JP2018153555A - Pulse wave velocity measurement system, imaging device and pulse wave velocity measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve pulse wave velocity measurement accuracy.SOLUTION: A pulse wave velocity measurement system 1 includes: an imaging device 11 performing imaging to generate image data continuous in time series; and a control device 12 detecting a human body portion from the image data, determining a blood flow direction according to the human body portion, determining two measurement portions having the same blood flow direction from the human body portion, detecting a pulse wave of each of the measurement portions on the basis of change in pixel values of the two measurement portions on the basis of the variation of pixel values of the two measurement portions, and calculating a pulse wave velocity on the basis of time difference between the pulse waves of the two measurement portions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pulse wave velocity measurement system, an imaging device, and a pulse wave velocity measurement method.

  A pulse wave velocity (PWV) is used as one of the parameters for quantitatively diagnosing the progress of arteriosclerosis (blood vessel age). The harder (aging) the blood vessel, the faster the pulse wave velocity.

  The pulse wave propagation velocity is calculated based on the time difference between the pulse waves measured at two parts of the human body and the distance between the two parts. In Patent Documents 1 and 2, two faces and hands are simultaneously captured by a camera, and pulse waves of the face and hand are detected based on temporal pixel value changes in the image data, and based on the time difference between the pulse waves. A system for measuring pulse wave velocity is disclosed.

International Publication No. 2014/136310 JP 2014-198199 A

  However, since the blood flow direction is different between the face and the hand, the measurement accuracy of the pulse wave velocity may be lowered.

  One embodiment of the present disclosure discloses a pulse wave velocity measurement system, an imaging apparatus, and a pulse wave velocity measurement method that can improve the measurement accuracy of the pulse wave velocity.

  A pulse wave velocity measurement system according to an aspect of the present disclosure includes an imaging device that performs imaging and generates continuous image data in time series, detects a human body part from the image data, and detects the human body part. Accordingly, a blood flow direction is determined, two measurement parts having the same blood flow direction are determined from the parts of the human body, and a pulse wave of each measurement part is determined based on a pixel value change of the two measurement parts. A pulse wave velocity calculating device that detects and calculates a pulse wave velocity based on a time difference between the pulse waves at the two measurement sites.

  An imaging apparatus according to an aspect of the present disclosure performs imaging, generates an image data that is continuous in time series, detects a human body part from the image data, and performs blood flow according to the human body part Determining a direction, determining two measurement parts having the same blood flow direction from the parts of the human body, detecting a pulse wave of each measurement part based on a pixel value change of the two measurement parts, And a processor for calculating a pulse wave propagation velocity based on a time difference between pulse waves at two measurement sites.

  A pulse wave velocity measurement method according to an aspect of the present disclosure performs imaging, generates time-series continuous image data, detects a human body part from the image data, and detects blood according to the human body part. Determining a flow direction, determining two measurement parts having the same blood flow direction from the parts of the human body, detecting a pulse wave of each measurement part based on a pixel value change of the two measurement parts, And calculating a pulse wave velocity based on a time difference between pulse waves at the two measurement sites.

  According to one aspect of the present disclosure, it is possible to improve the measurement accuracy of the pulse wave velocity.

The figure which shows the structure of the pulse wave velocity measurement system which concerns on Embodiment 1 of this invention. FIG. 3 is a flowchart showing a pulse wave velocity measurement method according to Embodiment 1 of the present invention. The figure which shows the blood flow direction of the face determined with the pulse wave velocity measurement system which concerns on Embodiment 1 of this invention The figure which shows the blood flow direction of the hand determined with the pulse wave velocity measurement system which concerns on Embodiment 1 of this invention The figure which shows the measurement site | part of the face determined with the pulse wave velocity measurement system which concerns on Embodiment 1 of this invention The figure which shows the measurement site | part of the hand determined with the pulse wave velocity measurement system which concerns on Embodiment 1 of this invention The figure which shows the pulse wave detected by the pulse wave velocity measurement system which concerns on Embodiment 1 of this invention The figure which shows the structure of the pulse wave velocity measurement system which concerns on Embodiment 2 of this invention. The figure which shows the structure of the imaging device which concerns on Embodiment 3 of this invention. The figure which shows the structure of the pulse wave velocity measurement system which concerns on Embodiment 4 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
<Configuration of pulse wave velocity measurement system>
The configuration of the pulse wave velocity measurement system 1 according to Embodiment 1 of the present invention will be described in detail below with reference to FIG.

  The pulse wave propagation velocity measurement system 1 includes an imaging device 11, a control device 12, and a display device 13.

  The imaging device 11 is a high-sensitivity camera of 1000 fps (frame per second) or more, performs imaging under the control of the control device 12, generates time-series continuous image data, and outputs the image data to the control device 12.

  The control device 12 detects a human body part from the image data input from the imaging device 11, determines a blood flow direction according to the detected human body part, and the blood flow direction is the same among the detected human body parts. Two measurement sites are determined. And the control apparatus 12 detects the pulse wave of each measurement part based on the pixel value change of two determined measurement parts, and calculates a pulse wave propagation speed based on the time difference of the pulse wave in two determined measurement parts To do.

  The control device 12 performs control to display an image of the image data input from the imaging device 11 on the display device 13.

  The display device 13 displays an image captured by the imaging device 11 under the control of the control device 12.

<Configuration of control device>
Next, the internal configuration of the control device 11 according to Embodiment 1 of the present invention will be described in detail with reference to FIG.

  The control device 11 includes an imaging instruction unit 111, a storage unit 112, an operation unit 113, a display instruction unit 114, and a CPU 115.

  The imaging instruction unit 111 causes the imaging device 11 to start an imaging process when a detection signal of an imaging operation is input from the operation unit 113. In addition, the imaging instruction unit 111 causes the storage unit 112 to store image data of an image captured by the imaging device 11.

  The storage unit 112 stores image data. The storage unit 112 stores a control program executed by the CPU 115.

  When the operation unit 113 detects a user's imaging operation, the operation unit 113 outputs a detection signal of the imaging operation to the imaging instruction unit 111. When the operation unit 113 detects a display operation of the user, the operation unit 113 outputs a display operation detection signal to the display instruction unit 114.

  When a display operation detection signal is input from the operation unit 113, the display instruction unit 114 causes the display device 13 to display an image of the image data stored in the storage unit 112.

  The CPU 115 reads and executes the control program stored in the storage unit 112. In particular, the CPU 115 detects a part of the human body from the image data input from the imaging instruction unit 111 by executing a control program, determines a blood flow direction according to the detected part of the human body, and includes the detected part of the human body. To determine two measurement sites having the same blood flow direction. Then, the CPU 115 detects the pulse wave of each measurement site based on the pixel value change of the determined two measurement sites, and calculates the pulse wave propagation velocity based on the time difference between the pulse waves at the determined two measurement sites.

  The CPU 115 includes a site detection processing unit 1151, a feature extraction processing unit 1152, a blood flow direction determination processing unit 1153, a measurement site determination processing unit 1154, a pulse wave information acquisition processing unit 1155, and a heart rate acquisition processing unit 1156. , And a pulse wave velocity calculation processing unit 1157. Site detection processing unit 1151, feature extraction processing unit 1152, blood flow direction determination processing unit 1153, measurement site determination processing unit 1154, pulse wave information acquisition processing unit 1155, heart rate acquisition processing unit 1156, and pulse wave propagation velocity calculation processing unit 1157 Is configured as a function block when the CPU 115 executes the control program.

  The part detection processing unit 1151 analyzes the image data stored in the storage unit 112 and detects a part of the human body from the image data. The part detection processing unit 1151 outputs the detection result of the human body part to the feature extraction processing unit 1152 and the measurement part determination processing unit 1154.

  The feature extraction processing unit 1152 extracts from the image data stored in the storage unit 112 the feature points in the part of the human body indicated by the detection result input from the part detection processing unit 1151. The feature extraction processing unit 1152 outputs the extracted feature point information to the blood flow direction determination processing unit 1153 and the measurement site determination processing unit 1154.

  The blood flow direction determination processing unit 1153 determines the blood flow direction based on the feature point information input from the feature extraction processing unit 1152. The blood flow direction determination processing unit 1153 outputs information on the determined blood flow direction to the measurement site determination processing unit 1154.

  The measurement site determination processing unit 1154 is based on the blood flow direction information input from the blood flow direction determination processing unit 1153 and the feature point information input from the feature extraction processing unit 1152, and is stored in the storage unit 112. 2 are determined from the regions of the human body detected by the region detection processing unit 1151 in FIG. 2 in which the blood flow direction is shifted along the same blood flow direction. The measurement site determination processing unit 1154 outputs information on the determined two measurement sites to the pulse wave information acquisition processing unit 1155.

  The pulse wave information acquisition processing unit 1155 calculates the pulse wave of each measurement site based on the change in the pixel values of the two measurement sites input from the measurement site determination processing unit 1154 in the image data stored in the storage unit 112. To detect. The pulse wave information acquisition processing unit 1155 filters the detected pulse wave signal and outputs the pulse wave signal from which noise has been removed to the heart rate acquisition processing unit 1156 and the pulse wave propagation velocity calculation processing unit 1157.

  The heart rate acquisition processing unit 1156 acquires the heart rate of each measurement site based on the detection result of the pulse wave of each measurement site input from the pulse wave information acquisition processing unit 1155. The heart rate acquisition processing unit 1156 outputs the acquired heart rate of each measurement site to the pulse wave propagation velocity calculation processing unit 1157.

  The pulse wave velocity calculation processing unit 1157 performs each measurement indicated by the detection result input from the pulse wave information acquisition processing unit 1155 when the difference in heart rate between the measurement sites input from the heart rate acquisition processing unit 1156 is equal to or less than a threshold value. The pulse wave velocity is calculated based on the time difference between the pulse waves of the parts.

<Pulse wave velocity measurement method>
Next, the pulse wave velocity measurement method according to Embodiment 1 of the present invention will be described in detail with reference to FIG.

  First, the imaging device 11 starts capturing a moving image (S1).

  Next, the CPU 115 executes a face detection process for detecting a face as a human body part or a hand detection process for detecting a hand as a human body part in the part detection processing unit 1151 (S2).

  Next, the CPU 115 determines whether or not the face detection unit 1151 has detected a face or a hand (S3).

  If no face or hand is detected (S3: No), the flow returns to step S2.

  On the other hand, when a face or a hand is detected (S3: Yes), the CPU 115 extracts a feature point of the face or hand in the feature extraction processing unit 1152 (S4). Specifically, the feature extraction processing unit 1152 extracts eyes, nose, mouth, face outline, and the like as facial feature points, and detects finger, arm, and skin color portions of a human body as hand feature points.

  Next, the CPU 115 determines the blood flow direction in the blood flow direction determination processing unit 1153 (S5).

  Specifically, when the blood flow direction determination processing unit 1153 detects a face in the part detection processing unit 1151, as shown in FIG. 3A, the blood flow direction determination processing unit 1153 moves upward on a straight line orthogonal to the straight line connecting the left eye and the right eye. Is determined as the blood flow direction, or, as shown in FIG. 3B, the upper direction in the straight line connecting the mouth and the nose is determined as the blood flow direction. Alternatively, when the region detection processing unit 1151 detects a hand, the blood flow direction determination processing unit 1153 scans the image horizontally and scans the plurality of width directions of the arm (skin color) portion as shown in FIG. The midpoint P1 of the length is detected, and the direction toward the finger on the straight line connecting the detected midpoints P1 is determined as the blood flow direction.

  Next, the CPU 115 determines two measurement sites having the same blood flow direction in the measurement site determination processing unit 1154 (S6).

  Specifically, when the part detection processing unit 1151 detects a face, the measurement site determination processing unit 1154, as shown in FIG. 5, the eye, nose, mouth, and face contours extracted by the feature extraction processing unit 1152 The two parts (area 1 and area 2) that are separated from each other by a predetermined pixel and shifted in position along the blood flow direction are determined as measurement parts. Alternatively, when the site detection processing unit 1151 detects a hand, the measurement site determination processing unit 1154 is separated by a predetermined distance R1 from the midpoint P1 detected by the blood flow direction determination processing unit 1153, as shown in FIG. Further, a part centered on the two middle points is determined as a measurement part (region 1 and region 2).

  Note that the measurement site determination processing unit 1154 determines a site that is as parallel as possible to the imaging device 11 so that many pixel values of the measurement site can be acquired. Thereby, the S / N ratio of the image data generated by the imaging device 11 can be increased, and the measurement accuracy of the pulse wave velocity can be improved.

  Next, the CPU 115 detects the pulse wave of each measurement site shown in FIG. 7 based on the change in the pixel values of the two measurement sites in the pulse wave information acquisition processing unit 1155, and acquires the detected value as pulse wave information. (S7).

  Next, the CPU 115 determines whether or not the heart rate acquisition processing unit 1156 has acquired a heart rate (S8).

  If the heart rate has not been acquired (S8: No), the flow returns to step S6.

  On the other hand, when the heart rate is acquired (S8: Yes), the CPU 115 compares the heart rate of each measurement site in the heart rate acquisition processing unit 1156 (S9).

  Next, the CPU 115 determines whether or not the difference in heart rate between the measurement sites is equal to or less than a threshold value (S10).

  When the difference in the heart rate between the side parts is larger than the threshold (S10: No), the flow returns to step S9.

  On the other hand, when the difference in the heart rate at each measurement site is equal to or smaller than the threshold (S10: Yes), the CPU 115 calculates the pulse wave propagation speed in the pulse wave propagation speed calculation processing unit 1157 (S11).

  Specifically, the pulse wave velocity calculation processing unit 1157 calculates the pulse wave velocity based on the phase difference ΔT1 between the pulse wave in the region 1 and the pulse wave in the region 2, as shown in FIG. Since the pulse wave propagation velocity is calculated when the difference in the heart rate at each measurement site is equal to or less than the threshold value, the reliability of the calculated value of the pulse wave propagation velocity can be improved.

<Effect>
Thus, according to the present embodiment, the blood flow direction is determined according to the human body part detected from the image data, and two measurement parts having the same blood flow direction are determined from the human body parts. A pulse wave at each measurement site is detected based on the pixel value change of the two measurement sites, and a pulse wave propagation velocity is calculated based on the time difference between the pulse waves at the two measurement sites.

  Thereby, since the pulse wave propagation velocity can be calculated from two measurement sites having the same blood flow direction, the measurement accuracy of the pulse wave propagation velocity can be improved.

(Embodiment 2)
<Configuration of pulse wave velocity measurement system>
The configuration of the pulse wave velocity measurement system 2 according to Embodiment 2 of the present invention will be described in detail below with reference to FIG.

  In FIG. 8, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The pulse wave velocity measurement system 2 includes an imaging device 11, a display device 13, a control device 21, and an irradiation device 22.

  The imaging device 11 performs imaging under the control of the control device 21 and generates time-sequential continuous image data. The imaging device 11 outputs the generated image data to the control device 21.

  The control device 21 detects a human body part from the image data input from the imaging device 11, determines a blood flow direction according to the detected human body part, and the blood flow direction is the same among the detected human body parts. Two measurement sites are determined. The control device 21 detects the pulse wave of each measurement site based on the pixel value change of the determined two measurement sites, and calculates the pulse wave propagation velocity based on the time difference between the pulse waves at the determined two measurement sites. The control device 21 performs control to display the image of the image data input from the imaging device 11 on the display device 13.

  The display device 13 displays an image captured by the imaging device 11 under the control of the control device 21.

  The irradiation device 22 irradiates the human body excluding the eyes under the control of the control device 21. The irradiation device 22 is a projector capable of altitude projection, for example.

<Configuration of control device>
The configuration of the control device 21 according to Embodiment 2 of the present invention will be described in detail below with reference to FIG.

  The control device 21 shown in FIG. 8 adopts a configuration in which an irradiation instruction unit 211 is added to the control device 11 shown in FIG.

  The operation unit 113 detects an imaging operation and outputs a detection signal of the imaging operation to the imaging instruction unit 111. The operation unit 113 detects a display operation and outputs a display operation detection signal to the display instruction unit 114. The operation unit 113 detects an irradiation operation and outputs a detection signal of the irradiation operation to the irradiation instruction unit 211.

  The irradiation instruction unit 211 causes the irradiation device 22 to irradiate the human body when a detection signal of the irradiation operation is input from the operation unit 113.

  Note that the pulse wave velocity measurement method according to the present embodiment is the same method as in FIG.

  According to the present embodiment, in addition to the effects of the first embodiment, the pulse wave propagation speed can be calculated without bothering the user by imaging while irradiating the human body with the irradiation device 22. it can.

(Embodiment 3)
<Configuration of imaging device>
The configuration of the imaging apparatus 3 according to Embodiment 3 of the present invention will be described in detail below with reference to FIG.

  9, parts having the same configuration as in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  The imaging device 3 includes a storage unit 112, an operation unit 113, a CPU 115, an imaging unit 301, a display unit 302, and an irradiation unit 303. The imaging device 3 is a high-sensitivity camera of about 1000 fps (frame per second), for example.

  The operation unit 113 detects an imaging operation and outputs a detection signal of the imaging operation to the imaging unit 301. The operation unit 113 detects a display operation and outputs a display operation detection signal to the display unit 302. The operation unit 113 detects the irradiation operation and outputs a detection signal of the irradiation operation to the irradiation unit 303.

  The imaging unit 301 performs imaging when a detection signal of the imaging operation is input from the operation unit 113, and generates time-series continuous image data. The imaging unit 301 stores the generated image data in the storage unit 112.

  The display unit 302 displays an image of image data stored in the storage unit 112 when a display operation detection signal is input from the operation unit 113.

  The irradiation unit 303 irradiates the human body excluding the eyes when an irradiation operation detection signal is input from the operation unit 113.

  Note that the pulse wave velocity measurement method according to the present embodiment is the same method as in FIG.

  According to the present embodiment, in addition to the effect of the first embodiment, it is possible to calculate the pulse wave propagation velocity without bothering the user by imaging while irradiating the human body with the irradiation unit 303. it can.

  In addition, according to the present embodiment, the pulse wave propagation velocity can be measured only by the imaging device 3, so that the number of devices can be reduced and the pulse wave propagation velocity can be measured at low cost.

(Embodiment 4)
<Configuration of pulse wave velocity measurement system>
The configuration of the pulse wave velocity measurement system 4 according to Embodiment 4 of the present invention will be described in detail below with reference to FIG.

  The pulse wave velocity measurement system 4 includes an imaging device 41 and an irradiation device 42.

  The imaging device 41 performs imaging and generates image data continuous in time series. The imaging device 41 detects a human body part from the generated image data, determines a blood flow direction according to the detected human body part, and two measurement parts having the same blood flow direction from the detected human body parts To decide. The imaging device 41 detects the pulse wave of each measurement part based on the determined pixel value change of the two measurement parts, and calculates the pulse wave propagation velocity based on the time difference between the pulse waves at the two measured measurement parts. The imaging device 41 displays an image of the generated image data.

  The irradiation device 42 irradiates the human body excluding the eyes under the control of the imaging device 41. The irradiation device 42 is a projector capable of altitude projection, for example.

<Configuration of imaging device>
The configuration of the imaging device 41 according to Embodiment 4 of the present invention will be described in detail below with reference to FIG.

  10, parts having the same configuration as in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  The imaging device 41 includes a storage unit 112, an operation unit 113, a CPU 115, an imaging unit 411, a display unit 412, and an irradiation instruction unit 413. The imaging device 41 is a high-sensitivity camera of about 1000 fps (frame per second), for example.

  The operation unit 113 detects an imaging operation and outputs a detection signal of the imaging operation to the imaging unit 411. The operation unit 113 detects a display operation and outputs a display operation detection signal to the display unit 412. The operation unit 113 detects an irradiation operation and outputs a detection signal of the irradiation operation to the irradiation instruction unit 413.

  The imaging unit 411 performs imaging when a detection signal of the imaging operation is input from the operation unit 113, and generates time-series continuous image data. The imaging unit 411 stores the generated image data in the storage unit 112.

  The display unit 412 displays an image of image data stored in the storage unit 112 when a display operation detection signal is input from the operation unit 113.

  The irradiation instruction unit 413 causes the irradiation device 42 to irradiate the human body when a detection signal of the irradiation operation is input from the operation unit 113.

  Note that the pulse wave velocity measurement method according to the present embodiment is the same method as in FIG.

  According to the present embodiment, in addition to the effects of the first embodiment, it is possible to calculate the pulse wave velocity without bothering the user by imaging while irradiating the human body with the irradiation device 42. it can.

  In addition, according to the present embodiment, the pulse wave propagation velocity can be measured by the imaging device 41 and the irradiation device 42. Therefore, the number of devices can be reduced compared to the first embodiment, and the pulse wave propagation velocity can be measured at a low cost. Can do.

  The present invention is not limited to the above-described embodiments in terms of the type, arrangement, number, etc. of the members, and departs from the gist of the invention, such as appropriately replacing the constituent elements with those having the same operational effects. It can change suitably in the range which does not.

  Specifically, in Embodiment 1 to Embodiment 4 above, the measurement site is determined from the face or hand, but a human body region other than the face and hand can be determined as the measurement site.

  In the first to fourth embodiments, the pulse wave propagation velocity is calculated based on the time difference between the pulse waves at the two measurement sites. However, based on the time difference between the pulse waves at three or more measurement sites. Thus, the pulse wave propagation velocity may be calculated. Thereby, the calculation accuracy of the pulse wave propagation velocity can be improved.

  The present invention is suitable for a pulse wave velocity measurement system and a pulse wave velocity measurement method.

1, 2, 4 Pulse wave velocity measurement system 3, 11, 41 Imaging device 12, 21, Control device 13 Display device 22, 42 Irradiation device 111 Imaging instruction unit 112 Storage unit 113 Operation unit 114 Display instruction unit 115 CPU
211, 413 Irradiation instruction unit 301, 411 Imaging unit 302, 412 Display unit 303 Irradiation unit 1151 Site detection processing unit 1152 Feature extraction processing unit 1153 Blood flow direction determination processing unit 1154 Measurement site determination processing unit 1155 Pulse wave information acquisition processing unit 1156 Heart rate acquisition processing unit 1157 Pulse wave velocity calculation processing unit

Claims (8)

An imaging device that performs imaging and generates time-series continuous image data;
A human body part is detected from the image data, a blood flow direction is determined according to the human body part, two measurement parts having the same blood flow direction are determined from the human body parts, and the two A pulse wave velocity calculating device that detects a pulse wave of each measurement region based on a pixel value change of the measurement region and calculates a pulse wave propagation velocity based on a time difference between the pulse waves in the two measurement regions;
A pulse wave velocity measurement system comprising: Extracting a feature point in the part of the human body from the image data stored in the storage unit, and determining a blood flow direction based on the feature point;
The pulse wave velocity measurement system according to claim 1. The part of the human body is the face;
Extract eyes, nose and mouth as feature points of the face,
In the straight line orthogonal to the straight line connecting the left eye and the right eye, the upper direction is determined as the blood flow direction, or in the straight line connecting the mouth and the nose, the upper direction is determined as the blood flow direction.
The pulse wave velocity measurement system according to claim 2. The human body part is a hand;
Extract fingers and arms as feature points of the hand,
The image is scanned horizontally to detect the midpoint of the lengths of the plurality of width directions of the arm portion, and the direction toward the finger in the straight line connecting the midpoints is determined as the blood flow direction.
The pulse wave velocity measurement system according to claim 2. The imaging device is a high-sensitivity camera of 1000 fps or higher.
The pulse wave velocity measurement system according to any one of claims 1 to 4. An irradiation device for irradiating the human body excluding the eyes while the imaging device is imaging;
The pulse wave velocity measurement system according to any one of claims 1 to 5. An imaging unit that performs imaging and generates time-series continuous image data;
A human body part is detected from the image data, a blood flow direction is determined according to the human body part, two measurement parts having the same blood flow direction are determined from the human body parts, and the two A processor that detects a pulse wave of each measurement site based on a pixel value change of the measurement site, and calculates a pulse wave velocity based on a time difference between the pulse waves in the two measurement sites;
An imaging apparatus comprising: Take an image,
Generate time-series continuous image data,
Detecting a part of the human body from the image data,
Determining the direction of blood flow according to the part of the human body,
Determining two measurement sites having the same blood flow direction from the regions of the human body;
Detecting a pulse wave of each measurement region based on the pixel value change of the two measurement regions;
Calculating a pulse wave velocity based on a time difference between pulse waves at the two measurement sites;
Pulse wave velocity measurement method.

Images