluid
through the drip chamber using the plurality of images.
[00142] In certain embodiments of the present sure, a flow meter includes a
memory means having an operative set of sor executable instructions
configured for being executed; and a processor means for executing the ive
set of processor executable instructions for implementing a flow rate estimator
means for estimating the flow of fluid through the drip r using the plurality of
images.
In certain embodiments of the present disclosure, a method includes: a
step for capturing a plurality of images of a drip r; and a step for estimating
the flow of fluid through the drip r using the plurality of images. The method
may be implemented by an operative set of sor executable instructions
stored on a ansitory memory and executed by at least one processor.
In certain embodiments of the present disclosure, an apparatus includes:
a coupler adapted to couple to a drip chamber; a support member operatively
coupled to the coupler; an image sensor having a field of view and is operatively
d to the support member, wherein the image sensor is positioned to view the
drip chamber within the field of view; a valve configured to couple to a fluid tube in
fluid communication with the drip chamber, wherein the valve is configured to
regulate flow through the fluid tube to thereby regulate the fluid flow through the
drip chamber; and at least one sor operatively coupled to the image sensor
to receive image data therefrom, wherein the at least one processor is configured
to: capture a plurality of images of the drip chamber using the image sensor;
estimate a volume growth rate of the drop within the drip chamber using the
plurality of images; receive a set point corresponding to a fluid flow rate through the
fluid tube; adjust a control system in accordance with the estimated volume growth
rate of the drop to achieve the set point; and output a control signal from the control
system to an actuator of the valve to control actuation of the valve in accordance
with the adjusted control system.
The apparatus may include a non-transitory processor-readable memory
having an operative set of sor executable instructions stored thereon. The
non-transitory processor-readable memory may be in operative communication with
at least one sor such that the operative set of processor executable
instructions controls the operation of the at least one processor.
The apparatus may include a non-transitory processor-readable memory
readable by the at least one processor. The non-transitory processor-readable
memory may include an operative set of processor executable ctions stored
thereon configured to cause the at least one processor, when executed, to: capture
the plurality of images of the drip chamber using the image ; te the
volume growth rate of the drop within the drip r using the plurality of
images; receive the set point ponding to a fluid flow rate h the fluid
tube; adjust the control system in accordance with the estimated volume growth
rate of the drop to achieve the set point; and output the l signal from the
control system to an actuator of the valve to control actuation of the valve in
accordance with the adjusted control system.
The control system may be at least one of a proportional—integral—
derivative control system, a tional—integral control system, tional-
derivative control system, a proportional l system, an integral control system,
a neural net control system, a fuzzy logic control system, and/or a bang-bang
l system.
The control system may correlate the estimated volume growth rate of
the drop with the fluid flow through the fluid tube.
The valve may include: a curved, elongated support member elastically
deformable and having first and second ends; and an opposing support member
configured to position the fluid tube against the curved, elongated support member
between the first and second ends, wherein deformation of the , elongated
support member by movement of the first and second ends toward each other
reduces an internal volume of the fluid tube. The actuator may be configured to
move the first and second ends toward each other.
The valve may include: a first elongated support member defining a
length; and a second elongated support member defining a length, wherein the
length of the second elongated support member is disposed in spaced relation with
the length of the first elongated support member to cooperate with the first
elongated support member to compress the fluid tube. The actuator may be in
mechanical engagement with at least one of the first and second ted support
members to actuate the first and second elongated support s toward each
other to thereby compress the fluid tube disposed therebetween to regulate flow of
fluid within the fluid tube; Actuation of the actuator actuates the first and second
elongated t members to regulate fluid flow within the tube in accordance with
an approximate sigmoid curve.
[00151] The valve may include: a first elongated support member ng a
length; and a second elongated support member defining a length, wherein the
length of the second elongated support member is disposed in spaced relation with
the length of the first elongated support member to cooperate with the first
ted support member to compress the fluid tube. The actuator is in
mechanical engagement with at least one of the first and second elongated support
members to actuate the first and second elongated support members toward each
other to y compress the fluid tube disposed therebetween to regulate flow of
fluid within the tube; ion of the or actuates the first and second
elongated support members to regulate fluid flow within the fluid tube in accordance
with an approximate Gompertz curve.
] The valve may include: a first elongated support member defining a
length; and a second elongated support member defining a length, wherein the
length of the second elongated t member is disposed in spaced relation with
the length of the first elongated support member to cooperate with the first
elongated support member to compress the fluid tube. The actuator is in
mechanical engagement with at least one of the first and second ted support
members to actuate the first and second elongated support members toward each
other to thereby compress the fluid tube disposed therebetween to regulate flow of
fluid within the fluid tube; Actuation of the actuator actuates the first and second
elongated support s to regulate fluid flow within the tube in accordance with
an approximate generalized logistic function.
The valve may include: a first support member that forms at least one of
an arc, a plurality of arcs, a curve, a plurality of , an arcuate shape, a plurality
of arcuate shapes, an S—shape, a C-shape, a convex shape, a plurality of convex
shapes, a concave shape, and a plurality of convex shapes; and a second support
member disposed in spaced relation with the first support member to cooperate
with the first support member to compress the fluid tube along a length of the fluid
tube at least substantially r than the diameter of the fluid tube. The actuator
in is mechanical engagement with at least one of the first and second support
members to actuate the first and second support members toward each other to
thereby compress the fluid tube disposed therebetween to regulate flow of fluid
within the fluid tube; Actuation of the actuator actuates the first and second support
members to te fluid flow within the fluid tube in accordance with an
approximate nonlinear function.
The valve may e: a , elongated support member elastically
deformable and having first and second ends; and an opposing support member
configured to define a conduit with the curved, elongated support member. The
conduit is defined between the curved, elongated support member and the
opposing . The fluid tube is disposed within the t and deformation of
the curved, elongated support member by movement of the first and second ends
toward each other reduces an internal volume of the fluid tube within the t.
The valve may be an inverse-Bourdon-tube valve coupled to the fluid
tube to regulate the fluid flowing through the fluid path of the fluid tube.
] The valve may include: a first flexible member; and a second flexible
member operatively coupled to the first flexible member. The fluid tube may be
disposed between the first and second le members. The first and second
flexible members are configured to flex to thereby regulate flow of fluid passing
through the fluid tube, and the or is coupled to at least a first end of the first
flexible member and a second end of the first flexible member.
The valve may include a first C-shaped member defining inner and outer
surfaces; and a second C-shaped member defining inner and outer surfaces. At
least one of the outer surface of the first C-shaped member and the inner e of
the second C-shaped member is configured to receive the fluid tube. The inner
surface of the second ed member is disposed in spaced relation to the outer
surface of the first C-shaped member. The actuator is coupled to the first and
second C-shaped members to bend the first and second C-shaped members to
compress the fluid tube.
The valve may include: a first flexible sheet; and a second flexible sheet
operatively coupled to the first flexible sheet. The first and second flexible sheets
are configured to receive the fluid tube therebetween. The first and second flexible
sheets are configured to flex to thereby regulate flow of fluid passing through the
fluid tube. The actuator is coupled to the first and second flexible sheets to
regulate flow of fluid passing through the fluid tube.
The valve may include: a first curve-shaped member defining inner and
outer surfaces; and a second curve-shaped member defining inner and outer
surfaces. The inner surface of the second curve-shaped member is disposed in
spaced relation to the outer surface of the first curve-shaped member with the fluid
tube disposed between the first and second curved-shaped members, and the
actuator is d to the first and second shaped members to bend the first
and second shaped s to thereby regulate the flow of fluid within the
fluid tube.
The valve may include: a first curve-shaped member defining inner and
outer surfaces, the first curve-shaped member having first and second receiving
members at opposite ends of the first curve-shaped member; and a second curve-
shaped member defining inner and outer surfaces, the second curve-shaped
member having first and second fasteners at opposite ends of the second curve-
shaped member. The first ing member of the first curve-shaped member is
configured to engage the first fastener of the second curve-shaped member. The
second receiving member of the first curve-shaped member is configured to
engage the second er of the second curve-shaped member. The actuator is
coupled to the first and second curve-shaped members to bend the first and
second curve-shaped members to regulate the flow of fluid within the fluid tube
disposed therebetween.
The valve may e: a first curved, elongated support member
elastically deformable and having first and second ends; and a second curved,
elongated support member cally able and having first and second
ends, wherein the second , elongated support member is configured to
position the fluid tube against the first curved, elongated support, wherein
deformation of the first and second curved, elongated support members by
movement of the first and second ends of the first curved, elongated support
member toward each other reduces an internal volume of the fluid tube; a first
connector coupled to the first end of the first curved, elongated t member
and coupled to the first end of the second curved, elongated support member; a
second connector coupled to the second end of the first curved, elongated support
member and coupled to the second end of the second curved, elongated support
, wherein the second connector defines a hole; a connecting member
having an end coupled to the first connector and another end configured for
ion into the hole of the second tor, wherein the connecting member
defines a threaded rod at least along a portion thereof; and a knob having a t
configured to t onto the connector member when moved from the another
end of the connecting member toward the end of the connector member, wherein
the knob is further configured to engage the threaded rod of the connecting
member; The or may be coupled to the knob to rotate the knob.
The valve may include: a base defining a hole configured to receive the
fluid tube; a plurality of fingers each having an end d to a base; and a ring
ured to slide from the base and along the plurality of fingers. Movement of the
ring from the base compresses the fingers against the fluid tube. The ring is
configured to onally lock against the ity of fingers. The actuator is coupled
to the ring to slide the ring.
The valve may include: a conically-shaped member having a surface for
wrapping the fluid tube therearound; and a complementing member configured to
engage the conically-shaped member for compressing the tube. The actuator is
configured to compress the conically-shaped member against the complementing
member to thereby compress the fluid tube.
The control system may be implemented in hardware, software, a
ation of hardware and software, and/or by at least one operational amplifier.
[00165] The apparatus may include a non-transitory processor-readable memory,
wherein: the control system is implemented by an operative set of processor
executable instructions configured for execution by the at least one processor, the
operative set of sor executable instructions is stored on the ansitory
processor-readable memory, and the non-transitory processor-readable memory is
in operative communication with the at least one processor to operatively
communicate the operative set of sor able instructions to the at least
one processor for execution by the at least one processor.
The set point may be compared to the volume growth rate of the drop to
adjust the control . The set point may be compared to the volume growth
rate of the drop to determine an error signal. The error signal may be the difference
between the set point and the volume growth rate of the drop. The error signal may
be passed through a signal processing apparatus to generate the output signal.
The signal processing apparatus may implements a proportional-integral-derivative
controller with at least one non-zero gain parameter.
In another embodiment of the present disclosure, an apparatus for
regulating fluid flow includes a , elongated support member and an opposing
support member. The curved, elongated support member is elastically able
and has first and second ends. The first end is configured to pivotally couple to first
and second dog bone linkers, and the second end is configured to pivotally couple
to third and fourth dog bone linkers. The ng support member is configured to
position a tube against the curved, elongated support member between the first
and second ends such that deformation of the curved, elongated support member
by movement of the first and second ends toward each other s an internal
cross-section along a length of the tube. The first end of the opposing support
member is configured to pivotally couple to the first and second dog bone linkers,
and a second end of the opposing support member is configured to pivotally couple
to the third and fourth dog bone linkers.
] The first end of the curved, ted support member may include an
engagement finger configured to engage a rack. The second end of the curved
elongated may be configured to pivotally couple to the rack. The apparatus may
include a knob coupled to the first end of the curved, elongated t member to
move the rack.
] In yet another embodiment of the present disclosure, a flow meter
includes a r, a support member, an image sensor, a laser, and at least one
processor. The coupler is adapted to couple to a drip chamber. The support
member is operatively coupled to the coupler. The image sensor has a field of view
and is operatively coupled to the support member, and the first image sensor is
configured to view the drip chamber within the field of view. The laser is configured
to shine the optical light onto the binary optics assembly.
The at least one processor is operatively coupled to the image sensor
such that: (1) the at least one processor receives data from the image sensor
having at least a portion of the back pattern represented therein; and (2) the at
least one processor estimates at least one parameter of liquid within the drip
chamber using the image data.
In yet another embodiment of the present disclosure, a flow meter
includes a coupler, a support member, first and second electrodes, and at least one
processor. The coupler is adapted to couple to a drip chamber. The support
member is operatively coupled to the coupler. The first ode is ured to
couple to a fluid line in fluid communication with the drip chamber. The second
electrode is configured to couple to the fluid line in fluid communication with the drip
chamber.
[00172] The at least one sor is operatively coupled to the first and second
electrodes to measure a capacitance etween, and the at least one processor
is configured to monitor the capacitance. The at least one processor may be
configured to determine if a streaming condition exists within the drip chamber
using the monitored capacitance.
[00173] In yet r embodiment of the present disclosure, a safety valve
includes a g, first and second occluding arms, first and second axles, and a
spring. The housing is configured to hold a tube. The first and second occluding
arms are lly coupled together. The first axle is lly coupled to a distal
end of the first occluding arm. The second axle is pivotally d to a distal end
of the second occluding arm. The spring is disposed adjacent to the first and
second occluding arms on an opposite side to the tube configured to spring load
the first and second occluding arm. The safety valve is configured to discharge the
spring and occlude the tube when the first and second occluding arms pivot away
from the spring along their common pivot by a predetermined amount. A id
may be used to engage the first and second occluding arm to discharge the spring.
In yet another embodiment of the t disclosure, an apparatus
includes a r, a support member, and at least one processor. The coupler is
adapted to couple to a drip chamber. The support member is operatively coupled to
the coupler. The image sensor has a field of view and is operatively coupled to the
support member. The image sensor is configured to view the drip r within
the field of view. The at least one processor is operatively coupled to the image
sensor to receive image data therefrom, and the at least one processor is
configured to: (1) capture an image of the drip chamber; (2) position a template
within the captured image to a first position; (3) average the pixels within the
template to determine a first average; (4) move the template to a second position;
(5) average the pixels within the template to determine a second average; (6)
determine that the template is located at an edge of a drop if a difference between
the second average and the first average is greater than a predetermined threshold
value; (7) and correlate the second on with a volume of the drop.
In yet another ment of the present disclosure, a method
implemented by at least one processor executing an operative set of processor
executable instructions configured for being executed by the at least one processor
for estimating a flow rate is disclosed. The method includes: (1) capturing an image
of the drip chamber; (2) positioning a te within the captured image to a first
position; (3) averaging the pixels within the template to determine a first average;
(4) moving the template to a second position; (5) averaging the pixels within the
template to determine a second average; (6) determining that the te is
located at an edge of a drop if a difference between the second average and the
first average is greater than a predetermined threshold value; and (7) correlating
the second position with a volume of the drop.
In yet r embodiment of the present disclosure, a flow meter
includes a coupler, a support member, a modulatable backlight assembly, an image
sensor, and at least one processor. The coupler is adapted to couple to a drip
chamber. The support member is operatively coupled to the coupler. The
modulatable backlight assembly is ured to provide a first backlight and a
second backlight. The image sensor has a field of view and is operatively coupled
to the support member. The image sensor is configured to view the drip chamber
within the field of view and the modulatable backlight assembly. The at least one
processor is operatively coupled to the image sensor and the modulatable backlight
assembly such that the at least one processor receives data from the image sensor
having at least a n of the modulatable backlight assembly ented
therein, and the at least one processor is configured to modulate the backlight
ly to the first backlight when ting a drop size and to modulate the
backlight assembly to the second backlight. The first backlight may be a diffuser
backlight having no pattern and the second backlight may be a diffuser backlight
having a striped pattern.
] In yet another embodiment of the present disclosure, a tube er
includes first and second gears. The second gear is ed abutted against
the first gear. The first and second gears define a space along radial ns of
the first and second gears to allow a tube to flex therebetween. The first and
second gears are further configured to restore the tube when rotated such that the
space is not oned between the first and second gears.
[00178] In yet another embodiment of the present disclosure, a valve includes
first and second metallic strips, and first and second guiding members. The first
guiding member is coupled to distal ends of the first and second metallic strips.
The second guiding member is coupled to proximal ends of the first and second
metallic strips. The first and second metallic strips are configured to compress a
tube when the distal ends of the first and second metallic strips are actuated
towards the proximal ends of the first and second metallic strips. The valve may
further include a string (e.g., a metal string or a string made of any other material)
threaded through the first and second metallic strips to spiral around the tube.
In yet another embodiment of the present sure, a valve includes
first and second clamshell configured to provide a cavity between the first and
second clamshells. The first and second clamshells are configure to receive a tube
therebetween and within the cavity. The valve also includes a bladder ed
within the cavity and a pump configured to inflate or deflate the bladder to regulate
flow of fluid within the tube.
[00180] In yet another embodiment of the present disclosure, an apparatus
includes a coupler, a t member, an image , and at least one
processor. The coupler is adapted to couple to a drip r. The support
member is operatively coupled to the coupler. The image sensor has a field of view
and is operatively coupled to the support member. The image sensor is configured
to view the drip chamber within the field of view.
The at least one processor is operatively coupled to the image sensor to
receive image data therefrom and is configured to: (1) capture a first image; (2)
create a first thresholded image from the first image by comparing each pixel of the
first image to hold value; (3) determine a set of pixels within the first
olded image ted to a predetermined set of pixels within the first
thresholded image; (4) filter all remaining pixels of the first thresholded image that
are not with the set of pixels, the filter operates on a pixel-by-pixel basis within the
time domain to te a first filtered image; (5) remove pixels determined to not
be part of a drop from the first thresholded image using the first filtered image to
te a second image; (6) determine a second set of pixels within the
second image connected to a predetermined set of pixels within the second image
to generate a third image, the third image identifies the second set of pixels within
the second image; (7) determine a first length of the drop by ng the number
of rows containing pixels corresponding to the second set of pixels within the third
image, the first length corresponding to a first estimated drop size; (8) update a
background image using the first image; (9) create a second thresholded image by
comparing first image with background image; (10) sum the rows of second
thresholded to create a plurality of row sums, each row sum corresponds to a row
of the second thresholded image; (11) start at a row position of the second
thresholded image having a first sum of the plurality of sums that corresponds to
the first length; (12) increment the row position until the row position corresponds to
a corresponding row sum that is zero; (13) determine a second length is equal to
the present row position, the second length corresponding to a second estimated
drop size; and (14) average the first and second lengths to determine a average
length, the average length ponding to a third estimated drop size.
In yet another embodiment of the present disclosure, a method
implemented by at least one processor ing an operative set of processor
executable instructions ured for being executed by the at least one processor
for estimating a flow rate includes: (1) capturing a first image; (2) creating a first
thresholded image from the first image by comparing each pixel of the first image to
a threshold value; (3) determining a set of pixels within the first thresholded image
connected to a predetermined set of pixels within the first thresholded image; (4)
filtering all ing pixels of the first thresholded image that are not with the set of
pixels, the filter operates on a pixel-by-pixel basis within the time domain to
generate a first filtered image; (5) removing pixels determined to not be part of a
drop from the first thresholded image using the first filtered image to generate a
second image; (6) determining a second set of pixels within the second image
connected to a predetermined set of pixels within the second image to generate a
third image, the third image identifies the second set of pixels within the second
image; (7) determining a first length of the drop by counting the number of rows
containing pixels ponding to the second set of pixels within the third image,
the first length corresponding to a first estimated drop size; (8) updating a
background image using the first image; (9) ng a second thresholded image
by comparing first image with background image; (10) summing the rows of second
thresholded to create a plurality of row sums, each row sum corresponds to a row
of the second thresholded image; (11) starting at a row position of the second
thresholded image having a first sum of the plurality of sums that ponds to
the first length; (12) incrementing the row on until the row position
corresponds to a ponding row sum that is zero; (13) determining a second
length is equal to the t row position, the second length ponding to a
second estimated drop size; and (14) averaging the first and second lengths to
determine a average length, the average length corresponding to a third ted
drop size.
In yet another embodiment of the present disclosure, a flow meter
includes a coupler, a support member, first and second loop antennas, and at least
one processor. The coupler is adapted to couple to a drip chamber. The support
member is operatively coupled to the coupler. The first loop antenna is disposed
adjacent to a fluid line in fluid communication with the drip chamber. The second
loop antenna is disposed adjacent to the fluid line. The at least one processor is
ively coupled to the first and second loop antennas to measure a magnetic
coupling therebetween. The at least one processor is ured to monitor the
magnetic coupling therebetween to determine if a streaming condition exists within
the drip chamber.
In yet another ment of the present disclosure, a method
implemented by an operative set of processor executable instructions includes: (1)
determining a plurality of points of interest in an image; (2) randomly selecting N-
points of interest of the ity of points of interest; and/or (3) identifying a single,
unique, geometric feature characterized by N-parameters corresponding to t
of interest.
In yet another embodiment of the present disclosure, a system includes a
non-transitory memory and one or more processors. The non-transitory memory
has stored thereon a plurality of instructions. The one or more processors are in
operative communication with the non-transitory memory to execute the plurality of
instruction. The plurality of instructions is configured to cause the processor to: (1)
determine a plurality of points of interest in an image; (2) randomly select N-points
of interest of the plurality of points of interest; and/or (3) identify a single, unique,
geometric feature characterized by N-parameters ponding to N-point of
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects will become more apparent from the following
detailed description of the s embodiments of the present sure with
reference to the drawings wherein:
Fig. 1 shows a block m of a system for regulating fluid flow in
ance with an embodiment of the present disclosure;
Fig. 2 shows a flowchart diagram of a method for ng an image
sensor in accordance with an embodiment of the t disclosure;
Fig. 3 shows a timing diagram rating an embodiment of the method
of Fig. 2 in accordance with an embodiment of the present disclosure;
Figs. 4A-4B show illustrations of image data (i.e., images) captured by a
flow meter of a drip chamber to illustrate an embodiment of the method for
exposing an image sensor of Fig. 2 in accordance with the timing m of Fig. 3
in accordance with an embodiment of the present disclosure;
Fig. 5 shows a diagram of a flow meter and valve that are integrated
together for coupling to a drip chamber and an IV bag in accordance with an
embodiment of the present disclosure;
[00192] Fig. 6 is a block diagram of an imaging system of a flow meter for
imaging a drip chamber in accordance with an embodiment of the present
disclosure;
Fig. 7 is a graphic illustration of an image captured by the image sensor
of the system of Fig. 6 in ance with an embodiment of the present disclosure;
[00194] Fig. 8 is a block diagram of an imaging system of a flow meter for
imaging a drip chamber utilizing a background pattern in accordance with an
embodiment of the present disclosure;
WO 96722 2012/071142
] Fig. 9 is a graphic illustration of an image captured by an image sensor of
a flow meter disclosed herein when a free flow condition exists in accordance with
an embodiment of the present disclosure;
Fig. 10 is a graphic illustration of an image ed by an image sensor
of a flow meter for use as a background image in accordance with an ment
of the present sure;
Fig. 11 is a graphic illustration of an image captured by an image sensor
when drops are being formed within a drip chamber in accordance with an
embodiment of the t disclosure;
[00198] Fig. 12 is a graphic illustration of an image captured by an image sensor
for use as a background image in accordance with an embodiment of the present
disclosure;
Fig. 13 is a graphic illustration of a difference between the images of
Figs. 11 and 12 with onal processing in accordance with an embodiment of
the present disclosure;
] Fig. 14 is a graphic representation of some of the image processing
med using Figs. 11-13 to determine if a free flow condition exists in
accordance with an embodiment of the present disclosure;
Fig. 15 is a graphic illustration of an image captured by the image sensor
when a free flow condition exists in accordance with an embodiment of the present
disclosure;
Fig. 16 is a graphic illustration of an image ed by the image sensor
for use as a background image in accordance with an embodiment of the present
disclosure;
[00203] Fig. 17 is a graphic illustration of a difference between the images of
Figs. 15 and 16 with some additional processing for use in detecting a free flow
condition in accordance with an embodiment of the present disclosure;
Fig. 18 is a graphic representation of some of the image processing
performed using Figs. 15-17 to determine if a free flow condition exists in
accordance with an embodiment of the present disclosure;
Fig. 19 illustrates a template for pattern matching to determine if a free
flow condition exits in accordance with an ment of the present disclosure;
Fig. 20 is a graphic illustration of a difference between a reference image
and an image containing a stream processed with edge detection and line detection
2012/071142
for use in detecting a free flow condition in accordance with an embodiment of the
present disclosure;
Fig. 21 is a graphic illustration of an image of a drip chamber captured by
an image sensor when a free flow condition exists in accordance with an
embodiment of the present disclosure;
Fig. 22 is a block diagram of an imaging system for use with a flow meter
having a background pattern with stripes and a light source g on the stripes
from an adjacent location to an image sensor in accordance with an embodiment of
the present disclosure;
[00209] Fig. 23 is a block diagram of an imaging system for use with a flow meter
having a background n with stripes and a light source shining on the stripes
from behind the background pattern relative to an opposite end of an image sensor
in accordance with an embodiment of the present disclosure;
Fig. 24 illustrates an image from an image sensor when a drop distorts
the background pattern of Fig. 23 in accordance with an embodiment of the present
disclosure;
Fig. 25 is a block diagram of an imaging system for use with a flow meter
having a background pattern with a checkerboard pattern and a light source shining
on the stripes from behind the background pattern relative to an opposite end of an
image sensor in accordance with an embodiment of the present sure;
Fig. 26 shows an image from the image sensor of Fig. 25 when a drop
distorts the background n in accordance with an ment of the present
disclosure;
Figs. 27-28 show a flow chart illustration of a method for estimating a
volume of a drop within a drip chamber in accordance with an embodiment of the
present disclosure;
Figs. 29-31 illustrate images used or generated by a flow meter to
estimate a volume of a drop within a drip chamber using the method illustrated by
Figs. 27-28 in ance with an ment of the t disclosure;
[00215] Fig. 32 shows pseudo code for identifying a plurality of pixels of interest
in ance with the method of Figs. 27-28 in accordance with an embodiment of
the present disclosure;
] Figs. 33-36 illustrate additional images used or generated by a flow meter
to estimate a volume of a drop within a drip chamber using the method rated
by Figs. 27-28 in accordance with an embodiment of the present disclosure;
Fig. 37 shows pseudo code for determining a subset of pixels within the
plurality of pixels of interest that ponds to a drop in accordance with an
embodiment of the present disclosure;
Fig. 38 shows a ray diagram illustrating the diameter of a blur circle to
illustrate aspects of an image sensor of an imaging system sed herein in
accordance with an embodiment of the present disclosure;
[00219] Fig. 39 is a graphic illustrating a calculated blur circle for a variety of lens-
to-focal plane separations and lens-to-image separations for an image sensor of an
imaging system disclosed herein in accordance with an embodiment of the present
disclosure;
Fig. 40 is a graphic illustrating a blur circle divided by a pixel size when a
20 millimeter focal length lens of an image sensor of an imaging system disclosed
herein is used in accordance with an embodiment of the present sure;
Fig. 41 is a graphic illustrating a blur circle divided by a pixel size when
a 40 millimeter focal length lens of an image sensor of an imaging system sed
herein is used in accordance with an embodiment of the present disclosure;
[00222] Fig. 42 shows a table illustrating the corresponding fields of view about
the optical axis for the s of two configurations of an imaging system disclosed
herein in ance with an embodiment of the present disclosure;
Fig. 43 shows a flow meter coupled to a drip chamber in ance with
an embodiment of the present disclosure;
[00224] Fig. 44 shows the flow meter and drip r of Fig. 43 with the door
open in accordance with an embodiment of the present disclosure;
Fig. 45 shows a flow meter coupled to a drip chamber in accordance with
an embodiment of the present disclosure;
Fig. 46 shows a flow meter and a pinch valve coupled to the body of the
flow meter to control the flow of fluid into a patient in accordance with an
embodiment of the present sure;
Fig. 47 shows a close-up view of the pinch valve that is coupled to the
body of the flow meter of Fig. 46 in accordance with an embodiment of the present
disclosure;
2012/071142
Fig. 48 shows a flow meter and a pinch valve wherein the flow meter
includes two image sensors in accordance with another embodiment of the present
disclosure;
Fig. 49 shows a flow meter and a valve including two curved, elongated
support members to control the flow of fluid into a patient in accordance with an
embodiment of the present disclosure;
Figs. 50A-SOB show up views of the valve of Fig. 49 in accordance
with an embodiment of the present disclosure;
] Figs. D show several views of a flow meter with a monitoring
client, a valve, a drip chamber, an IV bag and a fluid tube wherein the flow meter
includes a receiving portion to receive the valve in accordance with an embodiment
of the present disclosure;
Figs. D show several views of another flow meter with a valve, a
drip chamber, and a tube wherein the flow meter has a receiving portion to receive
the valve in accordance with an embodiment of the present disclosure;
Fig. 53A shows another view of the valve of Figs. 51A-51 D and D
in accordance with an embodiment of the present disclosure;
Figs. 538-53C show two exploded views of the valve of Fig. 53A in
accordance with an embodiment of the t sure;
[00235] Fig. 54 shows the valve of Fig. 53 in manual use in accordance with an
embodiment of the present disclosure;
Fig. 55 shows a valve that es two flexible s in accordance
with an embodiment of the present disclosure;
Figs. 56A-56C show several views of a valve having two curved,
elongated support members with one of the elongated support members having a
plurality of ridges adapted to engage a tube in ance with an embodiment of
the present disclosure;
Figs. 57A-57C show several views of a valve having a ratchet that
engages a connecting member in accordance with an embodiment of the present
disclosure;
Figs. 57D-57E show two exploded views of the valve of Figs. 57A-57C in
accordance with an embodiment of the present disclosure;
Figs. 58A-58D show several views of a valve having two elongated
support members, a connecting member, and a screw-type actuator in ance
with another embodiment of the present disclosure;
Figs. 59A-59C show several views of a body of a valve in accordance
with an embodiment of the present disclosure;
Figs. 59D-59G show several views of a knob for use with the body shown
in Figs. 59A-59C in accordance with an embodiment of the present disclosure;
] Fig. 59H shows the assembled valve that includes the body shown in
Figs. 59A-59C coupled to the knob of Figs. 59D-59G in accordance with an
embodiment of the t disclosure;
Fig. 60 shows a valve having a guiding protrusion in accordance with an
ment of the present disclosure;
Fig. 61 shows a motor and a valve-securing structure for coupling to the
valve of Fig. 60 in accordance with an embodiment of the present disclosure;
] Fig. 62 shows the valve of Fig. 60 secured to the motor and the valve-
securing structure of Fig. 61 in accordance with an embodiment of the present
disclosure;
Fig. 63 shows another motor and valve-securing structure for coupling to
the valve of Fig. 60 in accordance with an embodiment of the present sure;
[00248] Fig. 64A shows a valve having a collar and several fingers for regulating
fluid flow through a fluid line in accordance with an embodiment of the t
disclosure;
Fig. 648 shows a cross-sectional view of the valve of Fig. 64A in
accordance with an embodiment of the present disclosure;
[00250] Fig. 65 shows a cross-sectional view of a valve having two curved
es for positioning a fluid tube therebetween to regulate fluid flow through the
fluid tube in accordance with an embodiment of the t disclosure;
Figs. 66A-66G show several views of a valve having a knob to move a
connecting member which is locked into position after movement of the knob in
ance with an ment of the t disclosure;
Fig. 67 shows a graphic that illustrates actuation vs. flow rates for a valve
in accordance with an embodiment of the present disclosure;
Fig. 68A shows a flow meter that uses binary optics in accordance with
an embodiment of the present disclosure;
Figs. F show several views of a safety valve that may be used
with a flow meter in accordance with an embodiment of the present disclosure;
Fig. 70 shows a flow chart diagram illustrating a method of estimating
drop growth and/or flow within a drip chamber in accordance with an embodiment
of the present disclosure;
Figs. 71A-71 B show images take by a flow meter with a template overlaid
therein to illustrate the method of Fig. 70 in accordance with an embodiment of the
present disclosure;
Fig. 72 shows a modulateable backlight assembly in ance with an
ment of the present disclosure;
Figs. 73A-73C show several views of a tube-restoring apparatus in
ance with an embodiment of the present disclosure;
Fig. 74 shows a system for regulating fluid flow using a valve having two
flexible strips in accordance with an embodiment of the present disclosure;
[00260] Fig. 75 shows the valve of Fig. 74 in accordance with an embodiment of
the present disclosure;
] Fig. 76A shows a valve that utilizes a fluid-based bladder in accordance
with an embodiment of the present disclosure;
Fig. 76B shows a cross-sectional view of the led valve of Fig. 76A
with two elastomeric fillers in accordance with an embodiment of the present
disclosure;
Fig. 77 shows a system for regulating fluid flow using a valve having two
flexible strips actuateable by a linear actuator in accordance with an embodiment of
the present disclosure;
[00264] Fig. 78 shows the system of Fig. 77 with the valve actuated in
accordance with an embodiment of the t disclosure;
Fig. 79 shows a close-up of the valve of Figs. 77-78 in accordance with
an embodiment of the t disclosure;
Fig. 80 shows a close-up of the valve as actuated in Fig. 78 in
accordance with an embodiment of the t disclosure;
Fig. 81 shows several images for use to illustrate a method of ting
drop growth and/or fluid flow illustrated in Figs. 82A-82B in accordance with an
embodiment of the present disclosure; and
Figs. 82A-82B show a flow chart diagram illustrating a method of
estimating drop growth and/or fluid flow in accordance with an embodiment of the
t disclosure; and
Fig. 83 shows a flow chart m of a method for reducing noise from
condensation in accordance with an ment of the present disclosure.
DETAILED DESCRIPTION
Fig. 1 shows a block diagram of a system 1 for ting fluid flow in
ance with an embodiment of the present disclosure. For example, system 1
may regulate, monitor, and/or control the flow of fluid into a patient 3. The system 1
includes a fluid reservoir 2 for infusing fluid contained therein into the patient 3.
The fluid reservoir 2 is gravity fed into a drip chamber 4 via a fluid tube 5. The fluid
reservoir 2, the drip chamber 4, and the patient 3 may be considered as part of the
system 1, may be considered as separate or optional work pieces for the system 1
(e.g., any fluid reservoir 2 and drip chamber 4 may be used to treat any patient 3).
A flow meter 7 rs the drip chamber 4 to te a flow rate of
liquid flowing through the drip chamber 4. The fluid from the drip chamber 4 is
gravity-fed into a valve 6. The valve 6 regulates (i.e., varies) the flow of fluid from
the fluid reservoir 2 to the t 3 by regulating fluid flow from the drip chamber 4
to the patient 3. The valve 6 may be any valve as described herein, including a
valve having two curved-shaped members, a valve having two flexible sheets, a
valve that pinches (or uniformly compresses) on the tube over a significant length of
the tube, or the like. The valve 6 may be an inverse-Bourdon-tube valve that works
in an opposite way of a Bourdon tube in that a deformation of the fluid path causes
changes in fluid flow rather than fluid flow causing deformation of the fluid path.
In alternative embodiments, the system 1 optionally includes an infusion
pump 414 (e.g., a peristaltic pump, a finger pump, a linear peristaltic pump, a rotary
peristaltic pump, a cassette-based pump, membrane pump, other pump, etc.)
d to the fluid tube 5. The outlined box designated as 414 represents the
al nature of the infusion pump 414, e.g., the infusion pump may not be used
in some embodiments. The infusion pump 414 may use the flow meter 7 as
feedback to control the flow of fluid through the fluid tube 5. The infusion pump 414
may be in wireless communication with the flow meter 7 to receive the flow rate
therefrom. The infusion pump 414 may use a feedback control algorithm (e.g., the
WO 96722
control component 14 of Fig. 1) to adjust the flow of fluid, such as a proportional—
integral—derivative ), bang-bang, neural network, and/or fuzzy logic control
system. In this specific exemplary embodiment (i.e., an embodiment having the
infusion pump 414), the valve 6 is optional. However, in other embodiments, the
valve 6 may or may not be used, and/or is optional. The infusion pump 414 may
adjust the rotation of a cam and/or a motor in accordance with measurements from
the flow meter 7, such as flow rate, volume infused, total volume infused, etc.
Additionally or alternatively, the infusion pump 414 may stop fluid flow (e.g., by
stopping the pumping ) when the flow meter 7 communicates to the infusion
pump 414 that a free flow condition exists. In yet additional ments, the
monitoring client 8 controls the operation of the infusion pump 414 (e.g., via a
ss connection) and es feedback from the flow meter 7.
In some embodiments, the fluid oir 2 is pressurized to facilitate the
flow of fluid from the fluid reservoir 2 into the patient 3, e.g., in the case where the
fluid reservoir 2 (e.g., an IV bag) is below the patient 3; The pressurization provides
sufficient mechanical energy to cause the fluid to flow into the patient 3. A y
of pressure sources, such as physical pressure, mechanical pressure, and
pneumatic pressure may be applied to the inside or outside of the fluid reservoir 2.
In one such embodiment, the pressurization may be provided by a rubber band
wrapped around an IV bag.
The flow meter 7 and the valve 6 may form a closed-loop system to
regulate fluid flow to the patient 3. For example, the flow meter 7 may receive a
target flow rate from a monitoring client 8 by communication using transceivers 9,
. That is, the transceivers 9, 10 may be used for communication between the
flow meter 7 and the monitoring client 8. The transceivers 9, 10 may communicate
between each other using a modulated signal to encode various types of
information such as digital data or an analog signal. Some tion techniques
used may include using carrier frequency with FM modulation, using AM
modulation, using digital tion, using analog modulation, or the like.
[00275] The flow meter 7 tes the flow rate through the drip chamber 4 and
adjusts the valve 6 to achieve the target flow rate received from the monitoring
client 8. The valve 6 may be controlled by the flow meter 7 directly from
ication lines coupled to an actuator of the valve 6 or via a wireless link from
the flow meter 7 to onboard circuitry of the valve 6. The onboard electronics of the
WO 96722
valve 6 may be used to control actuation of the valve 6 via an actuator coupled
thereto. This closed-loop embodiment of the flow meter 7 and the valve 6 may
utilize any l algorithm including a PID control algorithm, a neural network
control algorithm, a fuzzy-logic control algorithm, the like, or some combination
thereof.
The flow meter 7 is coupled to a support member 17 that is coupled to
the drip chamber 4 via a coupler 16. The support member 17 also supports a
backlight 18. The backlight 18 includes an array of LEDs 20 that provides
illumination to the flow meter 7. In some specific embodiments, the backlight 18
includes a background pattern 19. In other embodiments, the backlight 18 does not
e the ound pattern 19. In some embodiments, the ound pattern
19 is present in only the lower portion of the backlight 18 and there is no
background pattern 19 on the top (e.g., away from the ground) of the backlight 18.
The flow meter 7 includes an image sensor 11, a free flow or
component 12, a flow rate estimator ent 13, a control component 14, an
exposure component 29, a processor 15, and a eiver 9. The flow meter 7
may be battery operated, may be powered by an AC outlet, may include
supercapacitors, and may include on-board, power-supply circuitry (not explicitly
shown).
[00278] The image sensor 11 may be a CCD sensor, a CMOS sensor, or other
image sensor. The image sensor 11 captures images of the drip chamber 4 and
communicates image data corresponding to the captured images to the processor
The processor 15 is also coupled to the free flow detector component 12,
the flow rate tor ent 13, the control component 14, and the exposure
component 29. The free flow detector component 12, the flow rate estimator
component 13, the control component 14, and the exposure component 29 may be
implemented as processor executable instructions that are executable by the
processor 15 and may be stored in memory, such as a non-transitory processor-
readable memory, ROM, RAM, EEPROM, a harddisk, a harddrive, a flashdrive, and
the like.
The processor 15 can e the instructions of the free flow detector
component 12 to determine if a free flow condition exists within the drip chamber 4
by analyzing the image data from the image sensor 11. s embodiments of
WO 96722
the free flow detector component 12 for ing a free flow ion are
described below. In response to a detected free flow condition, the sor 15
can make a on call to the control component 14 to send a signal to the valve 6
to completely stop fluid flow to the patient 3. That is, if the free flow or
component 12 determines that a free flow ion , the flow meter 7 may
instruct the valve 6 to stop fluid flow, may instruct the monitoring client 8 to stop
fluid flow (which may communicate with the valve 6 or the pump 414), and/or may
instruct the pump 414 to stop pumping or occlude fluid flow using an internal safety
occluder.
[00281] The flow rate estimator component 13 estimates the flow rate of fluid
flowing through the drip chamber 4 using the image data from the image sensor 11.
The processor 15 communicates the estimated flow rate to the control component
14 (e.g., via a function call). Various embodiments of estimating the flow rate are
described below. If the flow rate estimator component 13 determines that the flow
rate is greater than a predetermined threshold or is outside a predetermined range,
the flow meter 7 may instruct the valve 6 to stop fluid flow (which may communicate
with the valve 6 or the pump 414), may instruct the monitoring client 8 to stop fluid
flow (which may communicate with the valve 6 or the pump 414), and/or may
instruct the pump 414 to stop pumping or occlude fluid flow using an internal safety
occluder.
The processor 15 controls the array of LEDs 20 to provide sufficient light
for the image sensor 11. For example, the exposure component 29 may be used
by the processor 15 or in ction therewith to control the array of LEDs 20 such
that the image sensor 11 captures image data sufficient for use by the free flow
detector component 12 and the flow rate estimator component 13. The processor
may implement an exposure algorithm stored by the exposure component 29
(see Fig. 2) to control the lighting conditions and/or the exposure of the image
sensor 11 when generating the image data. Additionally or alternatively, the
exposure ent 29 may be implemented as a circuit, an integrated circuit, a
CPLD, a PAL, a PLD, a hardware-description-language-based implementation,
and/or a software system.
The control component 14 calculates adjustments to make to the valve 6
in accordance with the estimated flow rate from the flow rate estimator component
13. For example and as usly mentioned, the control component 14 may
implement a PID control algorithm to adjust the valve 6 to achieve the target flow
rate.
The monitoring client 8, in some embodiments, monitors operation of the
system 1. For example, when a free flow condition is detected by the free flow
detector component 12, the monitoring client 8 may wirelessly communicate a
signal to the valve 6 to interrupt fluid flow to the patient 3.
] The flow meter 7 may additionally include various output devices to
facilitate patient safety, such as various scanners, and may utilize the transceiver 9
to communicate with electronic medical s, drug error reduction systems,
and/or facility services, such as inventory control systems.
In a specific ary embodiment, the flow meter 7 has a scanner,
such as an RFID ogator that interrogates an RFID tag ed to the fluid
reservoir 2 or a barcode scanner that scans a barcode of the fluid reservoir 2. The
scanner may be used to determine whether the correct fluid is within the fluid
reservoir 2, it is the correct fluid reservoir 2, the treatment programmed into the flow
meter 7 corresponds to the fluid within the fluid reservoir 2 and/or the fluid reservoir
2 and flow meter 7 are correct for the particular patient (e.g., as determined from a
patient’s barcode, a patient’s RFID tag, or other t identification).
For example, the flow meter 7 may scan the RFID tag of the fluid
reservoir 2 to determine if a serial number or fluid type encoded within the RFID tag
is the same as indicated by the programmed treatment stored within the flow meter
7. onally or alternatively, the flow meter 7 may ogate the RFID tag of the
fluid reservoir 2 for a serial number and the RFID tag of the patient 3 for a patient
serial number, and also interrogate the electronic medical records using the
transceiver 9 to determine if the serial number of the fluid reservoir 2 within the
RFID tag attached to the fluid oir 2 matches the patient’s serial number within
the RFID tag attached to the patient 3 as indicated by the electronic medical
records.
Additionally or alternatively, the monitoring client 8 may scan the RFID
tag of the fluid reservoir 2 and the RFID tag of the patient 3 to determine that it is
the correct fluid within the fluid reservoir 2, it is the correct fluid oir 2, the
treatment programmed into the flow meter 7 corresponds to the fluid within the fluid
oir 2, and/or the fluid reservoir 2 is correct for the particular patient (e.g., as
determined from a patient’s barcode, RFID tag, onic medical records, or other
WO 96722
patient identification or information). Additionally or alternatively, the monitoring
client 8 or the flow meter 7 may interrogate the electronic medical records se
and/or the pharmacy to verify the prescription or to download the prescription, e.g.,
using the serial number of the barcode on the fluid reservoir 2 or the RFID tag
attached to the fluid reservoir 2.
Fig. 2 shows a flow chart diagram of a method 21 for exposing an image
sensor, e.g., the image sensor 11 of Fig. 1, in accordance with an embodiment of
the present disclosure. The method 21 includes acts 22, 23, 24, and 25. Method
21 may be implemented by the processor 15 of Fig. 1 (e.g., as the exposure
ent 29) and may be implemented as a processor-implemented method, as
a set of instructions configured for ion by one or more processors, in
hardware, in re, the like, or some combination thereof.
Act 22 selects a region of interest. For example, referring again to Fig. 1,
the image sensor 11 includes a field of view that includes the drip chamber 4.
r, the drip chamber 4 may not occupy the entire field of view of the image
sensor 11. Act 22 selects only the pixels of the image sensor 11 that show, for
example, the drip chamber 4.
Act 23 ines if a pixel is within the region of interest 23. If the pixel
of act 23 is a pixel that images, for example, the drip chamber 4, then act 23
determines that it is within the region of interest. Likewise, in this example, if the
pixel of act 23 is a pixel that does not image the drip chamber 4, act 23 determines
that the pixel is not within the region of interest.
Act 24 activates a ght, e.g., backlight 18 of Fig. 1, if the pixel is
within the region of interest. Pixels of an image sensor may be exposed during
different times. Thus, the backlight 18 may be activated only when pixels within the
region of interest are being exposed. For example, some image sensors include
vertical and horizontal sync signals. The backlight may be synchronized with these
signals to turn on when a pixel of interests is being exposed.
In some embodiments of the present disclosure, a subset of LEDs of the
backlight (e.g., a subset of the LED array 18, which may a 2-dimensional array)
may be turned on. The subset may be a sufficient subset to sufficiently nate
the pixel being d if the pixel is within the region of interest.
Act 25 exposes the pixel. If in act 23 it was ined that the pixel is
within the region of interest, the pixel will be exposed with at least a portion of the
backlight turned on in act 25. Additionally, if in act 23 it was determined that the
pixel is not within the region of interest, the pixel will be exposed without at least a
portion of the ght turned on in act 25.
Fig. 3 shows a timing m 29 illustrating an embodiment of the
method of Fig. 2 in accordance with an embodiment of the present disclosure. The
timing diagram 29 includes traces 26, 27, and 28. Trace 26 is a vertical sync signal
from an image sensor and trace 27 is a horizontal sync signal from the image
sensor (e.g., image sensor 11 of Fig. 1). A circuit or software routine (e.g., the
exposure component 29 found in the flow meter 7 of Fig. 1) may use the sync
traces 26, 27 to generate a backlight-enable signal 28 that is used to activate a
backlight or a subset thereof.
Figs. 4A-4B show rations of image data of a flow meter 7 illustrating
an embodiment of the method of Fig. 2 in accordance with the timing diagram of
Fig. 3 in accordance with an embodiment of the present disclosure. Fig. 4A
illustrates the image data taken by a flow meter, such as the flow meter 7 of Fig. 1,
t the use of the exposure algorithm illustrated in Figs. 2 and 3; Fig. 4B
illustrates the image data taken by the flow meter with the use of the exposure
algorithm illustrated in Figs. 2 and 3. Less power is needed to provide nation
during the capture of the image of Fig. 4B than to provide illumination for the
capture of the image of Fig. 4A because of less use of the backlight.
Fig. 5 shows a diagram of a flow meter 67 and a valve 71 that are
ated together for coupling to a drip chamber 409 and an IV bag 69 in
ance with an embodiment of the present disclosure. The flow meter 67
includes an optical drip counter 68 that receives fluid from the IV bag 69. The
optical drip counter 68 may be an image sensor, a pair of image sensors, a
capacitive drip counter, and/or the like. The flow meter 67 is coupled to a tube 70
coupled to a roller clamp 71 that is controlled by a motor 72. The motor 72 is
coupled to a lead screw mechanism 73 to control a roller clamp 71 via interaction
with interacting members 74.
[00298] The motor 72 may be a servo motor and may be used to adjust the flow
rate through the tube 70. That is, the flow meter 67 may also function as a flow
meter and regulator. For e, a processor 75 within the flow meter 67 may
adjust the motor 72 such that a desired flow rate is achieved as measured by the
l drip counter 68. The processor 75 may implement a control algorithm using
the optical drip counter 68 as feedback, e.g., a PID control loop with the output
supplied to the motor 72 and the feedback received from the optical drip counter
In alternative embodiments, the motor 72, the lead screw mechanism 73,
and the roller clamp 71 may be replaced and/or supplemented by an actuator that
squeezes the tube 70 (e.g., using a cam mechanism or linkage driven by a motor)
or they may be replaced by any sufficient , screw, or slider driven by a motor.
For e, in some embodiments of the t disclosure, the roller clamp 71
may be replaced by any valve as described herein, including a valve having two C-
shaped members, a valve having two curve-shaped support members, a valve
having two flexible sheets, a valve that pinches on the tube over a significant length
of the tube, or the like.
The flow meter 67 may also optionally include a display. The display
may be used to set the target flow rate, display the current flow rate, and/or provide
a button, e.g., a touch screen button to stop the flow rate.
Fig. 6 is a block diagram of an imaging system 78 of a flow meter for
g a drip chamber in accordance with an embodiment of the t
disclosure. The g system 78 as shown in Fig. 6 may be used within any flow
meter described herein, including the flow meter 7 of Fig. 1 and/or the flow meter
67 of Fig. 5.
The imaging system 78 of Fig. 6 includes an image sensor 63, a uniform
backlight 79 to shine light at least partially through the drip chamber 59, and an
ed (“IR”) filter 80 that receives the light from the uniform backlight 79.
System 78 also includes a processor 90 that may be operatively coupled
to the image sensor 63 and/or the uniform backlight 79. The processor 90
implements an algorithm to determine when a free flow condition exists and/or to
estimate a flow rate (e.g., using the free flow detector component 12 or the flow rate
estimator component 13 of Fig. 1). The sor 90 may be in operative
communication with a processor-readable memory 91 (e.g., a non-transitory
processor-readable memory) to receive one or more instructions to implement the
algorithm to determine if a free flow condition exists and/or to estimate the flow rate.
The one or more instructions from the sor-readable memory 91 are
ured for execution by the processor 90.
] The uniform backlight 79 may be an array of light-emitting diodes
”) having the same or different colors, a light bulb, a window to receive
t light, an incandescent light, and the like. In some embodiments, the
uniform backlight 79 may include one or more point-source lights.
The sor 90 may modulate the uniform backlight 79 in accordance
with the image sensor 63. For example, the processor 90 may activate the uniform
backlight 79 for a predetermined amount of time and signal the image sensor 63 to
capture at least one image, and thereafter signal the uniform backlight 79 to turn
off. The one or more images from the image sensor 63 may be processed by the
processor 90 to estimate the flow rate and/or detect free flow conditions. For
example, in one embodiment of the present disclosure, the system 78 rs the
size of the drops being formed within the drip chamber 59, and counts the number
of drops that flow through the drip chamber 59 within a predetermined amount of
time; the processor 90 may average the periodic flow from the individual drops over
a period of time to estimate the flow rate. For e, if X drops each having a
volume Y flow through the drip chamber in a time Z, the flow rate may be calculated
as (X*Y)/Z.
Additionally or alternatively, the system 78 may determine when the IV
fluid is streaming through the drip chamber 59 (Le, during a free flow condition).
The uniform backlight 79 shines light through the drip r 59 to provide
sufficient illumination for the image sensor 63 to image the drip chamber 59. The
image sensor 63 can capture one or more images of the drip r 59.
Other orientations and configurations of the system 78 may be used to
account for the orientation and output characteristics of the uniform backlight 79,
the sensitivity and orientation of the image sensor 63, and the ambient light
conditions. In some embodiments of the t disclosure, the processor 90
implements an algorithm that utilizes a uniformity of the images collected by the
image sensor 63. The uniformity may be facilitated by the uniform backlight 79.
For example, consistent uniform images may be captured by the image sensor 63
when a uniform ght 79 is utilized.
Ambient lighting may cause inconsistencies in the images ed from
the image sensor 63; for example, direct solar nation provides inconsistent
lighting because the sun may be intermittently obscured by clouds and the sun’s
brightness and angle of illumination depend upon the time of the day. Therefore, in
some ments of the present disclosure, an IR filter 80 is optionally used to
filter out some of the ambient light to mitigate variations in the images captured by
the image sensor 63. The IR filter 80 may be a narrow-band infrared light filter
placed in front of the image sensor 63; and the uniform backlight 79 may emit light
that is about the same wavelength as the center frequency of the passband of the
filter 80. The IR filter 80 and the uniform backlight 79 may have a center frequency
of about 850 nanometers. In some embodiments, the imaging system 78 may be
surrounded by a visually translucent but IR-blocking shell. In alternative
embodiments, other optical frequencies, bandwidths, center frequencies, or filter
types may be utilized in the system 78.
Fig. 7 is a graphic ration of an image 81 captured by the image
sensor 63 of the system 78 of Fig. 6 in accordance with an embodiment of the
present sure. The image 81 is an image of a drip chamber 59 having
condensation 82 and a stream 83 caused by a free flow condition therein. Edge
detection may be used to determine the position of the stream 83 and/or the
condensation 82, in some embodiments. Additionally or alternatively, a
background image or pattern may be used.
Fig. 8 is a block diagram of an imaging system 84 of a flow meter for
imaging a drip chamber in accordance with an ment of the present
disclosure. The imaging system 84 may be used with any flow meter disclosed
, including the flow meter 7 of Fig. 1 and the flow meter 67 of Fig. 5.
System 84 es an array of lines 85 that are opaque behind the drip
chamber 59. System 84 uses the array of lines 85 to detect a free flow condition.
The free flow detection algorithm (e.g., the free flow detector component 12 of Fig.
1) may use the ce or absence of drops for determining whether or not a
streaming condition (e.g., a free flow condition) exists.
In some specific embodiments, the lines 85 are only present on a fraction
of the image (e.g., the background pattern only es a fraction of the backlight
18 or the binary optics only causes the pattern to appear in a fraction of the image,
such as the lower or upper half). For example, a lower fraction of the image may
include a background pattern of stripes.
] Referring now to Fig. 9, a c illustration of an image 86 is shown as
captured by the image sensor 63 of Fig. 8 when a free flow condition exists in the
drip chamber 59 in ance with an embodiment of the present disclosure. The
WO 96722
image 86 illustrates the condition in which the drip r 59 experiences a free
flow condition and illustrates the effect that the stream of fluid 87 acts as a positive
cylindrical lens. That is, as shown in Fig. 9, the array of lines 85 as ed in an
image by the image sensor 63 are shown as a reversed line pattern 88 from the
array of lines 85 as compared to a non-free flow condition. The appearance of the
reversed line pattern 88 is caused by changes to the light when the light passes
through the stream of fluid 87 as the light approaches the image sensor 63.
In some embodiments of the present disclosure, illumination by light
having an optical wavelength of about 850 nanometers may be used to create the
image 86. Some materials may be opaque in the visible um and transparent
in the near IR spectrum at about 850 nanometers and ore may be used to
create the array of lines 85. The array of lines 85 may be d using various
rapid-prototyping plastics. For example, the array of lines 85 may be created using
a rapid-prototype structure printed with an infrared-opaque ink or coated with a
metal for making the array of lines 85. Additionally or atively, in some
embodiments of the present disclosure, another method of creating the array of
lines 85 is to create a circuit board with the lines laid down in copper. In another
embodiment, the array of lines 85 is created by laying a piece of ribbon cable on
the uniform backlight 79; the wires in the ribbon cable are opaque to the infrared
spectrum, but the insulation is transparent such that the spacing of the wires may
form the line for use during imaging by the image sensor 63 (see Fig. 8). In yet
additional embodiments, a piece of thin EDMed metal may be utilized. Metal is
opaque to light and the spaces between the metal material deposits may be very
finely controlled during manufacture to allow the IR light to pass through the
spaces.
The processor 90 implements an algorithm to ine when a free flow
condition exists (e.g., using the free flow detector component 12 of Fig. 1). The
processor 90 may be in operative communication with a processor-readable
memory 91 (e.g., a non-transitory processor-readable memory) to receive one or
more instructions to implement the algorithm to ine if a free flow condition
. The one or more instructions from the processor-readable memory 91 are
configured for execution by the processor 90.
Referring again to Fig. 8, blood may be used by the system 84. For
example, system 84 may determine when a free flow condition of blood exists when
utilizing the image sensor 63, the IR filter 80, and the uniform backlight 79
configured, for example, for use using optical light having a wavelength of 850
nanometers or 780 nanometers, e.g., when using bovine blood. The blood may
appear opaque compared to the images taken using water.
The following algorithm implemented by the processor 90 and received
from the processor-readable memory 91 may be used to determine when a free
flow condition exists: (1) establish a background image 89 (see Fig. 10); and (2)
subtract the background image 89 from the current image. Additionally processing
may be med on the resulting image.
[00318] In some embodiments of the present disclosure, the background image
89 of Fig. 10 may be dynamically generated by the processor 90. The dynamic
background image may be used to t for ng conditions, e.g.
condensation or splashes 82 on the surface of the drip chamber 59 (see Fig. 7).
For e, in one specific embodiment, for each new image captured by the
image sensor (e.g., 63 of Fig. 8), the background image has each pixel multiplied
by .96 and the t image (e.g., the most recently ed image) has a
tive pixel multiplied by .04, after which the two values are added together to
create a new value for a new background image for that respective pixel; this
process may be repeated for all of the pixels. In yet another e, in one
specific embodiment, if a pixel of the new image is at a row, x, and at a column, y,
the new background image at row, x, and column, y, is the value of the previous
background image at row, x, and column, y, multiplied by .96, which is added to the
value of the pixel at row, x, and column, y of the new image multiplied by .04.
When the system 84 has no water flowing through the drip chamber 59
(see Fig. 8) the resulting subtraction should be almost completely back, i.e., low
pixel magnitudes, thereby facilitating the algorithm to determine that the drip
chamber 59 has no water flowing therethrough.
Fig. 11 shows an image 92 from the image sensor 63 when there is a
drop within the drip chamber 59 (see Fig. 8). Fig. 12 shows a ound image
93 used by the system 84. When the system 83 has a drop as shown in image 92
of Fig. 11, the system 84 of Fig. 8 has a few high contrast-spots where the image of
the array of lines is warped by the lensing of the droplet as illustrated by an image
94 of Fig. 13. Image 94 of Fig. 13 is generated by taking, for each respective pixel,
the absolute value of the subtraction of the image 92 of Fig. 11 from image 93 of
WO 96722
Fig. 12, and converting each respective pixel to a white pixel if the value is above a
predetermined threshold or otherwise converts the pixel to a black pixel when the
value is below the predetermined threshold. Each white pixel within the image 94
of Fig. 13 is a result of there being a difference for that pixel location between the
images 92 and 93 that is greater than a predetermined threshold.
] For e, consider three respective pixels of Figs. 11, 12, and 13
having a location of row x and column y. To ine the pixel of row x and
column y for the image 94 of Fig. 13, the pixel at row x and column y of image 92 of
Fig. 11 is subtracted from the pixel at row x and column y of image 92 of Fig. 12,
then the absolute value of the result of the subtraction is taken; and if the absolute
value of the result is above a predetermined threshold (e.g., above a grayscale
value of 128, for example), the pixel at the location of row x and column y of image
94 of Fig. 13 is white, otherwise the pixel at the location of row x and column y of
image 94 of Fig. 13 is black.
[00322] When it is determined that a few high-contrast spots exist within the
image 94 of Fig. 13, the processor 90 of system 84 (see Fig. 8) determines that
drops are being formed within the drip chamber 59 and no free flow condition
exists. The images of the drops may be utilized to determine the size of the drops
to estimate a flow rate as described herein.
] Fig. 14 is a graphic representation of some of the image processing that
may be performed using Figs. 11-13 to determine if a free flow condition exists in
accordance with an embodiment of the present disclosure. Referring to Figs. 14
and 13, all of the white pixels for each row are summed together, and are illustrated
in Fig. 14 as results 183. The y-axis represents the row , and the x-axis
represents the summed number of white pixels for each tive row.
Referring now to only Fig. 14, as previously mentioned, the number of
white pixels for each row is summed together and is illustrated as results 183,
which are used to determine if or when a free flow condition exists. In some
specific embodiments, the processor 90 of system 84 (see Fig. 8) determines that a
free flow condition exists when a ermined number of contiguous values of the
summed rows of the s 183 exist above a threshold 184. For example, within
the results 183, a range of a plurality of contiguous rows represented generally by
185 have a total value above the threshold 184. When greater than a
predetermined number of contiguous summed rows are determined to exist within
the s 183 above a predetermined threshold (e.g., threshold 184), a free flow
condition is determined to exist by the processor 90 of Fig. 8. For example, as
shown in Fig. 14, the range of the plurality of contiguous summed rows 185 are
below the ermined number of contiguous summed rows (i.e., the range 185
is not wide enough) and therefore a free flow condition is ined to not exist.
Fig. 15 shows an image 95 showing a stream as captured by the image
sensor 63 of Fig 8 when a free flow condition . Fig. 16 shows a background
image 96. Fig. 17 shows an image 97 formed by the absolute value of the
difference between the image 96 of Fig. 16 and the image 95 from Fig. 15 when the
te value is converted either to a white pixel (when the absolute value of the
difference is above a threshold) or to a black pixel (when the absolute value of the
difference is below the threshold). As shown in Fig. 17, high-contrast spots caused
by the reverse orientation of the lines in the stream that run from top to bottom are
detectable by the processor 90. The sor 90 of Fig. 8 can use the image 97
to determine if a free flow ion exists using the algorithm described above.
That is, as shown in Fig. 18, results 186 are shown as having a
contiguous range 187 of the results 186 that are above a threshold 188. e
the contiguous range 187 of summed rows is greater than a predetermined
threshold number of contiguous values above the threshold 188, a free flow
condition is determined to exist by the processor 90 (see Fig. 8). That is, the
uous range of the results 186 above the threshold 188 is greater than a
predetermined threshold range of contiguous values; therefore, the processor 90
determines that a free flow condition exists when using the results 186 of Fig. 18.
In yet an additional embodiment of the present disclosure, the intensity,
the intensity squared, or other function may be used to produce the results 183 of
Fig. 14 and/or results 186 of Fig. 18. In yet an additional embodiment, one or more
data smoothing functions may be used to smooth the results 183 and/or 186, such
as a spline function, a cubic spline function, a B-spline function, a Bezier spline
function, a polynomial interpolation, a moving average, or other data smoothing
function.
For example, an image of the image sensor 63 of Fig. 8, e.g., image 95
of Fig. 15, may be subtracted from a background image, e.g., the image 96 of Fig.
16, to obtain intensity values. That is, a pixel of row x and column y of Fig. 15 may
be subtracted from a pixel of row x and column y of the image 96 of Fig. 16 to
create an intensity value at row x and column y; this may be repeated for all pixel
locations to obtain all of the intensity values. The intensity values of each row may
be summed er to obtain the results 183 and/or 186 (see Figs. 14 and 18,
respectively), such that the processor 90 may determine that a free flow condition
exists when the summed rows of the ity values has a contiguous range of
summed rows above a threshold. In some embodiments, the intensity values are
converted to te values of the intensity values, and the summed rows of the
absolute values of the intensity values are used to determine if a contiguous range
of summed rows of the absolute values is above a threshold range of contiguous
values. Additionally or alternatively, the intensity may be squared and then the
processor 90 may sum the squared intensity rows and ine if a contiguous
range of summed rows of the intensity squared values exists beyond a threshold
range of uous values to determine if a free flow condition exists.
In some embodiments, a predetermined range of contiguous values
above a threshold (e.g., min and max ranges) of the summed rows of intensity
values or ity squared values may be used by the sor 90 to determine if
a drop of liquid is within the image. For example, each row of the rows of the
intensity values (or the intensity squared values) may be summed together and a
range of the summed values may be above a threshold number; if the range of
contiguous values is n a minimum range and a maximum range, the
processor 90 may determine that the range of contiguous values above a
predetermined threshold is from a drop within the field of view of the image sensor
63 (see Fig. 8). In some embodiments of the t disclosure, the summed rows
of intensity values or intensity squared values may be ized, e.g., normalized
to have a value between 0 and 1.
The following describes a smoothing function similar to the cubic spline
(i.e., the cubic-spline-type function) that may be used on the summed rows, the
summed rows of intensity values, or the summed rows of the intensity values
squared prior to the determination by the processor 90 to determine if a free flow
condition exits. In some specific embodiments, the cubic-spline-type function may
be used to identify blocks, as described infra, which may facilitate the processor’s
90 identification of free flow conditions.
The cubic-spline-type function is an analog to the cubic , but it
smoothes a data set rather than faithfully mimics a given function. Having data
2012/071142
sampled on the interval from
[0’1]
(e.g., the summation along a row of intensity
squared or intensity that is normalized) the processor 90 (see Figs. 6 or 8) may find
the best fit set of cubic functions on the intervals [xo’x1]’[xl’x2]"'"[xN—l’xN] with
x0=0 =1 and xN where the total function is continuous with uous derivatives
and continuous curvature.
The standard cubic spline tion is illustrated in Equation (1) as
follows:
Z(x)zAi(x)yi+Bi(x)yi+1+Ci(x)yi”+Di(x)yi:1 xigxgxifl
(1),
with the functions Ai’Bi’Ci’Di defined as in the set of Equations (2):
Ai(x)=xi+1_x=xi+l_x, "x—xi
Bi: :x_xi
xi+1 _ xi Ai xi+1 _ xi Ai
Cix=—i()NM)Ai x—Aix()), Dl.=—iA2M)Bl. x—Bix())
[00335] 6 6 (2).
The Equations (1) and (2) guaranty continuity and curvature continuity.
The only values which can be freely chosen are yo
y,-, and yN. Please note that
Equation (3) is chosen as follows:
yO : yl : 0
(3),
[00338] Le, the function is flat at 0 and 1. The remaining yi must satisfy the
following set of Equations (4):
yi-yo yon _ yz-y1 yfAi yé'Ai
+ _
A0 3 A1 3 6
yz-y1 yfAi yZAi y3-y2 yZAz yg’Az
+ + : _ _
A1 6 3 A2 3 6
y3—y2 ygAz V312 y4—y3 yg'A3 Mir/A3
+ + : _ _
A2 6 3 A3 3 6
yN—2_yN—3 yz’HAm yXf—ZAN—3 _ N—2 yE'HAN—2 yw—lAN—z
+ + _ _
AN_3 6 3 AN_2 3 6
yN—1_yN—2 AN—z yIIv—lAN—z _ 1 AN—l
+ +
6 3 3
AN-Z A“ (4)-
The set of Equations (4) can be rewritten as the set of Equations (5) as
follows:
(5)-
In turn, this becomes the matrix Equation (6):
e o o 0 0 y:
A1 A1+A2 A2 ,,
? 3 T 0 0 0
0 % ATS 0 0 0 y;
0 0 0 AN74:AN73 A2273 0 y;_3
0 0 0 A2273 AN73:AN 2 A2272 y;_2
0 0 0 0 A2272 AN 2‘3"AN 1 37:74
_ _ Yo
to mtg-t t 0 0 0
0 AL “Ll—i 0 0 0
0 0 AL 0 0 0
0 0 0 AN: 0 0 yN_3
0 0 0 1N: — AL AL 0 yN_2
0 0 0 A1 —A1 — A1 A1 yN—l
YN (6)
The matrix Equation (6) may be rewritten as the set of ons (7) as
follows:
FYdd : Gy
_ _
ydd — F Gy — Hy (7).
Choosing the values in the vector y using a least squares ion on the
collected data is shown in Equation (8) as follows:
EZZ|:y/k—Aik()y§k—Bik(5k)yik+1—Cik(5k)yi:—Dik(fk)yi::| (8).
2012/071142
Equation (8) is the minimum deviation between the data and the ,
i.e., on (8) is an error function. The y values are chosen to minimize the error
as defined in Equation (8). The vector of predicted values can be written as
illustrated in Equation (9) as follows:
I? 2 (Am + B{k} )y + (Cm + D{k} WM
2 (Am +B{k} )y + (Cm + D{k} )Hy
= [Am +13%} +D{k}H]y
= Ay
(9).
The elements of the matrix in ts of Equation (9) depend upon the
X-value corresponding to each data point (but this is a fixed matrix). Thus, the final
equation can be determined using the pseudo-inverse. In turn, the pseudo-inverse
only depends upon the x-locations of the data set and the locations where the
breaks in the cubic spline are set. The implication of this is that once the geometry
of the spline and the size of the image are selected, the best choice for y given a
set of ed values ym is illustrated in Equation (10) as follows:
y = (AT A) A - ym
(10).
The cubic spline through the sum intensity-squared function of the image
will then be given by Equation (11) as follows:
yCS = A. y
(11).
Because the maximum values of the cubic spline are of interest, the
tive of the cubic spline is determined and utilized to determine the maximum
values of the cubic spline. The cubic spline derivative is given by Equation (12) as
follows:
Z/(xk) :A', (xk)y' +3, (xk)yik+1+Ci; (xk)yi: +Di; (xk)yi:+1
., ,. (Meow—03%;“(33500—1)
ik ik (1 2).
Equation (12) can be written as Equation (13) as follows:
ygs Z (Atki + Bik} ) y + (Cf/c} + DEk} )ydd
= {Abe} +39.) +CEk}H +DEk}H]y
2 A/y
(13).
Once the current values of y are found, the cubic spline, yes, and its
derivative, y’cs, can be calculated. The cubic spline data may include “blocks” of
data that includes values above a predetermined threshold. A pipe block is formed
by the liquid flowing out of the tube into the drip chamber 59 and a pool block is
formed as the liquid collects at the gravity end of the drip chamber 59 (see Fig. 8).
The following algorithm may be applied to the cubic spline data: (1)
determine the local maxima of the cubic spline data using the derivative
information; (2) determine the block surrounding each local maxima by ing all
points where the cubic spline value is above a threshold value; (3) merge all blocks
which intersect; (4) calculate information about the block of data including the
center of mass (intensity), the second moment of the mass (intensity), the lower x-
value of the block, the upper x-value of the block, the mean value of the original
sum of intensity squared data in the block, the standard deviation of the original
sum of ity d data in the block, and the mean intensity of a ass
filtered image set in the block; and (5) interpret the collected data to obtain
ation about when drops occur and when the system is ing.
The mean intensity of a high-pass filtered image set in the block is used
to determine if the block d by each contiguous range of spline data is a result
of a high frequency artifact (e.g., a drop) or a low frequency artifact. This will act as
a second background filter which tends to remove artifacts such as condensation
from the image. That is, all previous images in an image memory buffer (e.g., 30
previous frames, for e) are used to determine if the data is a result of high
frequency movement between frames. If the block is a result of low ncy
changes, the block is removed, or if it is a result of high frequency changes, the
block is kept for further analysis. A finite impulse response filter or an infinite
impulse response filter may be used.
Each block is plotted over its physical extent with the height equal to the
mean value of the data within the block. If a block has a mean value of the high-
pass filtered image less than the threshold, it is an tion that it has been
around for several images and thus may be removed.
] Free flow ions may be determined by the sor 90 (see Figs. 6
or 8) to exist using the blocks when the pipe block extends nearly to the pool block,
the pipe block and the pool block merge together, and/or the summed range of
widths of the pool and pipe blocks (or all blocks) is greater than a predetermined
old, e.g., the total extent of the blocks s 380 pixels in width. The
processor 90 may detect a drop when the transition of the pipe block from a larger
width to a shorter width occurs as a result of a drop formation in the tube and as the
drop leaves the pipe (i.e., tube) g of the drip chamber 59. The processor 90
may detect this by looking at the ratio of the current pipe block width to the previous
image’s pipe block width, e.g., an image where the ratio is less than 0.9 as is also a
local minima may be considered by the processor 90 to be an image formed
immediately after a drop has formed.
[00362] Various filtering algorithms may be used to detect condensation or other
low frequency artifacts, such as: if a block has a low mean value in the high-pass
filtered image, then it may be condensation. This artifact can be removed from
consideration. Additionally or alternatively, long blocks (e.g., greater than a
predetermined threshold) with a low high-pass mean value are possibly streams
because stream images tend to remain unchanging; the processor 90 may
determine that long blocks greater than a predetermined threshold corresponds to
a streaming condition. Additionally or alternatively, an algorithm may be used on
the current image to detect free flow conditions.
The processor 90 may, in some specific embodiments, use the block
data to count the drops to use the system 84 as a drop r. The processor 90
may also use width changes in the pool block as a drop disturbs the water to
determine if a bubble formed with the drop hits the pool. For example, the
processor 90 may determine that blocks that form below the pool block are from
bubbles that formed when the drop hit the water. The bubble may be filtered out by
the processor 90 when determining if a predetermined value of total block ranges
tes that a free flow condition exists.
In some embodiments of the present disclosure, the depth of field of the
system 84 may have a narrow depth of field to make the system 84 less sensitive to
condensation and ts on the chamber walls. In some embodiments, a near
focus system may be used.
Referring now to Fig. 19, in another embodiment of the present
disclosure, a template 189 is used to determine if a free flow condition exists. The
te 189 is used by the processor 90 of Fig. 8 to determine a pattern match
score 190 when performing a template match algorithm on an image, e.g., the
image 94 of Fig. 13. For example, the te 189 may be compared to the image
94 to determine if a portion or all of the image 94 closely matches the template 189.
As previously mentioned, the image 94 of Fig. 13 is a ence between a
background image and an image captured by the image sensor 63 of Fig. 8 that
has each pixel converted to either a black pixel if the difference value for that pixel
is below a threshold value or a white pixel if the difference value for that pixel is
above a threshold value. All pixels of the image 94 will be either a white pixel or a
black pixel. If the pattern match score 190 is above a ermined threshold, a
free flow condition is determined to exist. The template matching method may
utilize a template matching algorithm as found in the Open Source Computer Vision
(“OpenCV”) library. For example, the template 189 may be used with the
matchTemplate() function call of the OpenCV library using the CV_TM_CCOEFF
method or the method of CCOEFF_NORMED. The CV_TM_CCOEFF
method uses the pattern matching thm illustrated in Equation (14) as follows:
11.13:..111zz111x 11x~—x111—1.; 1:1
1I ,(14), where.
T1116111—_ 11..1111 ----- 1.1110 111 . E... Ti}:21
1 1x —:— x.131 + 11:1 2 11K + 91.1.1; +11 1— 1;111.111: 1EM 11:1: +£11.11 +1.:“1
; The 1 denotes the image, the T denotes the template, and the R denotes the
results. The summation is done over the template and/or the image patch, such
that: x'=0...w—1 and y'=0...h—1.
The results R can be used to determine how much the template T is
matched at a particular location within the image l as determined by the algorithm.
The OpenCV template match method of CV_TM_CCOEFF_NORMED uses the
pattern matching algorithm illustrated in Equation (15) as follows:
_ , EA. 1:111:13 1.1"] 1.. 1’13); —_§— 1:".1 +11113 J-
Rafi“:
“ $16.11 1 1}: + K.:11+ 1.11—
[00369] 1511;21:111‘ 1:111:11; (16)
In another ment of the present disclosure, the template matching
algorithm uses a Fast Fourier Transform (“FFT”). In some embodiments, any of the
methods of the matchTemplate() function of OpenCV may be used, e.g.,
CV_TM_SQD|FF, CV_TM_SQD|FF_NORMED, CV_TM_CCORR, and/or
CV_TM_CCORR_NORMED.
The CV_TM_SQD|FF uses the pattern ng algorithm illustrated in
Equation (17) as follows:
I II)? = II'1 __ III ~F— I II I- II5112
I (1 7).
CV_TM_SQD|FF_NORMED uses the pattern matching algorithm
illustrated in Equation (18) as follows:
Eff§P{:3I I:. ,I":1—— I": r: I
R11; If} :-
.- ,I‘ZI' III” I“‘ .
II III ' MW ‘ * -‘ (18).
CV_TM_CCORR uses the pattern matching algorithm illustrated in
Equation (19) as follows:
I II (1 9).
] CV_TM_CCORR_NORMED uses the pattern matching algorithm
illustrated in Equation (20) as follows:
“T‘ f1"- I113: —~— 15"}; —§« I31}
I '12
4 I!“ V “3‘ f{‘13}? \ID
“q “‘1 1r“ j-{L‘E + :33!“ 3b} + .
_ I
1.: w I II M = (20).
In yet r embodiment of the present disclosure, a template of a
grayscale image of a free flow ion is compared to an image taken by the
image sensor 63 of Fig. 8 to determine if a free flow condition exists. In some
embodiments, the template matching function within the OpenCV y may be
utilized.
Refer now to Figs. 20 and 21; in yet an additional embodiment of the
present disclosure, the algorithm to determine when a free flow condition ,
e.g., as executed by the processor 90 of Fig. 8, may utilize an algorithm to
determine if a te pattern matches an array of pixels utilizing edge detection
followed by line detection. As shown in Fig. 20, an image 98 is formed from an
image 99 of Fig. 21, by using edge detected followed by line detection. The
resulting lines may be utilized by the processor 90 to determine that a free flow
condition exists. As shown in Fig. 20, the feature which shows up after this
processing by the processor 90 are lines that have a different slope than the
expected pe of the background reference image. The lines having the angle
of the ound image may be filtered out of Fig. 20, in some embodiments. The
lines may be detected as edges using a Canny algorithm as found in the OpenCV
library. The Hough thm also found in the OpenCV library may be used to
determine the slope of the lines.
One type of Hough er uses an algorithm described in Progressive
Probabilistic Hough Transform by J. Matas, C. Galambos, and J. Kittler in 1998
(“Algorithm 1”). However, the following “Alternative Hough” transform may be
utilized and is shown in pseudo code form in Table 1 (“Algorithm 2”). Algorithm 2
selects two pixels at random and calculates the Hough transform of the line passing
through these two points. Algorithm 2 is shown in Table 1 as follows:
Table 1
Alternative Hough Transform Pseudocode
1. If the image is empty, then exit.
2. ly select two pixels and update the accumulator
a. ed Operations
i. Two random numbers
ii. One inverse tangent
3. Check if the new location is higher than the threshold /. If not, goto 1
a. Operations
i. One logical operation
4. Look along a corridor specified by the peak in the accumulator, and find
the longest segment of pixels either continuous or exhibiting a gap not
exceeding a given threshold.
. Remove the pixels in the segment from the input image.
6. Unvote from the lator all the pixels from the line that have
previously voted.
7. If the line segment is longer than the minimum length add it to the output
list
8. Goto 1.
If the line comprises a proportion, p, of the total , then the likelihood
that we will see a result in the representative bin is p for Algorithm 1 and p2
for Algorithm 2. Generally, in some embodiments, a proportion test has at least 5
positive results and 5 negative results. Assuming that it is more likely to see
negative results than positive results, in some embodiment, the Algorithms 1 and 2
continue to search for lines until there are at least 5 positive results in a ular
bin.
The probability of seeing a fifth positive result in Algorithm 1 after N25
tests is shown in on (21) as follows:
. (N—1)!
p1(50nN)=p(41nN—1).p=mp(1_p)N—55 (21),
and the probability in Algorithm 2 is shown in Equation (22) as follows:
(N—1)!
)lp10(1—p2)N—5 [00386] p2(5011N)—P(41nN._ _ 1) P_ 2_— (22).
-4!(N_5
Table 2, shown below, shows the number of tries to have a 50% chance
of seeing 5 successes, p150 and p250, as well as the number of tries to have a 90%
chance of seeing 5 successes, p190 and p230.
TABLE 2
p p1,50 p1,90 p2,50 p2,90 r50 r90
0.5 9 14 20 31 2.22 2.21
"025'""""""""i""""""1'9"""""""i"""""3'0"""""" """""" """"""""""""ii""""""L""""ii"2'3""""""
76 127
""""""""""""""" """""""""""" """"""""""" """""""""""" """"""""
"012% 3''9' 62 2'95 '5'11767 2'24"""""
0.0625 76 127 1197 2046 15.75 16.11
Table 2 shows that the increase in the number of tries between Algorithm
1 and Algorithm 2 to see 5 positive s is approximately%). There should be 1
positive result in %) trials when the proportion is p.
2012/071142
Algorithm 2’s computationally expensive operation is, in some
ments, the arc tangent function, which may be about 40 floating point CPU
operations. There are approximately 2N floating point operations in Algorithm 1’s
equivalent step. The Hough orm of a 640x480 pixel image with full resolution
has Nequal to 2520, while the Hough transform of a 1080x1920 pixel image has N
equal to 7020. This implies that Algorithm 2 has a speed advantage over Algorithm
1 when p is greater than 0.008 for a 640x480 image and when p is greater than
0.003 for a 1080x1920 image.
In some embodiments, it is assumed that every bin in the Hough
transform space is equally likely to be occupied in the presence of noise. This
simplification speeds up the olding decision; however, in some embodiments,
this assumption is not true. The y effect of the simplification is to
underestimate the probability that is seen in values greater than one in the Hough
transform with a corresponding likelihood of falsely declaring that a line . For
a particular combination of image size and Hough transform bin arrangement, the
true probabilities can be pre-computed. This allows the false alarm rate to be
minimized without a corresponding increase in computation. With additional
restrictions on the type of imagery even more accurate estimates of the probability
of seeing a value in a bin of the Hough transform is possible.
[00391] There are additional forms of the Hough transform which parameterizes
different features. For example, there is a element parameterization of
circles,(x,y,r), where x and y specify the center and r is the . Algorithm 2
can work using these parameterizations as well. For the circle example, Algorithm 2
would select three pixels at random and calculate the circle passing through them.
[00392] Algorithm 2 would have a similar speed advantage for features
comprising a suitably large portion of the total pixels considered. It would also have
a significant advantage in storage required, since the Hough transform could be
stored in a sparse matrix, while the Algorithm 1’s analog would require a ize
matrix.
[00393] Referring now to Figs. 22-26, which illustrate various ound
ns that may be used to detect a free flow condition or estimate the size of a
drop of liquid. The image sensor 103 may be used with the background patterns of
Figs. 22-26 and may be the image sensor 11 of Fig. 1, the image sensor 68 of Fig.
, the image sensor 63 of Fig. 6, or the image sensor 63 of Fig. 8, each of which
may be coupled to a respective processor for processing the images from the
image sensor, such as the processor 15 of Fig. 1 or the sor 90 of Fig. 8.
Fig. 22 is a block diagram of an imaging system 100 for use with the drip
chamber 104 (e.g., a drip r 4 of Fig. 1) having a background pattern 101
with stripes and a light source 102 shining on the stripes from an adjacent location
to an image sensor 103 in accordance with an embodiment of the present
disclosure. Any drops or free flow streams within the drip r 104 distorts the
image taken by the image sensor 103. A processor coupled to the image sensor
103 (e.g., processor 15 of Fig. 1) can use the distortions of the background pattern
101 as ed by the image sensor 103 to te a flow rate and/or detect free
flow conditions.
Fig. 23 is a block diagram of an imaging system 105 for use with the drip
chamber 104 having a background pattern 101 with stripes and a light source 102
shining on the stripes from behind the background pattern 101 relative to an
opposite end to an image sensor 103 in accordance with an embodiment of the
present disclosure. Fig. 24 shows an image from the image sensor 103 of Fig. 23
when a drop distorts the background pattern 101 of Fig. 23 in ance with an
embodiment of the present disclosure. Note that as shown in Fig. 24, the
background n’s 101 stripes are distorted by a drop (or will be distorted by a
free flow stream) in the drip chamber 104 as captured in images by the image
sensor 103. This distortion may be used to estimate the drop size, to calculate the
flow rate h a drip chamber, or to determine if a free flow condition exists
within the drip chamber.
[00396] Fig. 25 shows a block diagram of an imaging system for use with a flow
meter having a background pattern with a checkerboard pattern and a light source
shining on the stripes from behind the background pattern relative to an opposite
end to an image sensor in accordance with an ment of the present
disclosure. Fig. 26 shows an image from the image sensor of Fig. 25 when a drop
distorts the background pattern 107 of Figs 25-26 in accordance with an
embodiment of the present disclosure. In yet r embodiment of the present
disclosure, a ound pattern having a plurality of random dots and/or circles
may be utilized by an imaging system disclosed herein.
Referring to Figs. 22-26, the “lensing” of a drop (i.e., the distortion of the
background pattern from the view of an image ) may be used to measure the
radius of the drop. The radius of the drop corresponds to how much and what
effect the drop has on any light passing through it. By measuring the change to the
calibration grid (i.e., the ound pattern) as seen through the drop, the radius,
and hence the volume of the drop, can be ated. For example, the
ication of a test grid of known size as seen through the drop could be
ed optically and the radius inferred from this measurement. In some
ments of the t disclosure, the relationship between the radius and the
drop may be calculated and/or may be determined using a lookup table that has
been generated empirically.
Figs. 27-28 show a flow chart diagram illustrating a method for estimating
a volume of a drop within a drip chamber in accordance with an embodiment of the
present sure. That is, Figs. 27-28 illustrate a method 214. Method 214 will
be also described with reference to Figs. 29-37. Figs. 29-31 and 33-36 illustrate
images used or generated by a flow meter to estimate a volume of a drop within a
drip r in accordance with an embodiment of the present disclosure. Figs.
32 and 37 illustrate pseudo code that may be used by the method 214 of Figs. 27-
[00399] The method 214 of Figs. 27 and 28 may be implemented by the flow
meter 7 of Fig. 1, the flow meter 67 of Fig. 5, the imaging system 78 of Fig. 6, the
imaging system 84 of Fig. 8, or other flow meter of an imaging system disclosed
herein (each with or without a background pattern and/or with or without active
illumination).
[00400] The method 214 includes acts 200-213. Act 200 determines a baseline
of a drop forming at an opening of a drip chamber. Act 201 captures a first image.
The first image may be captured using a uniform backlight. In some embodiments,
the first image may be captured using a background pattern and/or an exposure
algorithm as described herein. Acts 200 and 201 may be performed
simultaneously. Fig. 29 shows an image with the baseline 215 overlaid. The
baseline 215 may be a predetermined group of pixels or may be generated using
fiducial markers ed on the opening of the drip chamber and/or on a
background pattern (not shown in Fig. 29). The first image is used by the method
214 to initialize a background image, [1”, a ce array, St], and an integer array,
IL]. The background image may have i byj pixels, while the variance array and the
integer array may be 2-D arrays that also have a size of i by j.
Act 202 identifies the drop within the first image and a predetermined
band near an edge of the drop (e.g., the band may be a predetermined number of
pixels beyond the edge of the drop). Act 203 initializes a background image by
setting each pixel to the same value as the first image (for that respective location)
unless it is within the identified drop or a predetermined band near the edge of the
drop. Act 204 sets pixels within the region of the drop or within the predetermined
band to a predetermined value. Fig. 30 shows an example background image
created after initialization. In the exemplary image of Fig. 30, the area of the drop
and of a band beyond the edge of the drop, designated generally as 216, is set to a
predetermined value, e.g., 140.
] For example, when the method creates the first background image, every
pixel in the background image that is part of the drop or a band outside of an edge
of the drop is set to a default threshold value, e.g. 140 out of an intensity range of
0-255.
Act 205 initializes the integers of the array of integers to zeros. Act 206
initializes the values within the array of variances to zeros. The integer array is the
same size as the image. The integer array counts how often each pixel of the
background image has been d with new information and is initialized to all
zeros. The array of ces (e.g., an array of the data type “double”) is also the
same size as the background image and contains an estimate of the variance of
the intensity of each pixel within the background image.
[00404] Act 207 captures another image and act 208 identifies the drop in the
another image and r ermined band near an edge of the drop. Act 209
updates the background image, the array of integers, and the array of ces.
As additional images are captured, the ound image may be
updated. For example, when an image is collected by the system, the background
algorithm evaluates every pixel. If a pixel is considered part of the drop or its guard
band, then its value in the ound image is not altered.
If a pixel is not considered part of the drop or its guard band: (1) if the
pixel’s corresponding integer in the integer array is zero, the pixel’s value in the
background image is set equal to the pixel’s value in the input image; or (2) if the
pixel’s count is greater than 0, then the background image value for that pixel is
updated using a low pass filter. In some embodiments, any style of filter may be
used, such as a high pass filter, a ss filter, etc. One low pass filter that may
be used is rated in Equation (23) as follows:
Pbackground,i,j : Pbackground,i,j (1 _ round ) + abaCkgroundPinput,i,j
(23)
] In addition, the variance array may be updated using Equations (24) as
follows:
—(P 2
0'2 — P
temp backgroundj ,j inputj ,j )
2 2 2
abackgroundj ,j : o-background,i ,j (1 _ IBbackground ) + I6background o-temp
(24).
[00410] Note that the filter used for both operations is an exponential filter;
however, in additional embodiments, other le filters may be used, such as
other low-pass filters. The ce estimate can be performed in any known way
or using a stand in for the estimate, e.g., using standard deviation.
The new estimates of each pixel’s background intensity (mean value), the
number of images used to update each pixel’s mean and variance, and each pixel’s
variance (e.g., an approximation to the true variance and/or a value that is
tional to the variance) are used to update the arrays. That is, each additional
image captured may be used to update the background image, the array of
integers, and the array of variances. After several images have been processed,
the background image may appear as Fig. 31. Note that this image still has a
region (the uniformly medium gray area, ated generally as 217) where the
pixels have never changed from the initial threshold value. This region has been
considered part of the drop or its guard band in every image.
Act 210 compares the another image (e.g., current or most recent image)
to the background image and identifies a plurality of pixels of interest. Act 211
determines a subset of pixels within the plurality of pixels of interest that
corresponds to a drop.
The comparison of act 210 compares the another image pixel-by-pixel to
the background image. Out of this comparison comes an array the same size as
the image where every pixel has a value of zero or not zero (255).
Act 210 may be implemented by the pseudo code shown in Fig. 32. That
is, the determination of this threshold value is made in accordance with the
following: If the input pixel is to the left or right of the baseline in the image, then its
output value is set to zero (Line 1); if the input pixel’s background count array
tes that fewer than a pre-determined number of images (e.g., 100) have been
used to make this pixel’s background value (Line 2), then: if the input pixel’s
intensity is less than the threshold intensity (e.g., 140 in a range of 0-255), then set
the pixel’s output value to not-zero (255) (Line 2a); or if the input pixel’s intensity is
greater than or equal to the threshold intensity, then set the pixel’s output value to
zero (Line 2b); and if the input pixel’s background count array is greater than the
pre-determined number of images (Line 3), then: if the square of the difference
between the input pixel intensity and the background pixel intensity is greater than
the pixel’s estimate of background variance times a constant 72, then set the
pixel’s output value to not-zero (255) (Line 3a) (that is, if the difference between
current pixel value and the background image is more than 7, then the pixel is
distinct); or if the square of the difference between the input pixel intensity and the
background pixel intensity is less than or equal to the pixel’s estimate of
background variance times a nt 72, then set the pixel’s output value to zero
(see Line 3b). Line 3 captures portions of the image that are altered by the
ce of a drop, but which are made a higher intensity.
When act 210 is implemented as an algorithm, the algorithm is initialized,
the input and output of this thresholding algorithm will look like the images in Figs.
33 and 34, respectively. e the number of images used in estimating the
background image is initially small, the only criterion applied are shown as lines (1)
and (2) above because there have not been enough images used for the integer
array to have a value beyond the threshold for certain respective pixels. This may
result in many low-intensity s being identified as distinct, including poorly
illuminated edges and condensation on the r walls.
After enough images have been gathered such that most (or all) of the
pixels of the ound image have been ted with a sufficient number of
pixels, lines (3), (3a), and (3b) of Fig. 32 are utilized. After olding, the
ound is largely black with an occasional noisy pixel exceeding the variance
threshold, as shown in Figs. 35 and 36 (which show an image captured by the
camera and the results of the comparison algorithm described above, respectively).
] As previously mentioned, after act 210, act 211 determines which of a
subset of pixels within the plurality of pixels of interest corresponds to a drop. Act
211 may be implemented by the pseudo code shown in Fig. 37. That is, the
threshold image is passed to an algorithm which finds the connected component
representing the drop as illustrated by the pseudo code of Fig. 37.
The binary image after processing the pseucode of Fig. 32 is evaluated
to find the binary component which occupies the space given by the drop. The
algorithm is passed the location of a pixel on the baseline which is white (or it is
passed the center pixel of the longest stretch of contiguous white pixels on the
line).
Once the algorithm has an initial white pixel, it performs the algorithm
illustrated by the pseudo code shown in Fig. 37. The pseudo code ines
ons that include white pixels that have a path to the baseline (Le, a white
pixel path). Line 1 pushes the location of the first pixel onto a stack. Line 2
ms a while loop while the stack is not empty. The while loop includes lines
(2a)-(2d). Line 2a pops the next location (1’1) off of the stack. Line 2b makes the
value at (1’1)
output pixel white. Line 2c examines the eight pixels adjacent to
(1’1). Line (2ci) is an “if statement” and if the adjacent input pixel (up) is white, but
the output pixel (up) is black, line 2c adds the location (up) to the stack. Line 2d
return to line 2 to continue the while loop (if the stack remains empty).
] This algorithm will set to white all output pixel ons which can be
connected to the input pixel’s location by a continuous path of white input pixels.
The left ry of the drop is found by ng through each row of pixels from
the left edge until the algorithm hits a white pixel. The right boundary is found by
stepping from the right edge of the image until it hits a white pixel. The first row
where it is possible to step from the left edge to the right edge without hitting a
white pixel is where the drop is considered to end.
[00421] The pseudo code shown in Fig. 37 is a one-pass version of a connected-
component labeling algorithm. However, other connected-component labeling
algorithms or other suitable algorithms may be used to determine which pixels
correspond to the drop.
Act 212 of Fig. 28 performs a rotation operation on the subset of pixels.
Act 213 estimates a volume of the drop within the drip chamber by counting the
number of pixels within the rotated subset of pixels. The total number of pixels
within the 3-D version of the drop is counted; and e each pixel corresponds
to a distance, the number of pixels may be used to estimate the volume of the drop.
Imaging System Optics
Figs. 38—42 facilitate the following description of the optics of an imaging
system disclosed herein. For example, an image sensor disclosed herein may be
an image sensor cube manufactured by OmniVision of 4275 Burton Drive, Santa
Clara, California 95054; and, for example, the image sensor cube may be one
manufactured for phone image sensor applications. In some embodiments of the
present disclosure, an image sensor sed herein may use a fixed focus and
have a depth of field (“DOF”) from 15 eters to infinity.
The image sensor may have the blur circle of a point imaged in the range
of the image sensor entirely contained within the area of a single pixel. The focal
length of the image sensor lens may be 1.15 millimeters, the F# may be 3.0, and
the aperture of the lens of the image sensor may be 0.3833 millimeter. A first order
approximation of the optical system of one or more of the image sensors may be
made using matrix equations, where every ray, r, is represented as the vector
described in on (25) as follows:
F = {E} (25).
In on (25) above, h is the height of the ray at the ce to the
image sensor, and 0 is the angle of the ray. Referring to Fig. 38, when imaging a
hypothetical point at a distance dim from the lens of one of the image sensors
(which has focal length f) and the lens is a distance dfp from the focal plane, the
corresponding matrix, Mcalm ,describing the image sensor is described by Equation
(26) as follows:
01—7101112”1 d 1 0 1 d.
M = fP ' 1 . ‘m
[00427] cam
2012/071142
To find the place on the focal plane, fp, where the ray strikes, a matrix
multiplication as described in Equation (27) as follows may be used:
fi= M . hi_m
g cam 49. (27)-
fp W
As illustrated in Fig. 38, the diameter of the blur circle, Dblur, is shown as
approximately the distance between the two points illustrated in Fig. 38. This
distance is found by tracing rays from the point dim away from the lens on the
optical axis to the edges of the lens and then to the focal plane. These rays are
given by the vectors shown in (28) as follows:
1 Dlens
i tan_ (28).
2*d.
[00432] As shown in Fig. 39, the blur circle, Dblur, is calculated and shown for a
variety of o-focal plane tions and lens-to-image separations. A contour
map 77 is also shown in Fig. 39. The x-axis shows the distance in microns
n the focal plane and a point located a focal length away from the lens of an
image sensor. The y-axis shows the distance in meters between the lens and the
point being imaged. The values creating the contour map 77 is the blur size
divided by the pixel size; therefore anything about 1 or less is ient for imaging.
As shown in Fig. 39, the focal plane is located a focal length and an additional 5
micrometers away from the lens.
] The image sensor may utilize a second lens. For example, an image
sensor may utilize a second lens to create a relatively larger depth of field and a
relatively larger field of view. The depth of field utilizing two lenses can be
calculated using the same analysis as above, but with the optical matrix modified to
accommodate for the second lens and the additional distances, which is shown in
Equation (29) as follows:
O O
1 1 1 d-
= dfP 11 11
- d1 __ 1 . ens . . 1m
_ 1
sys 0 1 f 0 1 f 0 1 (2
cam lens
Figs. 40 and 41 rate the field changes with the separation between
the lens and the image sensor and the corresponding change in the focus of the
image sensor. Figs. 40 and 41 show the blur circle d by the pixel size. Fig.
40 shows the blur circle d by pixel size when a 20 millimeter focal length lens
is used. Fig. 41 shows the blur circle divided by pixel size when a 40 millimeter
focal length lens is used. The corresponding fields of views about the optical axis
for the corners of the two configurations of Figs. 40 and 41 are shown in the table in
Fig. 42.
As shown in Fig. 42, in some embodiments, the image sensor may utilize
a 40mm to 60mm focal length lens; this configuration may include placing an image
sensor about 2 inches from the focus. In other embodiments of the present
disclosure, other configurations may be used ing those not shown in Fig. 42.
For example, the following analysis shows how the depth of field can be
set for an image sensor: using a lens of focal length, f, a distance, 2, from the focal
plane, and a distance, d, from a point in space; a matrix of the system is shown in
Equation (30) as follows:
1 1 0
Z 1 d
M: . _1 .
0 1 1 (30).
f 0 1
Equation (30) reduces to Equation (31) as follows:
1 1 d
M: - _i 1—1 (31).
[00441] Equation (31) reduces to Equation (32) as follows:
Li aim—£—
M: 1f df (32).
f7 ‘7
ering the on-axis points, all of the heights will be zero. The point
on the focal plane where different rays will strike is given by Equation (33) as
follows:
[00444] [d + Z —7% (33)_
As shown above in (33), 0 is the angle of the ray. The point in perfect
focus is given by the lens maker's equation given in on (34) as follows:
7 — E (34).
Equation (34) may be rearranged to derive Equation (35) as follows:
1 fz
_ _
d—L_l—z—f (35).
f z
Inserting d from Equation (35) into Equation (33) to show the striking
point results in Equation (36) as follows:
z-fZ 62f z+fz2-f2z-fz22 fz
“”4501 +Z_ azopm.
z-f f f(z-f)
All rays g this point strike the focal plane at the optical axis. As
shown in on (37), the situation when the image sensor is shifted by a
distance 5 from the focus is described as follows:
1zffl51_w,fz
[00452]
-f f f(z—f)
zwwz_flgg
f(z-f) m—f)
43759 (37).
Equation (37) shows that by properly positioning the lens of the image
sensor with respect to the focal plane, we can change the depth of field.
Additionally, the spot size depends upon the magnitude of the angle 0. This angle
depends linearly on the aperture of the vision system created by the image sensor.
Additionally or alternatively, in accordance with some embodiments of the
present disclosure, an image sensor may be implemented by ing for various
parameters, including: the distance to the focus as it s tness,
alignment, and sensitivity of the vision system to the environment; the field of view
of the system; and the lens-focal plane separation as it affects the tolerances on
alignment of the system and the sensitivity of the system to the environment.
Embodiments of the flow meter with or without valves connected o
Referring to the drawings, Figs. 43 and 44 show a flow meter 58 coupled
to a drip chamber 59. As described infra, the flow meter 58 may optionally include
a free flow detector component 12 (see Fig. 1) in accordance with an embodiment
of the present disclosure. Additionally, alternatively, or optionally, the flow meter 58
may include a flow rate estimator component 13 (see Fig. 1) in ance with
some embodiments of the present disclosure. Fig. 43 shows the flow meter 58 with
a shut door 62, and Fig. 44 shows the flow meter 58 with an open door 62. The
flow meter 58 may be the flow meter 7 of Fig. 1 with a valve 6 or with no valve. The
flow meter 58 includes a start button 60 and a stop button 61. Additionally or
optionally, the flow meter 58 may include a backup valve to stop fluid from flowing
therethrough or may signal another valve to stop the fluid from flowing in response
to error ions.
The flow meter 58 optionally includes image sensors 63 and 64 that can
te fluid flow and/or detect free flow conditions. Although the flow meter 58
includes two image sensors (e.g., 63 and 64), only one of the image s 63
and 64 may be used in some embodiments. The image sensors 63 and 64 can
image a drop while being formed within the drip chamber 59 and estimate its size.
The size of the drop may be used to estimate fluid flow through the drip chamber
59. For example, in some embodiments of the present disclosure, the image
sensors 63 and 64 use an edge detection algorithm to estimate the outline of the
size of a drop formed within the drip chamber 59; a processor therein (see
sor 15 of Fig. 1, sor 75 of Fig. 5, or processor 90 of Figs. 6 or 8) may
assume the outline is m from every angle of the drop and can estimate the
drops size from the outline. In the exemplary ment shown in Figs. 43 and
44, the two image sensors 63 and 64 may average together the two outlines to
estimate the drops size. For example, the algorithm may average the measured
outlines of the two image sensor 63 and 64 to determine the size of the drop. The
image sensors 63 and 64 may use a reference background pattern to facilitate the
ition of the size of the drop as described herein.
In another embodiment of the present disclosure, the image sensors 63
and 64 image the fluid to determine if a free flow condition exists. The image
sensors 63 and 64 may use a background pattern to determine if the fluid is freely
flowing (i.e., drops are not forming and the fluid streams through the drip chamber
59). As previously ned, although the flow meter 58 includes two image
sensors (e.g., 63 and 64), only one of the image sensors 64 and 64 may be used in
some embodiments to determine if a free flow condition exists and/or to estimate
the flow of fluid through the drip chamber.
onally or alternatively, in some embodiments of the present
disclosure, another image sensor 65 monitors the fluid tube 66 to detect the
presence of one or more bubbles within the fluid tube. In alternative embodiments,
other bubble detectors may be used in place of the image sensor 65. In yet
additional embodiments, no bubble detection is used in the flow meter 58.
Referring now to the drawings, Fig. 45 shows a flow meter 218 coupled
to a drip chamber 219 in accordance with an embodiment of the t disclosure.
The drip chamber 219 is secured to the flow meter 218 via couplers 410. A
backlight 220 shines light through the drip chamber toward the image sensor 221
(shown in outlined form).
The flow meter 218 may electronically transmit a flow rate to a monitoring
client 8 (see Fig. 1). Additionally or atively, in some optional ments,
the flow meter 218 may include a y that displays a flow rate (e.g., a touch
screen, LED display, and the like). The flow meter 218 may be coupled to a pole
223 via clamps 222.
] In some embodiments, the flow meter 218 may be coupled to an actuator
which is d to a valve (not shown in Fig. 45) to form a closed-loop system
(e.g., control component 14 of Fig. 1, such as a PID, bang-bang, neural network, or
fuzzy logic control system) to regulate the flow of fluid through the drip chamber
219.
The flow meter 218 may use any flow algorithm bed herein and
may include any imaging system described herein. Additionally or alternatively, the
flow meter 218 may include a free flow detector component (e.g., the free flow
detector ent 12 of Fig. 1).
Fig. 46 shows a flow meter 224 and a pinch valve 225 coupled to the
body 226 of the flow meter 224 to control the flow of fluid to a patient in accordance
with an embodiment of the present disclosure. The flow meter 224 includes an
image sensor 227 and a backlight 228.
The image sensor 227 images a drip chamber 229 and can receive
illumination from the backlight 228. The flow meter 224 includes a support member
230 coupled to a coupler 231 that couples the drip r 229 to the flow meter
224.
The flow meter 224 may implement any flow rate tor described
herein (e.g., the flow rate estimator component 13 of Fig. 1) and/or a free flow
detector disclosed herein (e.g., the free flow detector component 12 of Fig. 1). The
flow meter 224 may use the pinch valve 225 in a close-loop fashion to control the
flow of fluid to a patient (e.g., using a control component 14 as shown in Fig. 1).
[00468] The pinch valve 225, as is more easily seen in Fig. 47, is coupled to a
shaft 233 which is d to an actuator 234. The actuator 234 may be a solenoid
or any actuator that can move the pinch valve 225 toward a tube 335.
] Fig. 48 shows a flow meter 336 and a pinch valve 225 in accordance with
an embodiment of the present disclosure. The flow meter includes two image
sensors 337 and 338. The flow meter 336 may use the pinch valve 225 in a
closed-loop ck configuration. The flow meter 336 may implement a volume
estimation algorithm described herein using both image sensors 337 and 338 to
te the flow of fluid through the drip chamber 229. For example, the flow
meter 336 may average the two volumes together for use in the feedback loop.
[00470] Fig. 49 shows a flow meter 339 and a valve 340 coupled to an actuator
341 to control the flow of fluid into a patient in accordance with an embodiment of
the present disclosure. The flow meter 339 of Fig. 49 is similar to the flow meter
224 of Fig. 46; r, the flow meter 339 of Fig. 49 includes a valve 340 that has
curved, elongated support members 342 and 343 (see Figs. 50A-50B).
[00471] The flow meter 339 es an image sensor 227 and a backlight 228.
The image sensor 227 images a drip chamber 229 and can receive illumination
from the ght 228. The flow meter 339 includes a support member 230
coupled to a coupler 231 that couples the drip chamber 229 to the flow meter 339.
The flow meter 339 can implement any flow rate estimator described
herein (e.g., the flow rate estimator ent 13 of Fig. 1) and/or a free flow
detector disclosed herein (e.g., the free flow detector component 12 of Fig. 1). The
flow meter 339 may use the valve 340 in a close-loop fashion to control the flow of
fluid into a patient (e.g., using the control component 14 of Fig. 1).
The flow meter 339 may actuate the actuator 341 to actuate the valve
340, which thereby regulates the fluid flowing through the IV tube 335 in a feedback
(i.e., closed-loop) configuration using any control algorithm.
Referring now to Figs. 50A-SOB, which shows close-up views of the valve
340 of Fig. 49 in accordance with an embodiment of the present disclosure. The
valve 340 includes an inner curved, ted t member 343 and an outer
curved, elongated support member 342. The tube 335 is oned between the
support s 342 and 343.
The inner support member 343 includes a barrel nut 344. The outer
support member 342 is coupled to the barrel nut 344 via hooks 345. In some
embodiments, the barrel nut 344 is not coupled to the valve 340 and the inner
support member 342 includes a hole for the threaded rod or screw 347 to slide
through. The outer support member 342 also has hooks 348 to secure it to a frame
349 of the or 341. The actuator 341 includes a shaft 346 coupled to a
screw 347. As the actuator 341 s the shaft 346, the screw 347 can rotate to
push the barrel nut 334 toward the actuator 341. That is, the hooks 345 and the
barrel nut 334 moves toward the hooks 348 and the frame 349 because the inner
and outer support members 342 and 343 are flexible.
As the support s 342 and 343 are compressed, the tube 335
becomes ssed because it is positioned n the support members 342
and 343. Compression of the tube 335 restricts the flow of fluid through the tube
335. The valve 340 compresses a length of the tube 335 that is substantially
greater than the diameter of the tube 335.
Figs. 51A-51 D show several views of a flow meter 350 with a monitoring
client 358, a valve 352, a drip chamber 357, an IV bag 411, and a fluid tube 412 in
accordance with an embodiment of the present disclosure. The flow meter 350
includes a receiving portion 351 to receive the valve 352. The valve 352 es
two curved, elongated support members 353 and 354.
The flow meter 350 includes an image sensor 355 and a backlight 356
that can monitor drops formed within the drip chamber 357. The flow meter 350
may use the image sensor 355 to implement a flow rate estimator algorithm
described herein (e.g., the flow rate estimator component 13 of Fig. 1) and/or to
implement a free flow detector disclosed herein (e.g., the free flow detector
component 12 of Fig. 1).
The flow meter 350 es a base 359 that can form a dock to receive
the monitoring client 358. The monitoring client 358 may be a smart phone, or
other electronic computing device (e.g., an Android-based device, an lphone, a
tablet, a PDA, and the like).
The monitoring client 358 may n software therein to implement a
free flow detector, a flow rate tor, a control component, an exposure
component, etc. (e.g., the free flow or component 12, the flow rate estimator
component 13, the control ent 14, the exposure component 29 of Fig. 1)
and may contain one or more transceivers (e.g., the transceiver 9). Additionally or
alternatively, a base 359 of the flow meter 350 may implement these items.
For example, the flow meter 350 may ent a free flow detector, a
flow rate estimator, a control component, an exposure component, etc. using
internal software, hardware, electronics, and the like. The flow meter 350 may
implement a closed-loop feedback system to regulate the fluid flowing to a patient
by varying the fluid flowing through the valve 352.
As is easily seen in Fig. 51B, the valve 352 includes an inner support
member 354 and an outer support member 353. The inner support member 354 is
coupled to a barrel nut 360 and to a barrel 361. In some embodiments, the barrel
nut 360 is not coupled to the inner support member 354 and the inner support
member 354 includes a hole for the ed shaft 362 to slide through.
A threaded shaft 362 (e.g., a screw) spins freely within a bearing located
within the barrel 361 and engages a threaded nut within the barrel nut 360 to push
or pull the barrel nut 360 relative to the barrel 361 by rotation of the knob 363 (e.g.,
the actuator is a lead screw having a knob to actuate the lead screw.). The knob
363 may be manually rotated.
Additionally or alternatively, the valve 352 may be snapped into the
receiving portion 351 which es a rotating member 364 that engages the knob
363 within the receiving portion 351 (see Fig. 51C). The rotating member 364
s the rotating knob 363 to actuate the valve 352. The rotating member 364
may be d to an electric motor which rotates the ng member 364. The
electric motor (not explicitly shown) may be controlled by the flow meter 350 in a
closed-loop configuration to achieve a target flow rate of fluid flowing into a patient.
Figs. 52A-52D show several views of another flow meter 365 with a valve
352, a drip chamber 357, and a fluid tube trench 413 having a receiving portion 351
to receive a valve 352 in accordance with an embodiment of the present disclosure.
The flow meter 365 of Figs. 52A-52D is similar to the flow meter 350 of Figs. 51A-
51D; however, the base 359 holds the monitoring client 358 in an “upright” position.
Additionally, the receiving portion 351 is on an opposite side of the base 359 from
the monitoring client 358 (see Figs. 52B and 52C).
Fig. 52D shows a up view of the valve 352 engaging the receiving
portion 351. The knob 363 engages a rotating member that is al to the base
359 (not shown in Fig. 52D) that is d to a motor (also not shown in Fig. 52D).
Fig. 53A shows another view of the valve 352 of Figs. 51A-51 D and 52A-
52D, and Figs. 53B-53C show two exploded views of the valve of Fig. 53A in
accordance with an embodiment of the present disclosure.
As shown in Figs. 53A-53C, the valve 352 includes an inner support
member 354 and outer support member 353. A tube may be inserted through
holes 366 and 367 to position the tube between the t members 354 and 353.
[00489] The knob 363 may be turned to turn the screw 362. Rotation of the
screw 362 causes the barrel nut 360 to move toward the partial barrel 363 to
compress a tube positioned between the support members 353 and 354. The
partial barrel 363 includes two sides, r, there is a space to hold the end 600
(e.g., the cap) of the screw 362 securely within the space (e.g., a complementary
space). Fig. 54 shows the valve 352 in manual use and coupled to a tube 368.
Fig. 55 shows a valve 369 that includes two flexible members 370 and
371 in accordance with an embodiment of the present disclosure. The flexible
members 370 and 371 may be two flexible . The flexible member 371 may
include holes 373 and 374 for a tube 372 to be positioned between the flexible
members 370 and 371.
The flexible members 370 and 371 are d together via two
connector members 377 and 378. The connector members 377 and 378 are
d to coupling members 376 and 375, respectively.
Actuation of the valve 369 may be by a linear actuator that pulls the
coupling s 377, 378 toward each other or away from each other. The linear
actuator (not explicitly shown) may be a screw-type actuator, a piston or, or
other actuator. In some embodiments, one of the coupling members 375 and 376
may be d to a stationary support while the actuator is coupled to the other
one of the coupling s 375 and 376 and another stationary support for
pulling the coupling members 375 and 376 together or apart.
Figs. 56A-56C show l views of a valve 380 having two curved,
elongated support members 381 and 382 with one of the elongated t
members 381 having a plurality of ridges 387 adapted to engage a tube oned
between the support members 381 and 382, in accordance with an embodiment of
the present disclosure.
The valve 380 has both support members 381 and 382 coupled to a
coupling member 383 at a first end and a second coupling member 384 at r
end. That is, the coupling member 384 surrounds a screw 385 and the coupling
member 383 includes internal threads for pulling the coupling member 383 toward
or away from a knob 386 when the screw 385 is rotated with rotation of the knob
386. Fig. 56B shows the valve 380 when actuated to close fluid flowing through a
tube coupled n the support members 381 and 382. Fig. 56C shows the
support member 381 having two holes 388 and 389 to receive a tube. Also note
that the support members 381 and 382 hold a tube off center from an axis of the
screw 385, which is easily seen in Fig. 56C. Holding the tube off-center from the
screw’s 385 axis facilitates free movement of the tube.
Figs. 57A-57C show several views of a valve 390 having a ratchet 394
that engages a connecting member 393 of the valve 390 in accordance with an
embodiment of the present disclosure and Figs. 57D-57E show two exploded views
of the valve 390 of Figs. 57A-57C. The ratchet 394 engages the connecting
member 393 by interacting with a gear rack 397 disposed n. A finger 602
(see Figs. 57D and 57E) interacts with a gear rack 397 to provide the ratcheting
action. That is, the finger 602 may hold the gear rack 397 against an engaging
finger on a side opposite of the ing finger 602. The valve 390 includes a
support member 391 having an end coupled to the ratchet 394 and another end
pivotally d to a hinge 395. The valve 390 also includes a support member
392 having hooks 398 that can couple to the body of the ratchet 394.
[00496] As shown in Fig. 57C, a tube 396 can be positioned between the support
members 391 and 392, the hooks 398 can then be ed to the body of the
ratchet 394, and the connecting member 393 can be inserted into the ratchet 394
(as shown in Fig. 57B). As shown in Fig. 57C, the tube 396 is positioned against
the support member 391 via openings 399 and 400.
The ratchet 394 engages the gear rack 397 such that the ratchet 394 can
be manually moved toward the hinge 395 for course fluid flow adjustments.
Thereafter, a knob (not shown) may be coupled to the ratchet 394 to make fine
adjustments to the distance between the t 394 and the hinge 395.
Additionally or alternatively, the ratchet 394 may include a release button (not
shown) to release the ratchet from the connecting member 393.
] Figs. 58A-58D show several views of a valve 401 having two ted
support members 403 and 404, a connecting member 405, and a screw-type
actuator 407 in ance with another ment of the present disclosure.
[00499] The support members 403 and 404 may be ently molded together
at their ends with the ends of the connecting member 405. A tube 402 may be
positioned between the support members 403 and 404.
As the knob 408 is turned, the screw-type actuator 407 expands or
contracts because of engagement with a threaded rod 406. Fig. 58A shows the
valve in an open position while Fig. 58B shows the valve in a closed position. Note
that the tube 402 is ed along a substantial length of the tube 402. Figs.
58C-58D show the valve 401 in the open position and the closed position,
respectively, from a perspective view.
Figs. C show several views of a body 501 of a valve 500 (see Fig.
59H for the assembled valve 500) in accordance with an embodiment of the
present disclosure. The body 501 includes a first curved, elongated support
member 502 and a second curved, elongated support member 503. The first
support member 502 includes raised holes 504, 505 to hold a tube between the
support members 502 and 503.
[00502] The body 501 also includes a first connector 506 that is coupled to the
support members 503, 504 at an end, and a second connector 507 that is coupled
to the other ends of the support s 503, 504.
The first connector 506 is coupled to an end of the support members 503,
504 and to a first end 508 of a connecting member 509. The second connector 507
includes a hole 510 for positioning the second end 511 of the connector member
509 therethrough (as is easily seen in Fig. 59B).
When a tube is positioned between the support members 502, 503,
movement of the second connector 507 toward the first connector 506 compresses
the tube disposed between the support members 502, 503. As the second
connector 507 moves towards the first connector, the hole 510 of the second
connector 507 allows the second end 511 of the connector member 509 to freely
slide therein.
Figs. 59D-59G show several views of a knob 512 for use with the body
501 shown in Figs. 59A-59C in accordance with an embodiment of the present
disclosure. The knob 512 includes a ratchet 513 d by four fingers 514. Each
of the fingers 514 includes a threaded surface 515 to engage a threaded
connecting member 509. The fingers 514 are arched toward a hole 516 at the
center of the knob 512. The knob 512 also es fingers 517 that engage the
second connector 507 (see Fig. 59H). In some embodiments, the body 501
includes a recess 510 to e the fingers 517 on the second connector 508.
Fig. 59H shows an assembly valve 500 that includes the body 501 shown
in Figs. 59A-59C coupled to the knob 512 of Figs. 59D-59G in accordance with an
embodiment of the present disclosure. The knob 512 is slid onto the threads of the
connecting member 509. The fingers 514 engage the threads of the connecting
member 509 and ratchet onto the connecting member 509. That is, the knob 512 is
freely moveable towards the first end 508 of the connecting member 509 along the
threads of the connecting member 509, but cannot be moved away from the first
end 508 of the connecting member 509 without rotating the knob 512. That is, the
knob 512 may be place onto the connecting member 509 to provide a coarse
ment of the valve 500 by coarsely moving the tors 507, 508 toward
each other to close the valve 500. Because the threaded surfaces 515 of the four
fingers 514 engage the threads of the connecting member 509, rotation of the knob
512 either reduces or increases fluid flow within a tube. Each of the s 514
includes a threaded surface 515 to engage the threads of the connecting member
509 such that rotation of the knob 512 moves the second connector 507 toward or
away from the first connector 506 to thereby control the flow of fluid of a tube
oned between the support members 502, 503.
Fig. 60 shows a valve 520 having a guiding sion 521 in accordance
with an embodiment of the t disclosure. The valve 520 is similar to the valve
500 of Fig. 59H, but includes the guiding protrusion 521 and a knob 522 having first
and second collars 523, 524. The knob 522 also includes internal threads (not
shown) to engage threads 525 of a connecting rod 526. In some embodiments, the
al threads may be ratcheting and in other embodiments, the internal threads
may be fixed without providing a ting action.
Fig. 61 shows a motor 536 and valve-securing structure 537 for coupling
to the valve 520 of Fig. 60 in accordance with an embodiment of the present
disclosure. The valve-securing structure 537 includes securing fingers 528, 529,
530, 531 each having a curved portion 533 for snapping onto collars 523, 524 of a
knob 522 (see Fig. 62) into respective collar-guiding portions 534.
Referring now to Figs. 60, 61, and 62 once the s 523, 524 are
sufficiently secured, the knob 522 is free to rotate. That is, the collar 523 may be
secured between the securing s 528 and 530 within their respective collar-
guiding portion 534 allowing the knob 522 to rotate. Likewise, the collar 524 may
be secured n the securing fingers 529 and 531 within their respective collar-
guiding portion 534 allowing the knob 522 to rotate.
When the valve 520 is secured to the valve-securing structure 537,
rotation of the wheel 537 (caused by the motor 536) rotates the knob 522 of the
valve 520. As the valve 520 flexes, the protrusion 521 freely moves within the
protrusion guide 535 or adjacent to the sion guide 535. Fig. 62 shows the
valve of Fig. 60 secured to the motor 536 via the valve-securing structure 537.
Fig. 63 shows another motor 538 and valve-securing ure 539 for
coupling to the valve of Fig. 60 in accordance with an embodiment of the present
disclosure. The valve-securing structure 539 es a protrusion guide 540
adjacent to the motor 538. The motor 538 is coupled to the wheel 541 to engage
the knob 522 (see Fig. 60).
Fig. 64A shows a valve 542 having a slidable collar 545 and l
compressing fingers 544 for regulating fluid flow through a fluid line 543 in
accordance with an embodiment of the present disclosure. The base 546 is
connected to all of the fingers 544. As the slidable collar 545 is moved over the
compressing s 544, the compressing fingers 544 compress the tube 543 to
impede fluid flow therewithin. Fig. 64B shows a cross-sectional view of the valve of
Fig. 64A.
Fig. 64A shows a valve 542 having a slidable collar 545 and l
fingers 544 for regulating fluid flow through a fluid line 543 in accordance with an
embodiment of the present disclosure. The fingers 544 are d to a base 546
such that the base 546 and fingers 544 surround the tube 543. The collar 545 is
slidable away from the base 546 such that the fingers 544 compress the tube 543
which thereby reduces an internal volume of the tube 543. The reduction of the
internal volume of the tube 543 reduces the fluid flow h the tube. An actuator
(not shown) may be coupled to the collar 545 to control the position of the collar
545 (e.g., a linear actuator may be coupled to the collar 545 and to the base 546).
Fig. 64B shows a cross-sectional view of the valve 542 of Fig. 64A. Note that the
fingers 544 may be shaped away from the tube near an opposite end of the base
Fig. 65 shows a valve 547 having two curved surfaces 549 and 550 for
positioning a fluid tube 548 therebetween to regulate fluid flow through the fluid
tube 548 in accordance with an embodiment of the present disclosure. As the
surface are compressed together, the tube 548 is compressed therebetween. The
two curved surfaces 549 and 550 may be compressed together using an or.
The tube 548 may be wrapped several times around the surface 549.
Figs. 66A-66G show l views of a valve 551 having a knob 552 to
move a connecting member 553 which is locked into position after movement of the
knob 552 in accordance with an ment of the present disclosure.
The valve 551 includes an inner curved, elongated t member 554
and an outer curved, elongated support member 556. A knob 552 is pivotally
coupled to the outer support member 556 via a pin 578. A connecting member 553
engages teeth 576 of the knob 552.
The connecting member 553 may be inserted into a hole of an end 555
of the t member 556 such that rotation of the knob 552 frictionally locks an
engaging finger 700 (see Fig. 66D) into the gear rack 558 of the connecting
member 553. The engaging finger 700 may engage the teeth 576 to lock the knob
552 to thereby t rotation of the knob 552 unless ient torque overcomes
the locking action of the engaging finger 700. A retaining finger 577 is oned
on the other side of the hole 571 presses the connecting member 552 against the
teeth 576 of the knob 552.
The inner support member 554 can pivot out away from the outer support
member 556 such that a tube can be loaded via raised portions 559 and 560 (see
Fig. 66C) . The inner support member 554 pivots away from the outer support
member 556 via digbones 561, 562, 701, and 702 as shown in Fig. 66C.
Thereafter, the inner support member 554 pivots back towards the t member
556 as shown in Fig. 66D. The connecting member 553 is then inserted into an
end 555 of the outer support member 556 (a close up of the insertion is shown in
Fig. 66E) that includes the engaging finger 700 that locks onto the teeth 576 of the
knob 552 which temporarily lizes the connecting member 553 (see fig. 66G).
The other end 581 of the ting member 553 is locked into a hole 582 of an
end 557 of the support member 556. The connecting member 553 may be pivotally
connected to the end 557. The knob 552 includes teeth 576 to move the
connecting member 553 in or out of the end 555. r, when the knob 552 is
not moved, the engaging finger 700 locks the movement of the knob 552 unless a
ermined amount of torque clicks the finger 700 to the next tooth of the teeth
576 of the inner portion of the knob 552.
As previously mentioned, the support member 554 can swing away from
the outer support member 556 as is shown in Fig. 66C, which is facilitated by the
dog bone linkers 561, 562, 701, and 702. The dog bone linker 561 es a pivot
hole 572 that couples to a pivot 563, and a pivot hole 573 that couples to a pivot
565. The dog bone linker 562 includes a pivot hole 575 that couples to a pivot 566
and a pivot hole 574 that coupled to a pivot 566. The dog bone linker 701 couples
to pivots 567 and 570, and the dog bone linker 702 couples to pivots 568 and 569
so that the end of the support member 556 also swings away from the inner support
member 554.
[00520] Fig. 67 shows a graphic 408 that illustrates actuation vs. flow rates for a
valve in accordance with an embodiment of the present disclosure. The c
408 shows the operation of a valve having elongated support members, such as,
for example, the valve 340 of Figs. 49 and 50A-50B, the valve 352 of Figs. ,
the valve 369 of Fig. 55, the valve 380 of Figs. 56A-56C, the valve 380 of Figs.
57A-57E, the valve 401 of Figs. 58A-58D, the valve 500 of Fig. 59H, the valve 520
of Figs. 60-60, the valve 542 of Figs. B, the valve 547 of Fig. 65, and/or the
valve 551 of Figs. 66A-66G . The x-axis of the graphic 408 shows the
displacement between the ends of the support members of the valve, and the y-
axis shows the flow rate (e.g., caused by gravity and/or a pressure source). The
response of the valve is a nonlinear function, such as an S—curve, a sigmoid curve,
a Gompertz curve, or a generalized logistic function. These functions may be
adjusted to match the valve and/or the valve may be adjusted to match one of the
curves or functions.
Fig. 68A shows a flow meter 703 that uses binary optics 705 in
accordance with an embodiment of the present disclosure. The flow meter 703
includes a camera 355 that captures one or more images to estimate a flow rate of
fluid through a drip chamber 357 using any sufficient method, e.g., the methods
disclosed herein. The flow meter 703 includes a laser 704 that directs a laser beam
onto a binary optic assembly 705. The binary optics assembly 705 thereafter
cts and reforms the laser beam through the drip chamber 357 and onto the
image sensor 355 such that the image sensor 355 see pattern, e.g., the array of
lines 85 shown in Fig. 8 which may form stripes as shown in the background
pattern 89 of Fig. 10. The binary optics assembly 705 may form the s by
using a plurality of ovals.
The image sensor 355 may include a filter to filter out all ncies
except for the frequency of the laser 704. For example, the image sensor 355 may
include an optical band-pass filter that has a center frequency equal to (or about
equal to) the optical frequency (or center ncy of the optical frequency) of the
laser 704.
The monitoring client 358 may be ically coupled to the laser 801 to
te the laser 801. For e, the monitoring client 358 may turn on the
laser 801 only when predetermined pixels are being exposed and may turn off the
laser 801 when other pixels besides the predetermined pixels are being exposed.
The flow meter 703 optionally es a first electrode 800 and a second
electrode 801. The monitoring client 358 may be electrically coupled to the first and
second electrodes 800, 801 to measure a capacitance defined therebetween. ln
ing conditions, the capacitance changes because the relative permittivity is
different for air and water. The monitoring client 358 may monitor the changes that
s from a streaming condition with the drip chamber 357 by monitoring the
capacitance between the first and second electrodes 800, 801 and ate
increases and/or decreases of the capacitance beyond a old as
corresponding to either a streaming condition and/or a non-streaming condition.
For example, if the capacitance between the first and second electrodes 800, 801
is higher than a threshold, a processer within the monitoring client 358 may
determine that the drip chamber 357 is undergoing a streaming condition.
In an alternative embodiment, the first and second electrodes 800, 801
are loop antennas. The monitoring client 358 uses a transceiver to monitor the
magnetic coupling between the loop antennas 800, 801. For example, the
transceiver may it a coded message from one loop a of the antennas
800, 801, to another one of the loop antennas 800, 801 and then determine if the
coded message was successfully received. If so, then a received signal strength
indication (“RSSI”) ement may be made from the transceiver. The RSSI
may be used to monitor the magnetic ng between the antennas 800, 801. If
the magnetic coupling is above a threshold, then the monitoring client 358 may
determine that a streaming condition exists within the drip r 357. In some
embodiments a change of ic coupling or a change of capacitive ng
may be determined to be an indication that a streaming condition has occurred.
The flow meter 703 may also include a safety valve 706. Figs. 69A-69F
show several views of the safety valve 706 that may be used with a flow meter,
such as the flow meter 703 of Fig. 68, in accordance with an embodiment of the
present disclosure.
[00527] Figs. 69A-69B show exploded views of the safety valve 706. The safety
valve 706 includes a solenoid 707, an interface structure 708, a tube housing 709,
a spring 720, a faceplate 712, a first axle 713, a second axle 714, a first occluding
arm 710, and a second occluding arm 711. The faceplate 712 includes a hole 715
and the tube housing 708 also includes a hole 819. The holes 715, 819 allow the
axle 713 to slide within the holes 715,819.
As shown in Fig. 69C, a tube 820 may be placed within the tube housing
709. Placing the tube 820 places the tube 820 next to the first and second
occluding arms 710, 711, which are easily seen in Fig. 69D. A spring 720 keeps
the first and second ing arms 710, 711 retraced when in the retracted state
(as shown in Fig. 69D), but stores energy such that a predetermined amount
movement of the first and second occluding arms 710, 711 towards the tube 810
cause the spring to discharge its stored mechanical energy to cause the first and
second occluding arms 710, 711 to extend out and e the tube 820. The
spring 720 may be a compression spring 720 may pull 713 and 714 towards each
other. The first and second occluding arms 710, 711 are pivotally connected
together. As is easily seen in Fig. 69E, a shaft 718 of a solenoid 707 can actuate
through a hole 719 in the tube to push on the spring 720 which causes the spring
720 to release its energy and occlude the tube 820 (see Fig. 69F for the case when
WO 96722
the where the first and second occluding arms 710, 711 are in the occluding
position).
Fig. 70 shows a flow chart diagram rating a method 728 of
estimating drop growth and/or flow within a drip chamber in accordance with an
embodiment of the present disclosure. The method 728 includes acts 729-735.
Figs. 71A-71 B show images take by a flow meter with a template overlaid therein to
illustrate the method of Fig. 70.
Act 729 captures an image of a drip chamber. The image capture may
be the image 721 of Fig. 71A. Act 730 positions a template within the capture
image to a first position. For example, as shown in Fig. 71A, a template 727 may
be positioned within a predetermined position. Act 731 averages all of the pixels
within the template 727. Act 732 moves the template to a second position. For
example, the te 727 in Fig. 71A may move the te in the Y direction
(e.g., down as seen in Fig. 71A).
] In act 733, the pixels within the template are used to ine a second
average. In act 734, if a difference between the second average and the first
e is greater than a predetermined threshold value, determine that the
template is located at an edge of a drop. For example, referring to Fig. 71A, the
template may be slowly lowered down in the Y direction, until the template 727
transitions from the edge of a drop to a n of the image that doesn’t contain the
drop, in which case the average value of the pixels will transition abruptly to a dark
average to a lighter average. When this transition occurs, the Y position of the
template 727 is considered to be at the edge of the drop (e.g., Y1 of Fig. 71A). ln
act 735, the second position of the drop is correlated with a volume of the drop.
For example, the Y1 value may be associated with a volume of a drop in a lookup
table. In some embodiments of the t disclosure, multiple movements of the
template 727 are needed to until the edge of the drop is detected. For e,
the template 727 may be moved in the y-direction one pixel at a time (or several
pixels at a time) and several template 727 movements may be needed such that
the edge of the drop is detected. By monitoring the edge of the drop, the growth of
the drop may be controlled by the flow meter to achieve a target flow rate (e.g., the
rate of the transition between Y1 of Fig. 71A to Y2 of Fig. 71 B may be controlled by
a PID control loop within a flow meter). Fig. 718 shows a location, Y2, that
corresponds to a growth in the drop relative to the location, Y1, of Fig. 71A.
Fig. 72 shows a modulateable backlight assembly 740 in accordance with
an embodiment of the present disclosure. The assembly 740 may be the backlight
18 of Fig. 1 or may be used as a backlight for any sufficient flow meter disclosed
herein. The assembly 740 includes a first circuit board 738, a second circuit board
739, a first backlight diffuser 736, and a second backlight diffuser 737.
The first circuit board 738 includes embedded light s 822 that
extend along the interface between the first backlight diffuser 736 and the first
circuit board 738. The embedded light s 822 shine light into the first
backlight diffuser 736 which is directed outwards as indicated by 821. The light 821
may be directed s an image sensor. The first backlight diffuser 736 only
diffuses light with no “pattern” formed when viewed by an image .
] The second circuit board 739 includes ed lights 823 which are
shined into the second backlight diffuser 737. The second backlight diffuser 737
creates a n of stripes that show up in light 821 when viewed by an image
sensor. Therefore, a monitoring client (e.g., the monitoring client 358 of Fig. 51A)
and/or a flow meter (e.g., the flow meter 7 of Fig. 1) can select between a striped
background pattern (by ting the embedded lights 823) and a non-striped
background pattern (by activating the embedded lights 822).
For example, referring now to Figs. 1 and 72, the flow meter 7 may use
the backlight assembly 740 in some specific embodiments; The flow meter 7 may
use a non-striped backlight pattern (by activating the embedded LEDs 822 t
activating the embedded LEDs 823) to monitor the growth of drops and may switch
to a striped ound pattern (by activating the embedded LEDs 823 without
activating the embedded LEDs 822) to detect streaming conditions.
[00536] Figs. 73A-73C show several views of a tube-restoring apparatus 741 in
accordance with an embodiment of the present disclosure. The apparatus 741
includes a drive gear 744 that is coupled to a first restoring gear 742. The first
restoring gear 742 is mechanically coupled to a second restoring gear 743. A tube
may be placed between the first and second restoring gears 742, 743. ns of
the first and second restoring gears 742, 743 define a space 745 in which a tube
may be positioned. Rotation of the first and second restoring gears 742, 743
closes the distance between the space 745 when the tube is positioned between
the first and second restoring gears 742, 743. The transition from a non-restoring
on to a restoring position is shown in Fig. 73B to Fig. 73C. For example, a
tube may be positioned such that an occlude presses against the tube from the
bottom up (as shown in Fig. 73B). If the tube becomes distorted over time, a motor
connected to the driving gear 744 rotates the gears 743 and 744, to press against
the walls of the tube (as shown in Fig. 73C) to restore the tube to an approximate
cross-section by compressing on the wall portions of the tube that are expanded
beyond a center axis of the tube such that the tube is distorted into an oval shape,
for e.
Fig. 74 shows a system for regulating fluid flow 746 using a valve 747
having two flexible strips 753 and 754 (see Fig. 75); And Fig. 75 shows the valve
746 of Fig. 74 in accordance with an embodiment of the present disclosure.
Optionally, a motor may be attached to the valve 746 for control by a flow meter in
one embodiment.
As shown in Fig. 75, the valve 74 includes two flexible strips 753, 754 in
which a tube may be disposed therebetween, a guiding shaft 752, to guidable
members 749, 750, a screw 751, and a knob 748.
When the knob 748 is turned, the screw 751 rotates. on of the
screw 751 pulls the distal guiding member 750 toward the proximal guiding member
749 (because the distal g member 750 includes internal threads and the
screw 751 spins freely within the proximal guiding member 749). The guide 751
guides the movement of the distal guiding member 750. The guide 751 is coupled
to the proximal guiding member 749.
FigA. 76 shows a valve 755 that es a fluid-based bladder 758 in
accordance with an ment of the present disclosure. The valve 755 includes
two clamshells 756, 757, a bladder 758, and a piston 759. The piston 759 may be
any fluid source. The bladder 758 may be placed within a cavity 764 and a tube
may be placed across the bladder 758 and positioned within the hways 760
and 761. Thereafter, the clamshell 757 may be placed over the bladder 758 such
that the cavity 765 is placed over the r 758. The two ells 756, 757
may then be ultrasonically welded together, temporarily compressed er,
and/or sufficiently held together. Thereafter, an actuator (e.g., an actuator
controlled by a flow meter disclosed herein) may be actuated to move fluid in and
out of the bladder 758 via the piston 759.
Fig. 76B shows a sectional view of the assembled valve 755 of Fig.
76A with two elastomeric fillers 1002, 1004 in accordance with an embodiment of
the present disclosure. The elastomeric fillers 1002, 1004 help hold the tube 1000
into position and help restore the tube 1000 when the bladder 758 is deflated.
Fig. 77 shows a system 766 for regulating fluid flow using a valve 769
having two flexible strips 771, 772 actuateable by a linear actuator 822 in
accordance with an embodiment of the present disclosure. Fig. 78 shows the linear
actuator 822 actuating the valve 769 to impeded fluid flow through a tube 775. The
valve 769 is coupled to two couplers 767 and 768. The proximal coupler 768
moves with the linear actuator 822 while the distal r 767 is fixed relative to a
ving end of the linear actuator 822.
[00543] Fig. 79 shows a close-up of the valve 769 of Figs. 77-78. The valve 769
includes two strips 771, 772 (which may be metallic strips) in which the tube 775
may be disposed. The two strips 771, 772 of the valve 769 may be coupled to a
first end ure 773 and a second end structure 774. The first end structure 773
may be coupled to the distal coupler 767 and the second end structure 774 may be
coupled to the proximal coupler proximal r 768 (see Figs. 77-78). A string
770 or membrane may be wrapped around the tube 775 such that, when the strips
771, 772 are straightened out, the string 770 presses against the side walls of the
tube 775 to help round the tube 775. The membrane may be a flexible by not
stretchable material (or minimally stretchable material). Fig. 80 shows a close-up of
the valve as ed in Fig. 78. Note that holes 776 and 778 that the string 770 is
threaded h. The string 770 (which may metallic) is spiraled around the tube
775 such that when the valve 769 opens, the string 770 restores the tube 775.
Fig. 81 shows several images for use to rate a method of estimating
drop growth and/or fluid flow illustrated in Figs. 82A-82B in accordance with an
embodiment of the present disclosure. Fig. 81 shows images 771-777 which are
referred to below regarding Figs. 82A-82B.
Figs. B show a flow chart diagram illustrating a method 803 of
estimating drop growth and/or fluid flow. The method 803 includes acts 804-818.
Act 804 captures a first image (e.g., image 771 of Fig. 81). The first
image may be a grey scale image of the drop changer. The drop chamber may be
uniformly lit with a striped pattern on the bottom of the r (i.e., there is no
back pattern on the top portion of the drop r).
Act 805 creates a first thresholded image using the first image. The first
thresholded image may be the image 774 of Fig. 81. The first thresholded image
may be made by comparing each pixel from the first image to a old value
(e.g., setting a respective pixel of the thresolded to 0 if the respective pixel of the
first image is above the threshold or setting a respective pixel of the thresholded to
1 if the tive pixel of the first image is below the threshold). This act is to
highlight areas where there is water in front of the background.
In some specific embodiments, the threshold level is updated every time
a new image is taken to ensure ermined ratio of 1 to 0 pixels is maintained to
highlight the drop. The ratio may be updated for use by act 805 when used again
or the update may adjust the threshold until a predetermined ratio of 1 to 0 pixels is
made and then use the first thresholded image for the rest of the method 803.
Act 806 determines a set of pixels within the first thresholded image
connected to a predetermined set of pixels within the first thresholded image. The
predetermined set of pixels may be ined by fiducials marked on the drip
chamber or an opening in which drops are formed. The predetermined set of pixels
may be a predetermined set of x, y values that correspond to pixels. Act 806 may
use a connected component image analysis algorithm.
Act 807 filters all remaining pixels of the first thresholded image that are
not with the set of pixels. The filter operates on a by-pixel basis within the
time domain to generate a first filtered image. The first filtered image is an estimate
of a non-active (e.g., a result from features not of st in the image) n of
the first thresholded image (image 774 of Fig. 81). The filter may be any filter, e.g.,
any filter described herein.
Act 808 removes pixels determined to not be part of a drop from the first
thresholded image using the first filtered image to generate a second image (e.g.,
image 775 of Fig. 81). A pixel within the second image will be set to 1 if a
respective pixel in the first thresholded image is 1 and a respective pixel in the first
filtered image is less than 0.5, ise, the pixel will be set to 0.
Act 809 determines a second set of pixels within the second image
connected to a predetermined set of pixels within the second image to generate a
third image (e.g., the image 776 of Fig. 81). The third image identifies the second
set of pixels within the second image. Act 809 finds the set of “lit” pixels in the
second image connected to the predetermined set of pixels (e.g., pixels
representing the opening in which drops are formed).
Act 810 determines a first length of the drop by counting the number of
rows containing pixels corresponding to the second set of pixels within the third
image. That is, the drop length is determined to be equal to the last “lit” row in the
set of pixels found in Act 809. The first length corresponds to a first estimated drop
size.
Act 811 updates a background image using the first image. A low-pass
filter may be used to update each pixel’s value in the ound image. An te
impulse response filter may be used to update the ound image using the first
image. A pixel is only updated in the ound image for rows below the first
length plus a predetermined safety zone. A pixel in the background image is
updated by low pass filtering the value from the corresponding pixel in the first
image.
] Act 812 creates a second thresholded image (e.g., image 772 of Fig. 81)
by ing first image with the background image. That is, the first image has
the background image subtracted from it, and on a pixel-by-pixel basis, the
absolute value of each pixel is set to 1 if it is above a second old value and
set to a 0 if it is below the second threshold value to generate the second
thresholded image.
Act 813 sums the rows of second thresholded to create a plurality of row
sums (see image 773 of Fig. 81). Each row sum corresponds to a row of the
second olded image.
Act 814 starts at a row position of the second thresholded image having a
first sum of the plurality of sums that corresponds to the first length. The row
position in incremented in act 815. Act 816 determines whether the present row
position correspond to a corresponding row sum that is below a threshold, e.g.,
zero. If no, then act 815 is preformed again until the present row position
corresponds to a corresponding row sum that is zero and then the method 803
proceeds to act 817.
Act 817 determines a second length is equal to the present row position.
The second length corresponding to a second estimated drop size. Act 818
averages the first and second lengths to ine a average length. The average
length corresponding to a third estimated drop size. By using the first and second
lengths to determine an average length, the effects of condensation on the inner
walls of the drip chamber are mitigated. That is, the purpose of creating two
2012/071142
estimates of drop length is to sate for how each length is affected by the
presence of condensation. The first length tends to underestimate drop length if a
drop of condensation intersects the growing drop from the spigot. The second
length tends to overestimates the drop length if the drop of condensation intersects
the growing drop from the spigot. Their average provides a better estimate when
condensation is present. In the absence of condensation, the estimates are almost
equal. In other embodiments, only either the first or second length is used to
estimate the drop size.
Fig. 83 shows a flow chart m of a method 900 for reducing noise
from condensation in accordance with an embodiment of the present disclosure.
Method 900 includes acts 902-910.
Act 902 es an image of a drip chamber. Act 904 performs a canny,
edge-detection operation on the image to generate a first processed image. Act
906 performs an AND-operation on a pixel on a first side of an axis of the first
processed image with a corresponding mirror pixel on the second side of the axis of
the first processed image. That is, Act 902 defines an axis in the first s
image, and performs an AND on each pixel on one side with a pixel on the other
side, such that the pixel on the other side is symmetrical with the pixel on first side.
For e, a 40 (X-axis) by 40 (Y-axis) image may have an axis defined between
pixel columns 19 and 20. The top, left pixel would be pixel (1,1) A pixel at location
(1, 5) would be AND-ed by with a pixel at (40,5). The resulting pixel would be used
for both locations (1, 5) and (40,5) to te the second processed image.
That is, after act 906 is performed, act 908 determines whether all of the
pixels have been processed. Act 908 s act 906 until all pixels have been
processed. Act 910 provides a second processed image that is the results of all of
the AND operations.
] Various alternatives and modifications can be devised by those skilled in
the art without departing from the disclosure. Accordingly, the t disclosure is
intended to embrace all such atives, modifications and variances.
Additionally, while several embodiments of the present disclosure have been
shown in the drawings and/or discussed herein, it is not intended that the
disclosure be limited thereto, as it is intended that the disclosure be as broad in
scope as the art will allow and that the specification be read likewise. Therefore,
the above description should not be construed as limiting, but merely as
exemplifications of particular ments. And, those skilled in the art will
envision other modifications within the scope and spirit of the claims appended
hereto. Other elements, steps, methods and techniques that are insubstantially
different from those described above and/or in the appended claims are also
intended to be within the scope of the disclosure.
The ments shown in the drawings are presented only to
demonstrate certain examples of the disclosure. And, the drawings described are
only illustrative and are non-limiting. In the drawings, for illustrative purposes, the
size of some of the elements may be exaggerated and not drawn to a ular
scale. Additionally, elements shown within the drawings that have the same
numbers may be identical elements or may be r elements, depending on the
context.
Where the term "comprising" is used in the present description and
claims, it does not exclude other elements or steps. Where an indefinite or definite
e is used when referring to a singular noun, e.g., "a, an," or "the,” this
includes a plural of that noun unless something otherwise is specifically stated.
Hence, the term "comprising" should not be reted as being restricted to the
items listed thereafter; it does not exclude other elements or steps, and so the
scope of the expression "a device comprising items A and B" should not be limited
to devices consisting only of components A and B. This expression signifies that,
with respect to the present disclosure, the only relevant components of the device
are A and B.
Furthermore, the terms "first," "second," "third," and the like, whether
used in the description or in the claims, are provided for distinguishing n
similar elements and not arily for describing a sequential or chronological
order. It is to be understood that the terms so used are interchangeable under
appropriate circumstances (unless clearly disclosed otherwise) and that the
ments of the disclosure described herein are capable of operation in other
sequences and/or arrangements than are bed or illustrated herein.
Claims (31)
1. An apparatus, comprising: a coupler d to couple to a drip chamber; a support member operatively d to the coupler; an image sensor having a field of view and operatively coupled to the support member, wherein the image sensor is positioned to view the drip chamber within the field of view; a valve configured to couple to a fluid tube in fluid communication with the drip chamber, wherein the valve is configured to regulate flow through the fluid tube to thereby regulate the fluid flow through the drip chamber; at least one processor operatively coupled to the image sensor to receive image data rom, wherein the at least one processor is configured to: capture a plurality of images of the drip chamber using the image sensor; estimate a volume growth rate of the drop within the drip chamber using the plurality of images; receive a set point corresponding to a fluid flow rate through the fluid tube; adjust a control system in accordance with the estimated volume growth rate of the drop to achieve the set point; and output a control signal from the control system to an actuator of the valve to control actuation of the valve in accordance with the adjusted control system.
2. The tus according to claim 1, further comprising a non-transitory processor-readable memory having an operative set of processor executable instructions stored n, the non-transitory processor-readable memory is in operative communication with at least one processor such that the operative set of processor executable ctions controls the operation of the at least one processor.
3. The apparatus according to claim 1, further comprising a ansitory processor-readable memory readable by the at least one processor, wherein the non-transitory sor-readable memory includes an ive set of processor executable instructions stored thereon configured to cause the at least one processor, when executed, to: capture the plurality of images of the drip chamber using the image sensor; estimate the volume growth rate of the drop within the drip chamber using the plurality of images; e the set point corresponding to the fluid flow rate through the fluid tube; adjust the control system in ance with the estimated volume growth rate of the drop to achieve the set point; and output the control signal from the control system to an actuator of the valve to control actuation of the valve in accordance with the ed control system.
4. The apparatus ing to claim 1, wherein the apparatus further comprises the control system and n the control system is at least one of a proportional–integral–derivative control system, a proportional–integral l system, a proportional-derivative control system, a proportional control system, an integral control system, a neural net control system, a fuzzy logic control system, and a bang-bang control system.
5. The apparatus according to claim 1, wherein the apparatus further comprises the control system and wherein the control system correlates the estimated volume growth rate of the drop with the fluid flow through the fluid tube.
6. The apparatus ing to claim 1, wherein the valve comprises: the or; a curved, elongated support member cally deformable and having first and second ends; and an opposing support member configured to position the fluid tube against the curved, elongated support member between the first and second ends, wherein deformation of the curved, elongated support member by movement of the first and second ends toward each other reduces an internal volume of the fluid tube, wherein the actuator is configured to move the first and second ends toward each other.
7. The apparatus according to claim 1, wherein the valve comprises: the actuator; a first elongated support member ng a length; and a second elongated support member defining a length, wherein the length of the second elongated t member is disposed in spaced on with the length of the first elongated support member to cooperate with the first elongated support member to compress the fluid tube, wherein the actuator is in mechanical engagement with at least one of the first and second elongated support members to actuate the first and second elongated support members toward each other to thereby compress the fluid tube disposed therebetween to regulate flow of fluid within the fluid tube, wherein actuation of the actuator actuates the first and second elongated support members to regulate fluid flow within the tube in accordance with an approximate sigmoid curve, Gompertz curve, or lized logistic function.
8. The tus according to claim 1, wherein the valve ses: the actuator; a first support member that forms at least one of an arc, a plurality of arcs, a curve, a plurality of , an arcuate shape, a plurality of arcuate shapes, an S- shape, a C-shape, a convex shape, a plurality of convex shapes, a concave shape, and a plurality of convex shapes; and a second support member disposed in spaced relation with the first t member to cooperate with the first support member to compress the fluid tube along a length of the fluid tube at least substantially greater than the diameter of the fluid tube, n the actuator is in mechanical engagement with at least one of the first and second support members to actuate the first and second support members toward each other to thereby ss the fluid tube disposed therebetween to regulate flow of fluid within the fluid tube, wherein actuation of the actuator actuates the first and second support members to regulate fluid flow within the fluid tube in ance with an approximate nonlinear function.
9. The apparatus according to claim 1, wherein the valve comprises: a curved, elongated support member elastically deformable and having first and second ends; and an opposing support member configured to define a conduit with the curved, elongated support , wherein the conduit is defined between the , elongated support member and the opposing member, wherein the valve is configured to couple to the fluid tube so that the fluid tube is disposed within the conduit and ation of the curved, elongated support member by nt of the first and second ends toward each other reduces an internal volume of the fluid tube within the conduit.
10. The apparatus according to claim 1, wherein the valve is an inverse- Bourdon-tube valve coupled to the fluid tube to regulate the fluid flowing through the fluid path of the fluid tube.
11. The apparatus according to claim 1, wherein the valve comprises: the actuator; a first le member; and a second flexible member operatively coupled to the first flexible member, n: the valve is configured to couple to the fluid tube so that the fluid tube is disposed between the first and second flexible members, the first and second flexible s are configured to flex to thereby regulate flow of fluid passing through the fluid tube, and the actuator is coupled to at least a first end of the first flexible member and a second end of the first flexible member.
12. The apparatus ing to claim 1, wherein the valve comprises: the actuator; a first C-shaped member defining inner and outer surfaces; and a second C-shaped member defining inner and outer surfaces; wherein: at least one of the outer surface of the first C-shaped member and the inner surface of the second C-shaped member is configured to receive the fluid tube, the inner surface of the second C-shaped member is disposed in spaced relation to the outer surface of the first C-shaped member, the actuator is coupled to the first and second C-shaped s to bend the first and second C-shaped members to ss the fluid tube.
13. The tus according to claim 1, wherein the valve comprises: the actuator; a first flexible sheet; and a second flexible sheet operatively coupled to the first flexible sheet; wherein: the first and second flexible sheets are configured to receive the fluid tube therebetween, the first and second flexible sheets are configured to flex to thereby regulate flow of fluid passing through the fluid tube, the actuator is coupled to the first and second flexible sheets to te flow of fluid passing through the fluid tube.
14. The apparatus according to claim 1, wherein the valve comprises: the actuator; a first curve-shaped member defining inner and outer surfaces; and a second curve-shaped member defining inner and outer surfaces, wherein: the inner surface of the second curve-shaped member is disposed in spaced relation to the outer surface of the first curveshaped member with the fluid tube disposed between the first and second curved-shaped members, and the actuator is coupled to the first and second shaped members to bend the first and second shaped members to thereby regulate the flow of fluid within the fluid tube.
15. The tus according to claim 1, wherein the valve comprises: the actuator; a first curve-shaped member defining inner and outer surfaces, the first curve-shaped member having first and second receiving members at opposite ends of the first curve-shaped member; and a second curve-shaped member defining inner and outer surfaces, the second curve-shaped member having first and second ers at te ends of the second curve-shaped member, wherein: the first ing member of the first curve-shaped member is configured to engage the first fastener of the second curve-shaped member, the second receiving member of the first shaped member is configured to engage the second fastener of the second curve-shaped member, and the actuator is coupled to the first and second curve-shaped members to bend the first and second curve-shaped members to regulate the flow of fluid of the fluid tube disposed therebetween.
16. The apparatus according to claim 1, wherein the valve comprises: the or; a first curved, elongated support member elastically deformable and having first and second ends; and a second curved, elongated support member elastically deformable and having first and second ends, n the second curved, elongated support member is configured to position the fluid tube against the first curved, elongated t, wherein ation of the first and second curved, elongated support members by movement of the first and second ends of the first curved, elongated support member toward each other reduces an internal volume of the fluid tube; a first connector coupled to the first end of the first curved, elongated support member and coupled to the first end of the second curved, elongated support a second connector coupled to the second end of the first curved, elongated support member and coupled to the second end of the second curved, ted support member, wherein the second connector defines a hole; a connecting member having an end coupled to the first connector and another end configured for insertion into the hole of the second connector, wherein the connecting member defines a threaded rod at least along a portion thereof; and a knob having a ratchet ured to ratchet onto the connector member when moved from the r end of the connecting member toward the end of the connector member, wherein the knob is further configured to engage the threaded rod of the connecting member, wherein the actuator is coupled to the knob to rotate the knob.
17. The apparatus according to claim 1, wherein the valve comprises: the actuator; a base ng a hole configured to receive the fluid tube; a plurality of fingers each having an end coupled to a base; and a ring ured to slide from the base and along the plurality of fingers, wherein movement of the ring from the base compresses the s against the fluid tube, wherein the ring is configured to frictionally lock against the plurality of fingers, wherein the actuator is coupled to the ring to slide the ring.
18. The apparatus according to claim 1, wherein the valve comprises: the actuator; a conically-shaped member having a e for wrapping the fluid tube therearound; and a complementing member configured to engage the conically-shaped member for compressing the tube, wherein the actuator is configured to compress the conically-shaped member t the complementing member to thereby compress the fluid tube.
19. The apparatus according to claim 1, wherein the apparatus further comprises the control system and wherein the control system is implemented in hardware.
20. The apparatus according to claim 1, wherein the apparatus r comprises the control system and wherein the control system is implemented by at least one ional amplifier.
21. The tus according to claim 1, further comprising a non-transitory processor-readable , wherein: the control system is implemented by an operative set of processor able instructions configured for execution by the at least one processor, the operative set of processor executable instructions is stored on the non-transitory processor-readable memory, and the non-transitory processor-readable memory is in operative communication with the at least one processor to ively communicate the operative set of processor executable instructions to the at least one processor for execution by the at least one processor.
22. The apparatus ing to claim 1, wherein the set point is compared to the volume growth rate of the drop to adjust the l system; wherein the set point is compared to the volume growth rate of the drop to determine an error signal; wherein the error signal is the difference between the set point and the volume growth rate of the drop; wherein the error signal is passed through a signal processing apparatus to generate the output signal; and wherein the signal sing apparatus implements a proportional-integral-derivative ller with at least one non-zero gain parameter.
23. The apparatus according to claim 1, wherein the at least one processor determines an existence of a free flow condition using the plurality of images.
24. The apparatus according to claim 23, further comprising a background n positioned within the field of view of the image sensor wherein the drip chamber is between the image sensor and the background pattern.
25. The apparatus according to claim 24, wherein the at least one processor estimates at least one parameter using the plurality of images by analyzing a distortion of the background pattern caused by the liquid within the field of view as viewed by the image sensor.
26. The tus according to claim 25, wherein the ound pattern is an array of lines having at least one angle relative to an opening of the drip chamber when viewed from the image sensor within the field of view using the plurality of images.
27. The apparatus according to claim 26, wherein the at least one processor determines a free flow condition exists when the liquid causes the array of lines to change angles by distortion caused by the liquid when in the free flow condition as viewed within the field of view from the image sensor.
28. The apparatus according to claim 1, wherein the at least one processor is configured to: select a region of interest of the image sensor; determine if a pixel of the image sensor is within the region of interest; activate a light of a backlight if the pixel of the image sensor is within the region of interest; and expose the pixel of the image sensor.
29. The apparatus according to claim 1, further comprising a light coupled to the support member and adapted to illuminate the image sensor to expose the image sensor such that the field of view of the image sensor at least partially images at least a n of the drip chamber, wherein the at least one processor is configured capture an image including an image of a drip chamber using the image sensor having a field of view including the drip chamber; subtract the image from a background image to thereby generate a difference image; convert each pixel of the difference image to a true value if an absolute value of a respective pixel is beyond a predetermined old or to a false value if the absolute value of the respective pixel is less than the ermined threshold; sum each row of the converted difference image to generate a plurality of summation values, n each summation value of the plurality of summation values corresponds to a respective row of the converted difference image; and examine the ity of summation values.
30. The apparatus according to claim 1, n the at least one processor is ured to: capture an image of the drip chamber; on a template within the captured image to a first position; average the pixels within the template to determine a first average; move the template to a second position; average the pixels within the template to determine a second average; determine that the template is located at an edge of a drop if a difference between the second average and the first average is greater than a predetermined threshold value; and correlate the second position with a volume of the drop.
31. An apparatus according to claim 1, substantially as herein bed or exemplified with reference to the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NZ715098A NZ715098B2 (en) | 2011-12-21 | 2012-12-21 | Apparatus for controlling fluid flow |
Applications Claiming Priority (15)
Application Number | Priority Date | Filing Date | Title |
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US201161578658P | 2011-12-21 | 2011-12-21 | |
US201161578649P | 2011-12-21 | 2011-12-21 | |
US201161578674P | 2011-12-21 | 2011-12-21 | |
US61/578,649 | 2011-12-21 | ||
US61/578,658 | 2011-12-21 | ||
US13/333,574 | 2011-12-21 | ||
US13/333,574 US10453157B2 (en) | 2010-01-22 | 2011-12-21 | System, method, and apparatus for electronic patient care |
US61/578,674 | 2011-12-21 | ||
PCT/US2011/066588 WO2013095459A1 (en) | 2011-12-21 | 2011-12-21 | System, method, and apparatus for electronic patient care |
USPCT/US11/66588 | 2011-12-21 | ||
US201261651322P | 2012-05-24 | 2012-05-24 | |
US61/651,322 | 2012-05-24 | ||
US201261679117P | 2012-08-03 | 2012-08-03 | |
US61/679,117 | 2012-08-03 | ||
PCT/US2012/071142 WO2013096722A2 (en) | 2011-12-21 | 2012-12-21 | System, method, and apparatus for monitoring, regulating, or controlling fluid flow |
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NZ626382A NZ626382A (en) | 2016-02-26 |
NZ626382B2 true NZ626382B2 (en) | 2016-05-27 |
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