NZ623804B2 - Stretch sensor device - Google Patents
Stretch sensor device Download PDFInfo
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- NZ623804B2 NZ623804B2 NZ623804A NZ62380412A NZ623804B2 NZ 623804 B2 NZ623804 B2 NZ 623804B2 NZ 623804 A NZ623804 A NZ 623804A NZ 62380412 A NZ62380412 A NZ 62380412A NZ 623804 B2 NZ623804 B2 NZ 623804B2
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- New Zealand
- Prior art keywords
- stretch
- data
- sensor
- body part
- motion
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- 125000004122 cyclic group Chemical group 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 8
- 210000002683 Foot Anatomy 0.000 claims description 36
- 210000000474 Heel Anatomy 0.000 claims description 10
- 210000003371 Toes Anatomy 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 6
- 238000004590 computer program Methods 0.000 claims description 5
- 210000000056 organs Anatomy 0.000 claims 1
- 238000004450 types of analysis Methods 0.000 abstract 4
- 238000011068 load Methods 0.000 description 11
- 230000000875 corresponding Effects 0.000 description 5
- 206010022114 Injury Diseases 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 230000003902 lesions Effects 0.000 description 2
- 210000000450 navicular bone Anatomy 0.000 description 2
- 230000003287 optical Effects 0.000 description 2
- 210000003491 Skin Anatomy 0.000 description 1
- 210000000707 Wrist Anatomy 0.000 description 1
- 230000001070 adhesive Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 238000010219 correlation analysis Methods 0.000 description 1
- 230000003247 decreasing Effects 0.000 description 1
- 230000001419 dependent Effects 0.000 description 1
- 230000033001 locomotion Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000069 prophylaxis Effects 0.000 description 1
- 230000001360 synchronised Effects 0.000 description 1
- 230000001702 transmitter Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/1036—Measuring load distribution, e.g. podologic studies
- A61B5/1038—Measuring plantar pressure during gait
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
- A61B5/1116—Determining posture transitions
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
- A61B5/112—Gait analysis
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
- A61B5/1126—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb using a particular sensing technique
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/6802—Sensor mounted on worn items
- A61B5/6804—Garments; Clothes
- A61B5/6807—Footwear
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/6813—Specially adapted to be attached to a specific body part
- A61B5/6829—Foot or ankle
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/683—Means for maintaining contact with the body
- A61B5/6832—Means for maintaining contact with the body using adhesives
- A61B5/6833—Adhesive patches
Abstract
Disclosed is a sensor device configured to process stretch data for determining a stretch value of a body part. The sensor device comprises a stretch sensor directly connected to the body part for obtaining stretch data (100). The stretch sensor is a capacitive or resistive sensor, which changes its capacitance or resistance as a function of elongation. The sensor device is configured to process stretch data from the stretch sensor for determining a stretch value of the body part. The sensor device comprises a processor configured for analysing the stretch data while the body part is in motion; and analysing the stretch data to identify portions (104) of the cyclic stretch data (100) which correspond to motions of the body part. The portions (104) of the stretch data are identified so that the portions (104) contain first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part. The sensor device analyses the cyclic stretch data (100) to identify first and second stretch values (101, 102) by determining minimum and maximum sensor values (121,122). The sensor device further analyses the cyclic stretch data (100) to identify the portions (104) ensuring that the portions (104) contain portions of an entire period (106) of a cyclic harmonic signal containing first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part and to distinguish values related to other motion phases (143). The sensor device is also configured for analysing the identified portions (104) of stretch data (100) to determine first and second sensor values (121, 122) of the respective first and second stretch data points (101,102); and determining stretch values (103) by determining the differences between the first and second sensor values (121, 122). capacitance or resistance as a function of elongation. The sensor device is configured to process stretch data from the stretch sensor for determining a stretch value of the body part. The sensor device comprises a processor configured for analysing the stretch data while the body part is in motion; and analysing the stretch data to identify portions (104) of the cyclic stretch data (100) which correspond to motions of the body part. The portions (104) of the stretch data are identified so that the portions (104) contain first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part. The sensor device analyses the cyclic stretch data (100) to identify first and second stretch values (101, 102) by determining minimum and maximum sensor values (121,122). The sensor device further analyses the cyclic stretch data (100) to identify the portions (104) ensuring that the portions (104) contain portions of an entire period (106) of a cyclic harmonic signal containing first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part and to distinguish values related to other motion phases (143). The sensor device is also configured for analysing the identified portions (104) of stretch data (100) to determine first and second sensor values (121, 122) of the respective first and second stretch data points (101,102); and determining stretch values (103) by determining the differences between the first and second sensor values (121, 122).
Description
STRETCH SENSOR DEVICE
FIELD OF THE INVENTION
The invention relates to a method for determining movement of a human or
animal body part on basis of measured stretch data.
BACKGROUND OF THE INVENTION
A non-optimal movement pattern of the body or parts of the body is a major
cause of pain and lesions or injuries in the locomotion system. Movement analysis
is crucial for prophylaxis, diagnosing and treatment of such lesions, and in sports
an optimal movement pattern is essential for optimal and injury free performance.
Until now movement analysis has primarily been performed by monitoring
movement of points on the body during motion, e.g. by use of advanced video
technology where retro reflective optical markers on the body are tracked during
motion with one or multiple video cameras. However, such video-based methods
for analysing body motion and body loads are impractical since they normally
require use of a treadmill and large dedicated rooms.
Accordingly, there is a need to enable monitoring of body motion without
restricting the motion to be carried out in a particular environment, room or with
use of a treadmill.
US 2010324457 discloses a system that records position data for portions of a
body as a function of time. The position data can be collected from one or more
sensors secured to the body either individually or using a patch. The sensors, in
some embodiments, can include stretch sensors that produce a change in
electrical resistance as the stretch sensors are stretched as a result of body
movement. A data logger can be used to record the data. Various other elements
such as a feedback mechanism or a manual pain indicator can also be included.
The inventor of the present invention has appreciated that improved methods
analysing body motion for determining body load is of benefit, and has in
consequence devised the present invention.
SUMMARY OF THE INVENTION
It would be advantageous to achieve improved method for determining body loads
during motion. It would also be desirable to enable determination of body loads
without restricting the motion to be performed in a particular environment. In
general, the invention preferably seeks to mitigate, alleviate or eliminate one or
more of the above mentioned disadvantages singly or in any combination. In
particular, it may be seen as an object of the present invention to provide a
method that solves the above mentioned problems, or other problems, of the
prior art.
To better address one or more of these concerns, in a first aspect of the invention
a sensor device is presented that is configured to process stretch data from a
stretch sensor for determining a stretch value of a body part, where the sensor
device comprises a processor configured to
- analyse the stretch data to identify a portion of the stretch data which
corresponds to a motion of the body part, where the portion of the stretch data is
identified so that the portion contains first and second stretch data points
associated with respective first and second motion-phases of the body part,
- analyse the identified portion of stretch data to determine first and second
sensor values of the respective first and second stretch data points,
- determine a stretch value from the first and second sensor values.
It is understood that the first and second stretch data points are separated in time
and located within a cyclic period of the stretch data.
Since the sensor device is configured to determine a stretch value from specific
stretch data samples of the measured stretch data - where the specific stretch
data samples are associated with specific motion phases – it is ascertained that
the stretch value is indicative of a particular stretch directly related, e.g. to the
navicular drop. The motion phases may be predefined phases such as particular
motion phases of a foot.
The determination of stretch values may be used for determining movement of
the body part, i.e. high stretch values which may indicate a high harmful
overload. The sensor device may be used by professionals for determining load
values of patients or the sensor device may be used by non-professionals e.g. by
athletes for determining the load of a body part during training. For example, the
sensor device may be used by runners for avoiding overloading of the foot by
determining when the stretch values of the foot are becoming too high. Thereby,
the athlete is able to maximize training efforts without the risk of overload
injuries.
Herein the word movement is used to define the stretch or movement of a body
part, i.e. a stretch or movement between two points on a body part, such as
between the tuberosity of the navicular bone and the center of the medial
malleolus. The movement may be used for assessing the load of the particular
body part. The word motion is used to define e.g. walking, running or other
motions of a body part.
The sensor device is particularly advantageous since it enables determination of
stretch values by use of a single sensor. That is, no other sensors than a stretch
sensor is required since the sensor device enables determination of stretch values
in a way so that the stretch values are synchronized with the body motion.
In an embodiment of the invention the body part is a foot, where the portion of
the stretch data corresponds to a walking or running motion, where the first
motion-phase of the foot is the heel strike, and where the second motion-phase of
the foot is the mid stance, i.e. the phase where both the toe and the heel are in
contact with the ground.
In an embodiment the first data point is determined by determining a minimum
value within at least a fraction of the identified portion of the stretch data and the
second data point is determined by determining a maximum value within at least
a fraction of the determined portion of the stretch data.
In an embodiment the second data point is determined by determining a
maximum value within at least a fraction of the portion of the stretch data and the
first data point is determined by determining a minimum value located in time
before the second data point.
The stretch data may have a profile so that the maximum value always
corresponds to a specific motion phase (e.g. both heel and toes are in contact
with ground) and so that the minimum value located in the determined portion of
the stretch data and before the maximum value always corresponds to another
specific motions phase (heel impact).
In an embodiment of the processor comprised by the sensor device is further
configured for determination of a period of time between the first and second
stretch data points. This period may advantageously be used as a second measure
(in addition to the first measure of stretch data) for determining the movement of
the body part. E.g. a period of time between the first and second stretch data
points which increases may indicate a decreased stability (corresponds to a
softness) of the body part and, thereby, an increased risk of an overload injury.
In an embodiment the period of time between the first and second stretch data
points is compared with a period of time of the cyclic walking motion for
determination of the stability of the body part.
In an embodiment the sensor device further comprises a processor or filtering
electronics for low pass filtering the stretch data.
A second aspect of the invention relates to a sensor system comprising
- a sensor device according to the first aspect,
- a stretch sensor configured to be directly or indirectly connected to a body part
for determining a stretch value of a body part.
The stretch sensor may be a capacitive or resistive sensor which changes its
capacitance or resistance as a function of elongation. Accordingly, stretch data
can be determined from the stretch sensor by monitoring changes in the sensor’s
electrical characteristics.
A third aspect of the invention relates to a method for determining a stretch value
of a body part, the method comprises,
- obtaining stretch data from a stretch sensor connected to the body part,
- analysing the stretch data to identify a portion of the stretch data which
corresponds to a motion of the body part, where the portion of the stretch data is
identified so that the portion contains first and second stretch data points
associated with respective first and second motion-phases of the body part,
- analysing the identified portion of stretch data to determine first and second
sensor values of the respective first and second stretch data points,
- determining a stretch value from the first and second sensor values.
A fourth aspect of the invention relates to a computer program containing
computer program instructions for enabling processor to carrying out of a method
according to the third aspect.
In summary the invention relates to a method for determining stretch values and
loading of body parts, e.g. a foot, by analysing stretch data from a stretch sensor.
By analysing the stretch sensor it is possible to determine stretch samples which
are associated with particular motion phases. Thereby the stretch values
determined from the stretch samples have a particular physical meaning since
they are associated with particular motion phases.
In general the various aspects of the invention may be combined and coupled in
any way possible within the scope of the invention. These and other aspects,
features and/or advantages of the invention will be apparent from and elucidated
with reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will be described, by way of example only, with
reference to the drawings, in which
Fig. 1 shows a curve 100 of measured stretch data,
Fig. 2 shows a stretch sensor 201 attached to a foot for determining a stretch of
the foot such as navicular drop,
Fig. 3 shows sensor device 301 configured to process stretch data from a stretch
sensor 302, and
Fig. 4 shows a second example of a curve 400 of measured stretch data.
DETAILED DESCRIPTION OF EMBODIMENTS
Fig. 1 shows a stretch data curve 100 of measured stretch data from a stretch
sensor. The stretch data curve 100 is analyzed by a sensor device for determining
a stretch value 103 of e.g. a foot.
Fig. 2 shows a stretch sensor 201 attached to a foot for measuring a stretch of the
foot. In Fig. 2 the sensor is located close to the points 202 (the tuberosity of the
navicular bone), and 203 (the center of the medial malleolus) for measuring the
navicular drop 210 of the point 202. The heel part 205 and the toe part 204 of the
foot are also indicated. A stretch of the foot such as the navicular drop 210 is
indicative for the load of the foot.
From the stretch data curve 100 in Fig. 1 it is possible to determine stretch values
of the foot. However, in order to relate the measured stretch to e.g. load of the
foot the measured stretch has to be associated with a particular motion of the
foot. By identifying particular motion phases of the foot the stretch values
measured when the foot is in these phases can be used to quantify the load of the
foot. An example of determining a stretch for a particular motion of the foot is
given below.
The motion of the foot is shown in Fig. 1 with three motion phases 111-113. The
first motion phase 111 is the heel strike where the heel 205 contacts the ground,
the second motion phase 112 is the mid stance, i.e. the phase where both the toe
204 and the heel 205 contacts the ground and the third phase 113 is the toe-off,
i.e. the phase where only the toe 204 contacts the ground before set-off.
In the second phase 112 the stretch between the first and second points 202,203
are maximal, and in the first phase 111 the stretch between the first and second
points 202,203 are minimal. Accordingly, the difference between the stretch
values in the first and second phases 111, 112 gives a measure of the loading of
the foot during walking or running.
In Fig. 1 the measured stretch value or sensor value 121 at the first stretch data
point 101 corresponding to the first motion phase 111, is a global minimal value
during the entire data curve 100 or at least during a motion period 106. Similarly,
the sensor value 122 at the second stretch data point 102 corresponding to the
second motion phase 112, is a global maximal value during the entire data curve
100 or at least during a motion period 106. Accordingly, in an embodiment the
first and second stretch data points 101, 102 could simply be determined by
determining the minimal and maximal sensor values 121,122 in a given time
interval of the data curve 100. However, since it may be important that the
determined stretch data points are associated with particular predetermined
motion phases, this simple approach could lead to an incorrect stretch value 103 if
e.g. the minimum value of some reason is not located at the first motion phase
111, but at some other motion phase 143.
As an example, Fig. 4 shows a stretch data curve 400 of measured stretch data
from a stretch sensor. In Fig. 4 the sensor value of the first stretch data point 401
corresponding to the first motion phase 111, is not a minimal value within a
motion period 406. Only the sensor value at the second stretch data point 402
corresponding to the second motion phase 112 is a maximal value during a
motion period. The minimum value is located at some other motion phase 443.
Accordingly, Fig. 4 shows an example where the first stretch point 401 cannot be
determined by the simple approach where the first stretch point 401 is assumed
to be a minimum value during a motion period.
To avoid incorrectly determined stretch values, the stretch data 100 is
advantageously analyzed to identify a portion 104 of the stretch data which
corresponds to some motion cycle (e.g. the cycle comprising motion phases 111-
113) of e.g. the foot, where data is analyzed in a way so that this portion 104
contains the first and second stretch data points 101,102 associated with the
respective first and second motion-phases 111,112 of the foot.
The portion 104 may be identical to an entire period 106 or the portion may be a
fraction of a complete period 106. Here a period is understood as a period of a
harmonic signal, for example the cyclic data curve 100.
The portion 104 of the stretch data containing the first and second data points
101,102 may be identified from a correlation analysis of the stretch data to
identify e.g. the high frequency dip of the curve 100 near the start point 141 of a
period and the low frequency dip near the end point 142 so as to identify the
illustrated fraction 104 of an entire period 106 of the cyclic motion pattern.
Accordingly, the portion 104 of the stretch data 100 may be determined by
determining a start point 141 and an end point 142 so that the stretch data
contained between the start point 141 and the end point 142 corresponds to at
least a fraction of one period 106 of a period of the motion.
Having identified the portion 104 of stretch data 100 the first and second sensor
values 121, 122 of the respective first and second stretch data points 101,102 can
be determined, and from the sensor values 121, 122 a resulting stretch value 103
can be determined, e.g. by determining the difference between the first and
second sensor values 121, 122.
Having identified the portion 104 of the stretch data, the first data point 101 may
be determined by determining a minimum value within at least a fraction of the
identified portion, e.g. a first fraction including the start point of the portion 104
and having a given duration equal to a fraction of the duration of the entire
portion 104. Similarly, the second data point 102 may be determined by
determining a maximum value within at least a fraction of the determined portion
104 of the stretch data, e.g. a second fraction starting where first fraction ends
and ending at the end point of the portion 104.
Assuming that the second data point 102 can be uniquely identified from the
maximum value of the stretch data, then according to an embodiment the second
data point 102 can be determined by determining a maximum value within at
least a fraction of the portion 104 of the stretch data 100. Having initially
identified the second data point, the first data point 101 can be determined by
determining a minimum value located in time before the second data point 102
and within the portion 104.
From the above discussion it is clear that a period 106 or a fraction thereof, i.e. a
portion 104, can be identified by analysing the stretch data signal e.g. by
frequency analysis. It is also clear that the first and second data points 101, 102
corresponding to first and second motion phases 111, 112 can be identified by
analysing the data within the identified period 106 or portion 104 thereof, e.g. by
searching for minimal and maximal values, e.g. by use of a peak detector.
In an aspect of the invention a period of time 105 between the first and second
stretch data points 101, 102 is determined e.g. by calculating the difference of the
time stamps of the first and second stretch data points. The period of time 105
gives an indication of the softness of the foot or other body part and, thereby, an
indication of the loading of the foot since the softness tends to increase with
increased loading of the foot. Accordingly, the change of the period of time 105
during monitoring of stretch data 100 may be used for assessing the softness of
the foot. A decrease in the time period corresponds to an increase in softness. The
period of time 105 may be compared with the period of time 106 of the cyclic
motion, or a fraction 104 thereof, to get an absolute measure of the softness of
the body part such as the foot.
The sensor values from the stretch sensor may be noisy and, therefore, a
processor or filtering electronics for low pass filtering the stretch data may be
used.
Fig. 3 shows a sensor system 300 which comprises the sensor device 301 for
analysing stretch data and a stretch sensor 302. The sensor device 301 may
include a processor 303 configured for analysing the stretch data and determining
stretch values 103. The processor need not be part of the sensor device 301.
The sensor system 300 may be configured in various ways. The sensor device 301
may be an electronic device configured to be carried by the user, e.g. on a wrist.
Such a sensor device may receive stretch data wirelessly from the stretch sensor
which may include a transmitter for transmitting data to a receiver of the sensor
device 301. The sensor device 301 may include a display for displaying results of
determined stretch values. The sensor device may be configured so that only part
of the processing of stretch data 100 is carried out by the sensor device 301
whereas other parts of the processing of stretch data may be carried out by other
processing devices, e.g. a computer which is connectable to the sensor device
301. Accordingly, the sensor device 301 may contain a storage for storage of
stretch data or processed stretch data, so that another processor unit may be
connected (wirelessly or wired) to the sensor device. The stretch sensor 302 may
also contain a processor and or a storage for storing measured stretch data 100
so that the sensor device 301 or some other processor may be connected to the
stretch sensor 302 via a transmitter-receiver pair for further processing of the
stored stretch data.
Whereas the determination of stretch values and analysis of stretch values has
been described on basis of a foot and foot motion, the invention is equally
applicable to other body parts and their motion phases. For example, the stretch
sensor may be attached to the shoulder of a person in order to determine stretch
values of shoulder by identifying a portion 104 of the stretch data which
corresponds to at least a fraction of a complete period of cyclic motion of the
shoulder, where the portion of the stretch data is identified so that the portion
contains first and second stretch data points 101, 102 associated with respective
first and second motion-phases of the shoulder, and by analysing the identified
portion of stretch data to determine first and second sensor values 121, 122 so
that a stretch value 103 can be determined. The invention described herein may
be particularly, but not exclusively, applicable to determining stretch values of
body parts where a cyclic motion of the body part can be identified.
The stretch sensor 302 may be connected to a body part by connecting the sensor
directly to the skin (e.g. by use of some adhesive material), or the sensor may be
indirectly attached, e.g. by integrating the sensor with a sock or a shoe.
An aspect of the invention include socks, shoes or bandages wherein the sensor
system or the stretch sensor is integrated for enabling indirect attachment of the
sensor.
While the invention has been illustrated and described in detail in the drawings
and foregoing description, such illustration and description are to be considered
illustrative or exemplary and not restrictive; the invention is not limited to the
disclosed embodiments. Other variations to the disclosed embodiments can be
understood and effected by those skilled in the art in practicing the claimed
invention, from a study of the drawings, the disclosure, and the appended claims.
In the claims, the word "comprising" does not exclude other elements or steps,
and the indefinite article "a" or "an" does not exclude a plurality. A single
processor or other unit may fulfill the functions of several items recited in the
claims. The mere fact that certain measures are recited in mutually different
dependent claims does not indicate that a combination of these measures cannot
be used to advantage. A computer program may be stored/distributed on a
suitable medium, such as an optical storage medium or a solid-state medium
supplied together with or as part of other hardware, but may also be distributed in
other forms, such as via the Internet or other wired or wireless telecommunication
systems. Any reference signs in the claims should not be construed as limiting the
scope.
Claims (9)
- CLAIMS 1 A sensor device (301) configured to process stretch data (100) for determining a stretch value of a body part, where the sensor device comprises a stretch sensor (201, 302) directly connected to the body part for obtaining stretch data (100), where the stretch sensor is a capacitive or resistive sensor, which changes its capacitance or resistance as a function of elongation, - where the sensor device (301) is configured to process stretch data from the stretch sensor (201, 302) for determining a stretch value of the body part, where the sensor device comprises a processor (303) configured for: - analysing the stretch data while the body part is in motion, - analysing the stretch data to identify portions (104) of the cyclic stretch data (100) which correspond to motions of the body part, where the portions of the stretch data are identified so that the portions contain first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part, - analysing the cyclic stretch data (100) to identify first and second stretch values (101, 102) by determining minimum and maximum sensor values (121,122), - further analysing the cyclic stretch data (100) to identify the portions (104) ensuring that the portions (104) contain portions of an entire period (106) of a cyclic harmonic signal containing first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part and to distinguish values related to other motion phases (143, 443), - analysing the identified portions (104) of stretch data (100) to determine first and second sensor values (121, 122) of the respective first and second stretch data points (101,102), and - determining stretch values (103) by determining the differences between the first and second sensor values (121, 122).
- 2. A sensor device according to claim 1, where the body part is a foot, where the portion (104) of the stretch data corresponds to a walking or running motion, where the first motion- phase of the foot is a heel strike (111), and where the second motion-phase of the foot is the phase where both the toe (204) and the heel (205) contacts the ground (112).
- 3. A sensor device according to any of the preceding claims, where a first data point (101) is determined by determining a minimum value within at least a fraction of an identified portion (104) of the stretch data and a second data point (102) is determined by determining a maximum value within at least a fraction of said determined portion (104) of the stretch data.
- 4. A sensor device according to any of the preceding claims, where a second data point (102) is determined by determining a maximum value within at least a fraction of a portion (104) of the stretch data and where a first data point (101) is determined by determining a minimum value located in time before the second data point (102).
- 5. A sensor device according to any of the preceding claims, comprising determination of a period of time (105) between the first and second stretch data points within a portion (104) of the stretch data.
- 6. A sensor device according to claim 5, where the period of time (105) between the first and second stretch data points is compared with a period of time (104) of a cyclic walking motion for determination of a softness of the body organ.
- 7. A sensor device according to any of the preceding claims, where a processor or filtering electronics is used for low pass filtering the stretch data.
- 8. A sensor system comprising - a stretch sensor (201, 302) configured to be directly connected to a body part for determining stretch or movement values of a body part, and - a sensor device (301) configured for - obtaining stretch data (100) from the stretch sensor (201, 302) connected to the body part, where the stretch sensor is a capacitive or resistive sensor, which changes its capacitance or resistance as a function of elongation, where the sensor device (301) is configured to process stretch data from the stretch sensor (201, 302) for determining a stretch value of the body part, where the sensor device comprises a processor (303) configured for: - analysing the stretch data while the body part is in motion, - analysing the stretch data to identify portions (104) of the stretch data which correspond to motions of the body part, where the portions of the stretch data is identified so that the portions contain first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part, - analysing the cyclic stretch data (100) to identify first and second stretch values (101, 102) by determining minimum and maximum sensor values (121,122), - further analysing the cyclic stretch data (100) to identify the portions (104) ensuring that the portions (104) contain portions of an entire period (106) of a cyclic harmonic signal containing first and second stretch data points (101, 102) associated with respective first and second motion-phases of the body part and to distinguish values related to other motion phases (143, 443), - analysing the identified portions (104) of stretch data (100) to determine first and second sensor values (121, 122) of the respective first and second stretch data points (101,102), and - determining stretch values (103) by determining the differences between the first and second sensor values (121, 122).
- 9. A computer program containing computer program instructions for enabling a processor to carrying out steps the processor is configured for according to any of claims 1 - 8.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DKPA201170521 | 2011-09-22 | ||
DKPA201170521 | 2011-09-22 | ||
PCT/DK2012/050341 WO2013041101A1 (en) | 2011-09-22 | 2012-09-11 | Stretch sensor device |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ623804A NZ623804A (en) | 2014-12-24 |
NZ623804B2 true NZ623804B2 (en) | 2015-03-25 |
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