GB2519075A - Apparatus and method for measuring pulse rate - Google Patents
Apparatus and method for measuring pulse rate Download PDFInfo
- Publication number
- GB2519075A GB2519075A GB1317730.8A GB201317730A GB2519075A GB 2519075 A GB2519075 A GB 2519075A GB 201317730 A GB201317730 A GB 201317730A GB 2519075 A GB2519075 A GB 2519075A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sensing unit
- pulse rate
- photo sensing
- output
- microprocessor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 10
- 239000003990 capacitor Substances 0.000 claims description 21
- 210000003462 vein Anatomy 0.000 claims description 20
- 238000004891 communication Methods 0.000 claims description 7
- 238000005259 measurement Methods 0.000 claims description 6
- 238000012935 Averaging Methods 0.000 claims description 5
- 230000003247 decreasing effect Effects 0.000 claims description 5
- 230000000630 rising effect Effects 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 4
- 230000002123 temporal effect Effects 0.000 claims description 4
- 238000009532 heart rate measurement Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 210000000707 wrist Anatomy 0.000 description 3
- 244000309466 calf Species 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 210000003141 lower extremity Anatomy 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 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
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/024—Detecting, measuring or recording pulse rate or heart rate
- A61B5/02416—Detecting, measuring or recording pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/024—Detecting, measuring or recording pulse rate or heart rate
- A61B5/02438—Detecting, measuring or recording pulse rate or heart rate with portable devices, e.g. worn by the patient
-
- 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
- A61B5/6803—Head-worn items, e.g. helmets, masks, headphones or goggles
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7221—Determining signal validity, reliability or quality
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/74—Details of notification to user or communication with user or patient ; user input means
- A61B5/742—Details of notification to user or communication with user or patient ; user input means using visual displays
- A61B5/7445—Display arrangements, e.g. multiple display units
-
- 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
- A61B5/6831—Straps, bands or harnesses
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Medical Informatics (AREA)
- Surgery (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Veterinary Medicine (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Public Health (AREA)
- Molecular Biology (AREA)
- Physics & Mathematics (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Cardiology (AREA)
- Physiology (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Psychiatry (AREA)
- Signal Processing (AREA)
- Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
Abstract
The present invention provides a pulse rate measuring apparatus comprising a microprocessor 1, a light source 2, a photo sensing unit 3, an output means 4 and a casing (5, figure 1). The microprocessor is configured to determine if the photo sensing unit is in contact with the users skin, and if the photo sensing unit is determined as being in contact with the users skin, the microprocessor is configured to adjust light intensity of the light source until the microprocessor successfully recognizes a predetermined number of continuous pulses and thereafter perform pulse rate calculation to obtain an output pulse rate for outputting to the output means. The skin contact can be determined by calculating if the DC component of the voltage waveform from the photo sensing unit is zero or alternatively below a predefined threshold. If this is the case it means no or very weak ambient light is detected by the photo sensing unit and so contact with a users skin is presumed. The light source and photo sensing unit are preferably spaced apart and a light blocker positioned therebetween to prevent light from the light source directly entering the photo sensing unit.
Description
APPARATUS AND METHOD FOR MEASURING PULSE RATE
The present invention relates to a healthcare apparatus and more particularly pertains to an apparatus for measuring pulse rate. The present invention also relates to a method for measuring pulse rate.
Due to increased awareness of body health, many devices are currently available in the market for assessing body condition, analyzing the relevant data and providing an analysis result. Many of these devices are for personal use. For example, such device may take the form of a finger clip for wearing on a user's finger during exercise, and therefore provides continuous monitoring of the user's body condition. The finger clip is provided with a light source for emitting light to the user's finger tip, and a light sensor for sensing the light reflected from the blood through the capillary vessels under the finger tip for detecting the pulse rate. However, the reliability of such devices is easily affected by various factors such as the interference from extraneous light sources.
Besides, such devices are usually designed for use on one specific bodily part (e.g. the temporal regions, upper wrist, etc.), which is sometimes inconvenient for the user.
In view of the aforesaid disadvantages now existing in the prior arts, the present invention provides a method and an apparatus for measuring pulse rate which may be used on different bodily parts and provide a reliable measurement. The present invention attains that by emitting light to veins and capillary blood vessels that are a few millimeters under a user's skin; volumetric changes of the veins and capillary blood vessels during pulsaUons causes changes in the light intensity of the light reflected; by measuring the light reflected and calculating the changes in the light intensity, the present invention provides a measurement of the pulse rate of the user.
To attain this, the pulse rate measuring apparatus of the present invention comprises: a microprocessor; a light source for emitting light to veins and capillary blood vessels under a user's skin which is electrically connected with the microprocessor; a photo sensing unit for detecting light emitted to and reflected from the veins and capillary blood vessels which is electrically connected with the microprocessor; an output means electrically connected with the microprocessor; a casing which accommodates the microprocessor, the light source, the photo sensing unit and the output means; wherein the microprocessor is configured to determine if the photo sensing unit is in contact with the user's skin, and if the photo sensing unit is determined as being in contact with the user's skin, the microprocessor is configured to adjust light intensity of the light source until the microprocessor successfully recognizes a predetermined number of continuous pulses and thereafter perform pulse rate calculation to obtain an output pulse rate for outputting to the output means.
The photo sensing unit outputs electronic signals in form of voltage waveform with a DC component representing ambient light intensity and an AC component representing intensity of the light reflected from the veins and capillary blood vessels.
The microprocessor is configured to determine if the photo sensing unit is in contact with the user's skin by determining if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit is zero or below a predefined threshold; if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit is zero or below a predefined threshold, it means no or very weak ambient light is detected by the photo sensing unit and so the photo sensing unit is determined as being in contact with the user's skin; if the voltage waveform of the DC component of the electronic signals output from the photo sensing unit exceeds the predefined threshold, it means strong ambient light is detected and so the photo sensing unit is determined as not being in contact with the user's skin.
The light source is connected to the microprocessor via a variable resistor; the photo sensing unit is connected to the microprocessor via a voltage amplifier which amplifies and filters the voltage waveform of the electronic signals output from the photo sensing unit for recognition by the microprocessor.
The microprocessor successfully recognizes a pulse by detecting a rising edge, a peak and a decreasing edge of the voltage waveform of the electronic signals output from the photo sensing unit and amplified and filtered by the voltage amplifier.
The microprocessor adjusts light intensity of the light source by adjusting resistance value of the variable resistor.
The microprocessor performs pulse rate calculation to obtain an output pulse rate for outputting to the output means by (i) obtaining a pulse rate for each of a predetermined number of pairs of successive pulses, wherein a pulse rate of each pair of successive pulses is obtained by measuring a time period in seconds between the peak of a first pulse of the pair of successive pulses and the peak of a second pulse of the pair of successive pulses and dividing 60 by the time period; (ii) obtaining the output pulse rate for outputting to the output means by averaging the pulse rates obtained for the predetermined number of pairs of successive pulses; (iii) if necessary, repeat (i) and (ii) for a predetermined number of times to update the output pulse rate for outputting to the output means.
In one embodiment, the voltage amplifier is an operational amplifier which comprises an input, a first sub-operational amplifier, a first capacitor, a first resistor, a low pass filter, an active low pass filter and an output. The input collects the voltage waveform of the electronic signals output from the photo sensing unit and connects to the first sub-operational amplifier. The first sub-operational amplifier serves as a voltage follower which eliminates the unwanted effects due to the change of the impedance of the photo sensing unit. The first capacitor is used to block the DC component of the voltage waveform of the electronic signals which is an unwanted signal for the measurement of the pulse rate. The first capacitor is connected to ground via the first resistor. The first resistor is used to discharge the first capacitor, so that the first capacitor, which is charged during normal operation, will not result in additional DC for the active low pass filter and hence error signal at the output. The low pass filter is formed by a second resistor and a second capacitor, and is used to suppress the unwanted high frequency noise from the photo sensing unit. The active low pass filter is formed by a second sub-operational amplifier, a feedback resistor and a feedback capacitor, and is used to amplify the voltage waveform for the microprocessor and further suppresses the unwanted high frequency noise. The output delivers the voltage waveform from the active low pass filter to the microprocessor.
The light source may comprise one or more than one light sources.
The light source operates at a wavelength between 400nm and 900nm. It has been found that light with a wavelength between 400nm and 900nm can penetrate a few millimeters under a user's skin surface, which contain the skin layers of derma and upper subcuticle rich in veins and capillary blood vessels. The veins and capillary blood vessels undergo volumetric changes corresponding to the pulses, and the amount of light (with a wavelength between 400nm and 900nm) reflected by the veins and capillary blood vessels vary according to their volumetric changes. As a result, by measuring the changes in the light intensity of the light reflected, a measurement of the pulse rate could be obtained.
The light source and the photo sensing unit are positioned spaced apart from each other, preferably by 2mm, with a light blocker positioned therebetween to prevent light from the light source from directly entering the photo sensing unit, thus ensuring light sensed by the photo sensing unit comes from the reflection of the skin, thereby improving accuracy of the pulse rate measurement.
The light blocker is dark in color, soft and elastic, as well as electrically insulative; It could be made of materials such as such as Ethylene-vinyl acetate (EVA) or epoxy resin. The dark color prevents light from the light source from directly entering the photo sensing unit, thus ensuring light sensed by the photo sensing unit comes from the reflection of the skin, thereby improving accuracy of the pulse rate measurement. The soft and elastic texture ensures that the light source and the photo sensing unit are properly isolated from each other, and properly shields the light source and the photo sensing unit from dust and moisture. The electrically insulative character protects the light source and the photo sensing unit from short circuiting.
The photo sensing unit may be in form of a photodiode or a phototransistor.
The output means comprises a wireless communication module which transmits the pulse rate calculated by the microprocessor to an external device.
The external device is a personal computer or a mobile device which operates a mobile software application to analyze, display and store the pulse rate transmitted from the wireless communication module.
The output means comprises an audio output unit which outputs the output pulse rate in an audio manner.
The casing is in form of an eyeglass frame; the output means comprises a micro projection unit which outputs the output pulse rate as an image formed by lights projecting out from the micro projection unit on a display area on the eyeglass frame; the eyeglass frame has two legs, each of which is provided with an elastic protrusion; the light source and the photo sensing unit are positioned on one of the elastic protrusions facing the user's skin; the elastic protrusions serve as a clamp to ensure a close contact between the light source and the photo sensing unit and the user's temporal skin region.
The casing is in form of accessories wearable on a person's different bodily parts, and the accessories may be attached to an adjustable strap which may be worn at different bodily parts including calf, wrist, upper arm, chest, lower limb and so forth.
A motion sensing unit is further provided in the casing for measuring motion of the user, and the output of the motion sensing unit is transmitted to the output means.
The present invention also provides a method for measuring pulse rates which comprises the following steps: (i) emitting light from a light source to veins and capillary blood vessels under a user's skin; (ii) detecting light emitted to and reflected from the veins and capillary blood vessels by a photo sensing unit; (iU) determining if the photo sensing unit is in contact with the user's skin; (iv) adjusting light intensity of the light source until a predetermined number of continuous pulses are successfully recognized if the photo sensing unit is determined to be in contact with the user's skin; (v) performing pulse rate calculation to obtain an output pulse rate.
Step (U) further comprises outputting electronic signals in form of voltage waveform with a DC component representing ambient light intensity and an AC component representing intensity of the light reflected from the veins and capillary blood vessels by the photo sensing unit.
Step (iH) further comprises determining if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit is zero or below a predefined threshold; if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit is zero or below a predefined threshold, it means no or very weak ambient light is detected by the photo sensing unit and so the photo sensing unit is determined as being in contact with the user's skin; if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit exceeds the predefined threshold, it means strong ambient light is detected and so the photo sensing unit is determined as not being in contact with the user's skin.
Recognizing a pulse comprises the steps of detecting a rising edge, a peak and a decreasing edge of the voltage waveform of the electronic signals output from the photo sensing unit and amplified and filtered by a voltage amplifier.
Step (v) further comprises the steps of (i) obtaining a pulse rate for each of a predetermined number of pairs of successive pulses, wherein a pulse rate of each pair of successive pulses is obtained by measuring a time period in seconds between the peak of a first pulse of the pair of successive pulses and the peak of a second pulse of the pair of successive pulses and dividing 60 by the time period; (ii) obtaining the output pulse rate for outputting to the output means by averaging the pulse rates obtained for the predetermined number of pairs of successive pulses; (iii) if necessary, repeat (i) and (ii) for a predetermined number of times to update the output pulse rate.
FIG. 1 is a perspective view of the first embodiment of the present invention.
FIG. 2 is a diagram illustrating the structure of the light source, the photo sensing unit and the light blocker of the first embodiment.
FIG. S is a block diagram of the first embodiment.
FIG. 4 is a circuit diagram of the voltage amplifier of the first embodiment.
FIG. 5 is a graph illustrating the voltage waveform of the electronic signals output from the photo sensing unit of the first embodiment.
FIGs. 6a to 6c are perspective views of the casings of other embodiments.
The present invention will be further described in detail below with reference to a few embodiments and the accompanying drawings. However, the present invention should not be limited by the detailed description herein.
As illustrated in FIGs. 1-5, the pulse rate measuring apparatus of the first embodiment of the present invention comprises a microprocessor 1, a light source 2, a photo sensing unit 3, an output means 4 and a casing 5 which accommodates the microprocessor 1, the light source 2, the photo sensing unit 3 and the output means 4.
The casing 5 in this embodiment is in form of an eyeglass frame. The eyeglass frame has two legs, each of which is provided with an elastic protrusion 51; the light source 2 and the photo sensing unit 3 are positioned on one of the elastic protrusions 51 facing the user's skin; the elastic protrusions 51 serve as a clamp to ensure a close contact between the light source 2 and the photo sensing unit 3 and the user's temporal skin region. The output means 4 is electrically connected with the microprocessor 1, and further comprises a wireless communication module 41, an audio output unit 42 and a micro projection unit 43. The wireless communication module 41 transmits the output pulse rate calculated by the microprocessor 1 to an external device 9 which could be a personal computer or a mobile device which operates a mobile software application to analyze, display and store the output pulse rate transmitted from the wireless communication module 41. The audio output unit 42 outputs the output pulse rate in an audio manner. The micro projection unit 43 outputs the output pulse rate as an image formed by lights projecting out from the micro projection unit 43 to a display area on the eyeglass frame.
The light source 2 is used for emitting light to veins and capillary blood vessels under a user's skin. In this embodiment, the light source 2 is connected to the microprocessor 1 via a variable resistor 6. The light source 2 in this embodiment comprises two LEDs which operates at a wavelength between 400nm and 900nm. The light source 2 and the photo sensing unit 3 are positioned spaced apart from each other by 2mm with a light blocker 8 positioned therebetween to prevent light trom the light source 2 from directly entering the photo sensing unit 3, thus ensuring light sensed by the photo sensing unit 3 comes from the reflection of the skin, thereby improving accuracy of the pulse rate measurement. The light blocker 8 is made ot epoxy resin which is dark in color, soft and elastic, as well as electrically insulative. The dark color prevents light from the light source 2 from directly entering the photo sensing unit 3, thus ensuring light sensed by the photo sensing unit 3 comes from the reflection of the skin, thereby improving accuracy of the pulse rate measurement. The soft and elastic texture ensures that the light source 2 and the photo sensing unit 3 are properly isolated from each other, and properly shields the light source 2 and the photo sensing unit 3 from dust and moisture. The electrically insulative character protects the light source 2 and the photo sensing unit 3 from short circuiting.
The photo sensing unit 3 in this embodiment is either a photodiode or a phototransistor used for detecting light emitted to and reflected from the veins and capillary blood vessels. In this embodiment, as illustrated in Fig. 5, the photo sensing unit 3 outputs electronic signals in form of voltage waveform with a DC component representing ambient light intensity and an AC component representing intensity of the light reflected from the veins and capillary blood vessels; the photo sensing unit 3 is connected to the microprocessor 1 via a voltage amplifier 7 which amplifies and filters the voltage waveform of the electronic signals output from the photo sensing unit 3 for recognition by the microprocessor 1. In this embodiment, the voltage amplifier 7 is an operational amplifier which comprises an input 71, a first sub-operational amplifier 72, a first capacitor 73, a first resistor 74, a low pass filter 75, an active low pass filter 76 and an output 77. The input 71 collects the voltage waveform of the electronic signals output from the photo sensing unit 3 and connects to the first sub-operational amplifier 72. The first sub-operational amplifier 72 serves as a voltage follower which eliminates the unwanted effects due to the change of the impedance of the photo sensing unit 3. The first capacitor 73 is used to block the DC component of the voltage waveform of the electronic signals which is an unwanted signal for the measurement of the pulse rate.
The first capacitor 73 is connected to ground via the first resistor 74. The first resistor 74 is used to discharge the first capacitor 73, so that the first capacitor 73, which is charged during normal operation, will not result in additional DC for the active low pass filter 76 and hence error signal at the output 77. The low pass filter 75 is formed by a second resistor 751 and a second capacitor 752, and is used to suppress the unwanted high frequency noise from the photo sensing unit 3. The active low pass filter 76 is formed by a second sub-operational amplifier 761, a feedback resistor 762 and a feedback capacitor 763, and is used to amplify the voltage waveform for the microprocessor 1 and further suppresses the unwanted high frequency noise. The output 77 delivers the voltage waveform from the active low pass filter 76 to the microprocessor 1.
The microprocessor 1 is configured to determine if the photo sensing unit 3 is in contact with the user's skin, and if the photo sensing unit 3 is determined as being in contact with the user's skin, the microprocessor 1 is configured to adjust light intensity of the light source 2 until the microprocessor 1 successfully recognizes a predetermined number of continuous pulses and thereafter perform pulse rate calculation to obtain an output pulse rate for outputting to the output means 4. In this embodiment, the predetermined number of continuous pulses is two.
More particularly, the microprocessor 1 is configured to determine if the photo sensing unit 3 is in contact with the user's skin by determining if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit 3 is zero or below a predefined threshold; if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit 3 is zero or below a predefined threshold, it means no or very weak ambient light is detected by the photo sensing unit 3 and so the photo sensing unit 3 is determined as being in contact with the user's skin; if the voltage waveform of the DC component of the electronic signals output from the photo sensing unit 3 exceeds the predefined threshold, it means strong ambient light is detected and so the photo sensing unit 3 is determined as not being in contact with the user's skin. If the photo sensing unit 3 is determined as being in contact with the user's skin, the microprocessor 1 proceeds to recognize two continuous pulses, wherein a pulse is recognized by detecting a rising edge, a peak and a decreasing edge of the voltage waveform of the electronic signals output from the photo sensing unit 3 and amplified and filtered by the voltage amplifier 7. If the microprocessor 1 fails to recognize two continuous pulses, the microprocessor 1 adlusts light intensity of the light source 2 by adjusting resistance value of the variable resistor 6 until two continuous pulses are successfully recognized. The microprocessor 1 then performs pulse rate calculation by (i) obtaining a pulse rate for each of a predetermined number of pairs of successive pulses (which is two in this embodiment), wherein a pulse rate of each pair of successive pulses is obtained by measuring a time period in seconds between the peak of a first pulse of the pair of successive pulses and the peak of a second pulse of the pair of successive pulses and dividing 60 by the time period; (ii) obtaining the output pulse rate for outputting to the output means by averaging the pulse rates obtained for the predetermined number of pairs of successive pulses; and (Hi) if necessary, repeat (i) and (H) for a predetermined number of times (which is ten in this embodiment) to update the output pulse rate for outputting to the output means.
In this embodiment, a motion sensing unit 10 is further provided in the casing 5 for measuring motion of the user, and the output of the motion sensing unit 10 is transmitted to the output means 4.
FIGs 6a to 6c illustrate other embodiments of the present invention in which the casing 5 is in form of accessories wearable on a person's calf, wrist and upper arm respectively.
The above embodiments are the preferred embodiments of the present invention.
The above embodiments do not intend to limit the description of the present invention.
All other substantive or fundamental change, modification, replacement, combination and simplification not deviated from the spirit of the present invention should be considered alternatives with equivalent effect and should be covered by the scope of protection of the present invention.
Claims (24)
- CLAIMS1. A pulse rate measuring apparatus comprises: a microprocessor; a light source for emitting light to veins and capillary blood vessels under a user's skin which is electrically connected with the microprocessor; a photo sensing unit for detecting light emitted to and reflected from the veins and capillary blood vessels which is electrically connected with the microprocessor; an output means electrically connected with the microprocessor; a casing which accommodates the microprocessor, the light source, the photo sensing unit and the output means; wherein the microprocessor is configured to determine if the photo sensing unit is in contact with the user's skin, and if the photo sensing unit is determined as being in contact with the user's skin, the microprocessor is configured to adjust light intensity of the light source until the microprocessor successfully recognizes a predetermined number of continuous pulses and thereafter perform pulse rate calculation to obtain an output pulse rate for outputting to the output means.
- 2. The pulse rate measuring apparatus as in Claim 1, wherein the photo sensing unit outputs electronic signals in form of voltage waveform with a DC component representing ambient light intensity and an AC component representing intensity of the light reflected from the veins and capillary blood vessels.
- 3. The pulse rate measuring apparatus as in Claim 2, wherein the microprocessor is configured to determine if the photo sensing unit is in contact with the user's skin by determining if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit is zero or below a predefined threshold; if the DC component of the voltage waveform of the electronic signals output from the photo sensing unit is zero or below a predefined threshold, it means no or very weak ambient light is detected by the photo sensing unit and so the photo sensing unit is determined as being in contact with the user's skin; if the voltage waveform of the DC component of the electronic signals output from the photo sensing unit exceeds the predefined threshold, it means strong ambient light is detected and so the photo sensing unit is determined as not being in contact with the user's skin.
- 4. The pulse rate measuring apparatus as in Claim 3, wherein the light source is connected to the microprocessor via a variable resistor; the photo sensing unit is connected to the microprocessor via a voltage amplifier which amplifies and filters the voltage waveform of the electronic signals output from the photo sensing unit for recognition by the microprocessor.
- 5. The pulse rate measuring apparatus as in Claim 4, wherein the microprocessor successfully recognizes a pulse by detecting a rising edge, a peak and a decreasing edge of the voltage waveform of the electronic signals output from the photo sensing unit and amplified and filtered by the voltage amplifier.
- 6. The pulse rate measuring apparatus as in Claim 5, wherein the microprocessor adjusts light intensity of the light source by adjusting resistance value of the variable resistor.
- 7. The pulse rate measuring apparatus as in Claim 6, wherein the microprocessor performs pulse rate calculation to obtain an output pulse rate for outputting to the output means by (i) obtaining a pulse rate for each of a predetermined number of pairs of successive pulses, wherein a pulse rate of each pair of successive pulses is obtained by measuring a time period in seconds between the peak of a first pulse of the pair of successive pulses and the peak of a second pulse of the pair of successive pulses and dividing 60 by the time period; (ii) obtaining the output pulse rate for outputting to the output means by averaging the pulse rates obtained for the predetermined number of pairs of successive pulses; (iii) if necessary, repeat (i) and (ii) for a predetermined number of times to update the output pulse rate for outputting to the output means.
- 8. The pulse rate measuring apparatus as in Claim 7, wherein the voltage amplifier is an operational amplifier which comprises an input, a first sub-operational amplifier, a first capacitor, a first resistor, a low pass filter, an active low pass filter and an output; the input collects the voltage waveform of the electronic signals output from the photo sensing unit and connects to the first sub-operational amplifier; the first sub-operational amplifier serves as a voltage follower which eliminates the unwanted effects due to the change of the impedance of the photo sensing unit; the first capacitor is used to block the DC component of the voltage waveform of the electronic signals which is an unwanted signal for the measurement of the pulse rate; the first capacitor is connected to ground via the first resistor; the first resistor is used to discharge the first capacitor, so that the first capacitor, which is charged during normal operation, will not result in additional DC for the active low pass filter and hence error signal at the output; the low pass filter is formed by a second resistor and a second capacitor, and is used to suppress the unwanted high frequency noise from the photo sensing unit; the active low pass filter is formed by a second sub-operational amplifier, a feedback resistor and a feedback capacitor, and is used to amplify the voltage waveform for the microprocessor and further suppresses the unwanted high frequency noise; the output delivers the voltage waveform from the active low pass filter to the microprocessor.
- 9. The pulse rate measuring apparatus as in Claim 1, wherein the light source may comprise one or more than one light sources.
- 10. The pulse rate measuring apparatus as in Claim 1, wherein the light source operates at a wavelength between 400nm and 900nm.
- 11. The pulse rate measuring apparatus as in Claim 1, wherein the light source and the photo sensing unit are positioned spaced apart from each other, preferably by 2mm, with a light blocker positioned therebetween to prevent light from the light source from directly entering the photo sensing unit.
- 12. The pulse rate measuring apparatus as in Claim 11, wherein the light blocker is dark in color, soft and elastic, as well as electrically insulative.
- 13. The pulse rate measuring apparatus as in Claim 1, wherein the output means comprises a wireless communication module which transmits the pulse rate calculated by the microprocessor to an external device.
- 14. The pulse rate measuring apparatus as in Claim 13, wherein the external device is a personal computer or a mobile device which operates a mobile software application to analyze, display and store the pulse rate transmitted from the wireless communication module.
- 15. The pulse rate measuring apparatus as in Claim 1, wherein the output means comprises an audio output unit which outputs the output pulse rate in an audio manner.
- 16. The pulse rate measuring apparatus as in Claim 1, wherein the casing is in form of an eyeglass frame; the output means comprises a micro projection unit which outputs the output pulse rate as an image formed by lights projecting out from the micro projection unit on a display area on the eyeglass frame; the eyeglass frame has two legs, each of which is provided with an elastic protrusion; the light source and the photo sensing unit are positioned on one of the elastic protrusions facing the user's skin; the elastic protrusions serve as a clamp to ensure a close contact between the light source and the photo sensing unit and the user's temporal skin region.
- 17. The pulse rate measuring apparatus as in Claim 1, wherein the casing is in form of accessories wearable on a person's different bodily parts.
- 18. The pulse rate measuring apparatus as in Claim 17, wherein the casing is attached to adjustable strap which may be worn at different bodily parts.
- 19. The pulse rate measuring apparatus as in Claim 1, wherein a motion sensing unit is further provided in the casing for measuring motion of the user, and the output of the motion sensing unit is transmitted to the output means.
- 20. A method for measuring pulse rates which comprises the following steps: (i) emitting light from a light source to veins and capillary blood vessels under a user's skin; (ii) detecting light emitted to and reflected from the veins and capillary blood vessels by a photo sensing unit; (iii) determining if the photo sensing unit is in contact with the user's skin; (iv) adjusting light intensity of the light source until a predetermined number of continuous pulses are successfully recognized if the photo sensing unit is determined to be in contact with the user's skin; (v) performing pulse rate calculation to obtain an output pulse rate.
- 21. The method for measuring pulse rates as in Claim 20, wherein Step (ii) further comprises outputting electronic signals in form of voltage waveform with a DC component representing ambient light intensity and an AC component representing intensity of the light reflected from the veins and capillary blood vessels by the photo sensing unit.
- 22. The method for measuring pulse rates as in Claim 21, wherein Step (iii) further comprises determining if the DC component of the voltage waveform ot the electronic signal output from the photo sensing unit is zero or below a predefined threshold; if the DC component of the voltage waveform of the electronic signal output from the photo sensing unit is zero or below a predefined threshold, it means no or very weak ambient light is detected by the photo sensing unit and so the photo sensing unit is determined as being in contact with the user's skin; if the DC component of the voltage waveform of the electronic signal output from the photo sensing unit exceeds the predefined threshold, it means strong ambient light is detected and so the photo sensing unit is determined as not being in contact with the user's skin.
- 23. The method for measuring pulse rates as in Claim 21, wherein recognizing a pulse comprises the steps of detecting a rising edge, a peak and a decreasing edge of the voltage waveform of the electronic signals output by the photo sensing unit and amplified and filtered by a voltage amplifier.
- 24. The method for measuring pulse rates as in Claim 21, wherein Step (v) further comprises the steps of (i) obtaining a pulse rate for each of a predetermined number of pairs of successive pulses, wherein a pulse rate of each pair of successive pulses is obtained by measuring a time period in seconds between the peak of a first pulse of the pair of successive pulses and the peak of a second pulse of the pair of successive pulses and dividing 60 by the time period; (ii) obtaining the output pulse rate for outputting to the output means by averaging the pulse rates obtained for the predetermined number of pairs of successive pulses; (iii) if necessary, repeat (i) and (ii) for a predetermined number of times to update the output pulse rate.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1317730.8A GB2519075B (en) | 2013-10-08 | 2013-10-08 | Apparatus and method for measuring pulse rate |
| CN201410318566.9A CN104510459B (en) | 2013-10-08 | 2014-07-07 | Apparatus and method for measuring pulse rate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1317730.8A GB2519075B (en) | 2013-10-08 | 2013-10-08 | Apparatus and method for measuring pulse rate |
Publications (4)
| Publication Number | Publication Date |
|---|---|
| GB201317730D0 GB201317730D0 (en) | 2013-11-20 |
| GB2519075A true GB2519075A (en) | 2015-04-15 |
| GB2519075A8 GB2519075A8 (en) | 2015-04-29 |
| GB2519075B GB2519075B (en) | 2017-12-13 |
Family
ID=49630315
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1317730.8A Expired - Fee Related GB2519075B (en) | 2013-10-08 | 2013-10-08 | Apparatus and method for measuring pulse rate |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN104510459B (en) |
| GB (1) | GB2519075B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105457254A (en) * | 2016-01-14 | 2016-04-06 | 湖南师范大学 | Intelligent training system for gymnastics training |
| WO2020070228A1 (en) * | 2018-10-04 | 2020-04-09 | Nirlus Engineering Ag | Method and measuring device for the non-invasive optical measurement of characteristics of living tissue |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105078438B (en) * | 2015-06-19 | 2017-08-11 | 京东方科技集团股份有限公司 | Pulse cycle detection device and method and wearable electronic |
| CN105094461B (en) * | 2015-07-10 | 2018-07-27 | 深圳市汇顶科技股份有限公司 | Touch pressure detection device and method |
| CN106691424A (en) * | 2015-12-18 | 2017-05-24 | 深圳市汇顶科技股份有限公司 | Method and device for detecting heart rate |
| US20170296124A1 (en) * | 2016-04-18 | 2017-10-19 | Koninklijke Philips N.V. | System and method for detecting when a sensor is worn |
| CN109863703B (en) * | 2019-01-24 | 2022-07-08 | 深圳市汇顶科技股份有限公司 | Signal conditioning method, device, chip, equipment and storage medium |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5246002A (en) * | 1992-02-11 | 1993-09-21 | Physio-Control Corporation | Noise insensitive pulse transmittance oximeter |
| EP1290975A1 (en) * | 2001-09-06 | 2003-03-12 | Seiko Instruments Inc. | Pulsimeter |
| WO2004078028A2 (en) * | 2003-02-28 | 2004-09-16 | Ken Avicola | Flashing jewelry heartbeat monitor with multiple lights |
| WO2009064979A2 (en) * | 2007-11-14 | 2009-05-22 | Conmed Corporation | Method and apparatus for processing a pulsatile biometric signal |
| EP2457502A2 (en) * | 2010-11-26 | 2012-05-30 | Spektikor OY | Disposable heart rate indicator |
| US20130131474A1 (en) * | 2011-11-22 | 2013-05-23 | Pixart Imaging Inc. | Remote controller and display system |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7171251B2 (en) * | 2000-02-01 | 2007-01-30 | Spo Medical Equipment Ltd. | Physiological stress detector device and system |
| US6594512B2 (en) * | 2000-11-21 | 2003-07-15 | Siemens Medical Solutions Usa, Inc. | Method and apparatus for estimating a physiological parameter from a physiological signal |
| JP2004065911A (en) * | 2002-06-10 | 2004-03-04 | Nippon Seimitsu Sokki Kk | Pulse meter and wearing method for the pulse meter |
| CN201104882Y (en) * | 2007-12-05 | 2008-08-27 | 沈阳东软医疗系统有限公司 | Blood oxygen saturation measurement mechanism |
| KR101040653B1 (en) * | 2009-01-21 | 2011-06-10 | 서울대학교산학협력단 | Non-contact measuring devices of pulse wave and measuring devices of oxygen saturation and blood pressure in using same |
| JP5687994B2 (en) * | 2010-11-09 | 2015-03-25 | 日本光電工業株式会社 | Biological signal measuring apparatus and biological signal measuring method |
| CN102028457B (en) * | 2010-11-24 | 2012-10-03 | 北京麦邦光电仪器有限公司 | Pulse rate measuring method and ring type pulse rate measuring meter |
| GB2494622A (en) * | 2011-08-30 | 2013-03-20 | Oxitone Medical Ltd | Wearable pulse oximetry device |
-
2013
- 2013-10-08 GB GB1317730.8A patent/GB2519075B/en not_active Expired - Fee Related
-
2014
- 2014-07-07 CN CN201410318566.9A patent/CN104510459B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5246002A (en) * | 1992-02-11 | 1993-09-21 | Physio-Control Corporation | Noise insensitive pulse transmittance oximeter |
| EP1290975A1 (en) * | 2001-09-06 | 2003-03-12 | Seiko Instruments Inc. | Pulsimeter |
| WO2004078028A2 (en) * | 2003-02-28 | 2004-09-16 | Ken Avicola | Flashing jewelry heartbeat monitor with multiple lights |
| WO2009064979A2 (en) * | 2007-11-14 | 2009-05-22 | Conmed Corporation | Method and apparatus for processing a pulsatile biometric signal |
| EP2457502A2 (en) * | 2010-11-26 | 2012-05-30 | Spektikor OY | Disposable heart rate indicator |
| US20130131474A1 (en) * | 2011-11-22 | 2013-05-23 | Pixart Imaging Inc. | Remote controller and display system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105457254A (en) * | 2016-01-14 | 2016-04-06 | 湖南师范大学 | Intelligent training system for gymnastics training |
| WO2020070228A1 (en) * | 2018-10-04 | 2020-04-09 | Nirlus Engineering Ag | Method and measuring device for the non-invasive optical measurement of characteristics of living tissue |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104510459A (en) | 2015-04-15 |
| GB2519075A8 (en) | 2015-04-29 |
| CN104510459B (en) | 2017-04-12 |
| GB2519075B (en) | 2017-12-13 |
| GB201317730D0 (en) | 2013-11-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| GB2519075A (en) | Apparatus and method for measuring pulse rate | |
| US12011292B2 (en) | Proximity sensor in pulse oximeter | |
| CN106231995B (en) | Pulse wave propagation time measuring device and living body state estimating device | |
| US11009390B2 (en) | Methods and systems for modulation and demodulation of optical signals | |
| US10881310B2 (en) | Motion artifact mitigation methods and devices for pulse photoplethysmography | |
| WO2018036474A1 (en) | Heart rate measurement method and device, and wearable apparatus | |
| US11071466B2 (en) | Portable device and blood pressure measurement method | |
| EP3106086B1 (en) | Photoelectric-type pulse signal measurement method and measurement device | |
| CN110300543B (en) | Wireless vital sign monitoring | |
| WO2017074713A1 (en) | Non-invasive continuous blood pressure monitoring with reduced motion artifacts | |
| KR101258203B1 (en) | cradle device for sensing bio-electric signal and portable device for analyzing the bio-electric signal | |
| KR20170076329A (en) | Oxygen saturation measuring apparatus and oxygen saturation measuring method thereof | |
| US9668698B2 (en) | Monitoring device and method for compensating non-linearity effects in vital signs monitoring | |
| KR100800075B1 (en) | Method and apparatus for measuring heart rate | |
| CN204797827U (en) | Reflective photoelectric sensor , pulse cycle detection equipment and wearable electronic equipment | |
| KR101950555B1 (en) | Biological signal measuring system including antiarrhythmic using Smart Scale | |
| CN204293137U (en) | A kind of human health information checkout gear | |
| CN203914906U (en) | A kind of electrocardio testing circuit and electronic equipment | |
| CN212729774U (en) | Human body multi-parameter monitoring terminal based on mobile phone | |
| CN115633947B (en) | Wearable blood pressure monitoring device and blood pressure monitoring method | |
| Verma et al. | Real time optical heart rate monitor | |
| KR100928421B1 (en) | Apparatus for detecting breth and heart beat signal using LC oscillator and method there processing signal | |
| CN109688929B (en) | Concentration measuring device and concentration measuring method | |
| KR100193878B1 (en) | Wrist portable pulse device | |
| KR102720653B1 (en) | Electronic device for measuring biometric information and method of operating the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20180313 |