JP2013111444A - Device for determination of hemostasis state, pulse wave measurement device and method for determination of hemostasis state - Google Patents

Abstract

A technique for determining whether a measurement site is congested is provided.
A congestion determination apparatus includes a vein detection unit that detects a diameter of a vein located at a measurement site for measuring a pulse wave, and information indicating the diameter of the vein detected by the vein detection unit under a predetermined condition. And the vein diameter detected by the vein detection unit and the information stored in the storage unit are compared at a predetermined timing, and according to the amount of change in the diameter of the vein, A determination unit that determines whether or not the measurement site is congested.
[Selection] Figure 1

Description

  The present invention relates to a congestion determination apparatus, a pulse wave measurement apparatus, and a congestion determination method.

As a method for detecting a pulse wave in a living body, particularly a human body, a pulse wave measuring method using photoelectric conversion has been used. In this method, light having a wavelength that is easily absorbed by blood is emitted from a light-emitting element such as a light-emitting diode, and the light scattered by tissue in the living body after passing through or entering the living body, such as a photodiode or a phototransistor Light is received by the light receiving element. Then, the pulse wave is detected by converting the received light into an electric signal. The artery repeats expansion and contraction at the same cycle as the heartbeat, but the absorption of light entering the living body is greater when the artery is expanding than when the artery is expanding and contracting. The intensity of light received by the element changes according to the pulsation. That is, the amount of absorption of light emitted from the light emitting element increases or decreases in the same cycle as the cycle of blood vessel expansion and contraction, and the intensity of reflected light changes according to the increase or decrease. As a technique using such a change, for example, Patent Document 1 discloses a heartbeat of a measurement subject based on a time difference between reference points representing a predetermined amplitude value of a photoelectric pulse wave detected by a photoelectric pulse wave sensor. A technique for sequentially calculating the number is disclosed. Patent Document 2 discloses a technique for obtaining a pulse rate based on a detected photoelectric pulse wave. Patent Document 3 discloses a technique for measuring a photoelectric pulse wave and performing multifaceted data analysis corresponding to a plurality of different cases based on measurement data related to the measured photoelectric pulse wave.

JP-A-10-118038 JP 2003-169780 A JP 2007-117591 A

By the way, for example, when the measurement subject is hanging his arm downwards for a long time, when the blood perfusion of the measurement subject is affected by gravity, the periphery of the measurement site becomes congested and the pulse wave measurement is adversely affected. May affect.
The present invention provides a technique for determining whether or not a measurement site is congested.

The blood congestion determination apparatus according to the present invention includes a vein detection unit that detects a diameter of a vein located at a measurement site for measuring a pulse wave, and information indicating the diameter of the vein detected by the vein detection unit under a predetermined condition. And the vein diameter detected by the vein detection unit and the information stored in the storage unit are compared at a predetermined timing, and according to the amount of change in the diameter of the vein, And a determination unit that determines whether or not the measurement site is congested. According to this configuration, it can be determined whether or not the measurement site is congested.

Further, the pulse wave measuring device according to the present invention includes the above stasis determination device, a light emitting unit that irradiates light of a predetermined wavelength to the measurement site, and light irradiated to the measurement site passes through the measurement site. Alternatively, a light receiving unit that outputs a measurement signal based on the amount of received light of the reflected light, a generation unit that generates a pulse wave signal indicating a pulse wave based on the measurement signal output from the light receiving unit, and a determination result of the determination unit Accordingly, a control unit that controls at least one of light emission of the light emitting unit and processing performed by the generation unit may be provided. According to this configuration, it is possible to control the content of the pulse wave measurement process according to whether or not the measurement site is congested.

In the pulse wave measurement device according to the present invention, in the pulse wave measurement device, when the diameter of the vein is larger than a predetermined threshold, the determination unit is in a congested state. It is good also as determining. According to this configuration, it is possible to more suitably determine whether or not the blood is congested.

In the pulse wave measurement device according to the present invention, in the pulse wave measurement device, the control unit may increase the light emission amount of the light emitting unit when the determination result of the determination unit is positive. Good. According to this configuration, the pulse wave can be easily measured even in a congested state.

Further, the pulse wave measuring device according to the present invention is the above pulse wave measuring device, wherein the fluctuation range of the amplitude of the pulse wave signal with respect to the reference signal indicating the measurement result of the pulse wave in the non-congested state is within a predetermined range. A second determination unit that determines whether the measurement site is in a congested state according to the amount of change in the diameter of the vein and the determination result of the second determination unit. It may be determined whether or not there is. According to this configuration, it is possible to more suitably determine whether or not the blood is congested.

In addition, the congestion determination method according to the present invention includes a first vein detection step for detecting a diameter of a vein located at a measurement site for measuring a pulse wave under predetermined conditions, and the first vein detection step. A storage step of storing in the storage unit information indicating the diameter of the vein detected in
A second vein detection step for detecting a diameter of a vein located at the measurement site, a diameter of the vein detected in the second vein detection step, and information stored in the storage unit are determined in advance. And a determination step of determining whether or not the measurement site is congested in accordance with a change amount of the diameter of the vein in comparison with timing. According to this configuration, it can be determined whether or not the measurement site is congested.

The figure showing the external appearance of a pulse wave measuring device. The block diagram which shows the structural example of a pulse-wave measuring apparatus. The functional block diagram of a control part. The figure which shows an example of the vein image | photographed by the vein imaging part The operation | movement flowchart showing operation | movement of a pulse-wave measuring apparatus. The figure explaining the attitude | position of a measurement site | part. (A) is a figure which shows the example of a waveform of the measurement signal of a pulse wave. (B) is a figure which shows the waveform of the movement standard deviation based on the measurement signal of (a).

<Configuration>
FIG. 1 is a diagram illustrating an appearance of a pulse wave measurement device according to the present embodiment. FIG. 1A is a view of the pulse wave measuring device 1 as viewed from above. The pulse wave measuring device 1 is configured by connecting a device main body 10 attached to a wrist of a living body 2 and a pulse wave sensor 20 attached to a measurement site for measuring a pulse wave by a cable 30. In the present embodiment, the pulse wave sensor 20 is fixed to the palm side of the base of the index finger by a band 40 as shown in FIG. The apparatus main body 10 is provided with an operation switch 16 for operating the display 15 and the pulse wave measuring apparatus 1. In the present embodiment, the apparatus main body 10 functions as a congestion determination apparatus of the present invention. Hereinafter, each component of the pulse wave measuring device 1 will be described in the order of the pulse wave sensor 20 and the device main body 10.

FIG. 2 is a block diagram showing the configuration of the pulse wave measuring device 1. In the figure, the light emitting / receiving unit 210.
Includes a light emitting element 211 such as an LED (Light Emitting Diod) that emits light having a wavelength of green light, and a light receiving element 212 such as a photodiode that receives green light. The light emitting element 211 is an example of a light emitting unit according to the present invention. The light receiving element 212 receives the reflected light reflected by the measurement site by the light emitted from the light emitting element 211, and outputs a signal corresponding to the amount of light received. The light receiving element 212 is an example of a light receiving unit according to the present invention. The drive unit 220 includes the light emitting element 21.
A control signal for controlling the light emission intensity and the light emission timing is supplied from an analog control circuit (not shown), and a current having a magnitude corresponding to the amplitude of the control signal is supplied to the light emitting element 211 of the light receiving and emitting unit 210.

In FIG. 1B, a portion of the pulse wave sensor 20 that is in contact with the measurement site (finger) is provided with a transmission plate (not shown) that transmits light, such as a glass plate, below the transmission plate. A light emitting / receiving unit 210 is provided. The light emitting element 211 is fixed so that the direction of the transmission plate is the optical axis direction, and the light receiving element 212 is fixed so that the light receiving surface faces the direction of the transmission plate. Light emitting element 2
11 is transmitted through the transmission plate and irradiated to the measurement site, and the light reflected from the measurement site is received by the light receiving element 212 through the transmission plate. The light receiving element 212 sends a current measurement signal having a magnitude corresponding to the amount of received light to the apparatus body 10 via the cable 30.

The vein imaging unit 230 includes a light emitting element 231 that emits near infrared light, and a light emitting element 231.
CCD (Charge C) that receives reflected light of near-infrared light emitted by and outputs a signal according to the amount of light received
oupled Device) and a sensor element 232 such as an image sensor. Sensor element 2
32, a measurement signal of a current having a magnitude corresponding to the amount of received light is sent via the cable 30 to the apparatus body 10.
To send. The method for detecting the position of the vein with near-infrared light is as follows. Hemoglobin in red blood cells flowing into the veins has lost oxygen. This hemoglobin (reduced hemoglobin) absorbs near infrared rays. Light in the near-infrared region with a wavelength of 700 to 1200 nm is well transmitted through living tissue and reacts with hemoglobin in blood flowing through veins. For this reason, when near-infrared rays are applied to the measurement site, only the portion where the vein is present is less reflected and appears dark on the image. That is, the position of the vein can be recognized by the intensity of the reflected near infrared rays. In the present embodiment, a variation in the diameter of the vein recognized in this way is detected and used to determine the presence or absence of congestion.

As shown in FIG. 2, the apparatus body 10 includes a control unit 110, a signal processing unit 120, and a display unit 150.
, An operation unit 160 and a storage unit 180. The control unit 110 is a CPU (Central Processi
ng Unit) and memory (ROM (Read Only Memory) and RAM (Random Access Memory))
The CPU executes a control program stored in the ROM to control each unit connected to the control unit 110. Specifically, the control unit 110 performs a determination process for determining whether or not the measurement site is congested and an output process for outputting a pulse wave signal corresponding to the state of the measurement site. Details of the function of the control unit 110 will be described later.

The signal processing unit 120 obtains and amplifies a measurement signal output from the light emitting / receiving unit 210 of the pulse wave sensor 20 and an A / A that quantizes the amplified signal at a predetermined sampling frequency. And a D conversion circuit (not shown). The clock unit 130 is a clock supply unit 1
The time is counted by counting 40 clock signals. The clock supply unit 140 includes an oscillation circuit and a frequency dividing circuit. The clock supply unit 140 supplies a reference clock signal to the control unit 110 by the oscillation circuit, and generates a time measuring clock signal for time measurement by the frequency dividing circuit to the control unit 110. Supply. The display unit 150 includes a display 15, and displays various images such as time information measured by the time measuring unit 130, a menu screen for measuring pulse waves, and measurement results under the control of the control unit 110. The operation unit 160 includes an operation switch 16 and sends an operation signal indicating that the operation switch 16 has been operated to the control unit 110. The storage unit 180 stores various data such as threshold data used in a determination process described later. The storage unit 180 has a reference value storage area 181 for storing a reference value of the diameter of the vein used in the determination process described later.

FIG. 3 is a diagram illustrating a functional block for realizing the functions of determination processing and output processing in the control unit 110 and another part of the configuration. In the figure, the vein detection unit 111, the determination unit 112,
The pulse wave generation unit 113 and the measurement control unit 114 are realized by the control unit 110 reading and executing a computer program stored in the ROM. Vein detector 111
Is an example of a vein detection unit according to the present invention, and detects the shape of a vein located at a measurement site for measuring a pulse wave in accordance with a signal output from the vein imaging unit 230. In this embodiment, the vein detection unit 111 detects the diameter of the vein (venous width) located at the measurement site in accordance with the signal output from the vein imaging unit 230.

FIG. 4 is a diagram illustrating an example of a vein imaged by the vein imaging unit 230. In the example shown in FIG. 4, the vein imaging unit 230 captures three veins v1, v2, and v3. Thus, when a plurality of veins are imaged by the vein imaging unit 230, the vein detection unit 111 identifies one of the plurality of veins and detects the width of the identified vein as the vein diameter. . In this embodiment, the vein detection unit 111 identifies the vein located at the center of the imaging range R1 (in the example illustrated in FIG. 4, the vein v2), and the identified vein diameter (FIG. 4).
In the example shown, the diameter d2) is detected. The specific mode of the vein is not limited to this. For example, the vein detection unit 111 may specify a vein located on the right side in the imaging range R1, or specify any of the photographed veins. Anything is acceptable.

In addition, as an aspect of diameter detection, for example, the vein detection unit 111 includes a vein imaging unit 2.
Depending on the signal output from 30, the diameter of the vein may be detected at a specific interval. Further, for example, the vein detection unit 111 may calculate an average value of the diameters for every predetermined period, and the calculated average value may be used as the diameter of the veins. As another example, for example, the control unit 110 may specify the maximum value or the minimum value of the diameter for each fixed period and use the specified diameter. In short, the vein detection unit 111 may be any device as long as it detects the diameter of the vein according to the signal output from the vein imaging unit 230.

The reference value storage area 181 stores information (reference value) indicating the diameter of the vein detected by the vein detection unit 111 under a predetermined condition. The determination unit 112 is an example of a determination unit according to the present invention, and compares the diameter of the vein detected by the vein detection unit 111 with the reference value stored in the reference value storage area 181 at a predetermined timing. Depending on the amount of change in vein diameter,
It is determined whether or not the measurement site is congested.

The pulse wave generator 113 is an example of a generator according to the present invention, and generates a pulse wave signal indicating a pulse wave based on the measurement signal output from the signal processor 120. More specifically, the pulse wave generator 1
13 shows the pulse interval and the pulse rate, where the peak time interval in the waveform of the measurement signal output from the signal processing unit 120 is the pulse interval, and the frequency of appearance of the peak at every predetermined time in the waveform of the measurement signal is the pulse rate. Information is output to the display unit 150. Further, the pulse wave generation unit 113 may store information indicating the pulse wave interval and the pulse rate in the storage unit 180, for example, in time series.

The measurement control unit 114 controls the light emission amount of the light emitting element 211 according to the determination result of the determination unit 112. In this embodiment, the measurement control unit 114 controls the drive unit 220 according to the determination result of the determination unit 112 so that the light emission amount of the light emitting element 211 is increased in the case of a blood congestion state.

<Operation example>
Hereinafter, an operation example of the pulse wave measuring apparatus 1 according to the present embodiment will be described. The person to be measured first inputs a reference value to the pulse wave measuring device 1 by performing pulse wave measurement in a posture that is difficult to congest, and then starts a pulse wave measurement process.

FIG. 5 is a diagram showing an operation flow of the pulse wave measuring apparatus 1. First, the measurement subject performs an operation for performing the initial setting using the operation unit 160 in a state where the measurement site is in a position where it is difficult to congest (for example, a posture in which the arm is leveled). The control unit 110 of the pulse wave measuring device 1 includes the operation unit 16.
When an operation for initial setting is accepted via 0 (step S10; YES), the process proceeds to step S11. That is, the control unit 110 irradiates near-infrared light in the vein imaging unit 230, receives light reflected by the measurement site, detects the diameter of the vein located at the measurement site based on the amount of received light, and detects the light The diameter is stored as a reference value in the reference value storage area 181 (step S11). Step S11 is an example of a first vein detection step and a storage step according to the present invention. That is, the control unit 110 detects the diameter of the vein at the measurement site based on the signal output from the vein imaging unit 230 in a state where the measurement subject is in a posture that is difficult to congest. If control unit 110 does not accept an operation for performing initial setting via operation unit 160 (step S10; NO), control unit 110 waits until the operation is performed.

6A and 6B show a state in which the measurement subject A is standing in the direction of the arrow P. FIG. 6A shows a state in which the measurement subject A is leveling the measurement site a of the apparatus main body 10, and FIG. 6B shows the measurement site A in the direction of gravity when the measurement subject A lowers his arm. It is in a state tilted to. As shown in FIG. 6B, in a posture in which the measurement site a is tilted in the direction of gravity, blood does not easily return from the fingertip toward the upper arm. Therefore, the measurement target person A performs the initial setting with the posture as shown in FIG.

When the initial setting is completed, the measurement subject performs an operation to start measuring the pulse wave. Control unit 1
10 receives an operation for measuring a pulse wave (step S12; YES), step S1
Proceed to step 3. That is, in the pulse wave sensor 20, the control unit 110 irradiates the measurement site with light, receives the light reflected by the measurement site, and starts outputting a measurement signal corresponding to the amount of received light (step S13). The control unit 110 performs A / D conversion on the pulse wave signal output from the pulse wave sensor 20 in the signal processing unit 120, acquires time-series measurement data from the signal processing unit 120, and stores the measurement data in the RAM. The control unit 110 detects the peak time interval in the waveform of the measurement signal (measurement data) as the pulse interval, detects the frequency of appearance of the peak every predetermined time in the waveform of the measurement signal as the pulse rate, and detects the detected pulse interval and pulse rate. Are displayed on the display unit 150. If control unit 110 does not accept an operation for measuring a pulse wave via operation unit 160 (step S12; NO), control unit 110 waits until the operation is performed.

In addition, the control unit 110 starts the measurement process of the pulse wave and starts the determination process of whether or not the measurement site is congested. First, the control unit 110 detects the diameter of the vein based on the signal output from the vein imaging unit 230 (step S14). Step S14 is an example of a second vein detection step according to the present invention. The control unit 110 compares the detected diameter with the reference value detected in step S11, and determines whether or not the measurement site is congested according to the comparison result (step S15). Step S15 is an example of a determination step according to the present invention. In this determination process, for example, the control unit 110 may determine that the blood vessel is congested when the diameter of the vein is larger than a reference value by a predetermined threshold or more. Further, for example, a ratio between the detected diameter of the vein and a reference value may be calculated, and it may be determined that the blood is congested when the calculated ratio is equal to or greater than a predetermined threshold. In short, the control unit 11
As long as 0 compares the detected diameter with a reference value and determines the presence or absence of congestion according to the comparison result, any value may be used.

When it is determined that the control unit 110 is not congested (step S15; NO),
The light emission amount of the light emitting element 211 is set to a predetermined standard amount (step S16). On the other hand, when it is determined that the blood is congested (step S15; YES), the control unit 110 controls the light emitting / receiving unit 210 so that the light emission amount of the light emitting element 211 is increased (step S17).
The control unit 110 repeatedly performs the processes of steps S14 to S17 described above until an operation for ending the pulse wave measurement is performed via the operation unit 160 (step S18; NO).
When the measurement site is congested, the measurement signal may be difficult to detect. However, in this embodiment, the pulse wave signal is measured by increasing the light emission amount of the light emitting element 211 when the measurement site is congested. It becomes easy. The control unit 110 ends the process when an operation for ending the measurement of the pulse wave is performed via the operation unit 160 (step S18; YES).

As described above, in the present embodiment, the control unit 110 determines whether or not the measurement site is congested based on the output signal from the vein imaging unit 230, and the light emitting element 2 according to the determination result.
11 is controlled. In the electroencephalogram measurement apparatus, the accuracy of the measurement value may be lowered due to the influence of the blood congestion state on the pulse wave measurement. On the other hand, in this embodiment, the presence or absence of a congested state is determined based on a change in the diameter of the venous blood vessel, and the power of the light emitting element is controlled. Thereby, it becomes easy to measure a pulse wave stably.

<Modification>
The present invention is not limited to the above-described embodiment, and may be carried out by being modified as follows. Further, the following modifications may be combined.

(1) In the above-described embodiment, the pulse wave measuring device 1 shown in FIG. 1 is shown. However, the configuration of the pulse wave measuring device 1 is not limited to this, and may be another configuration. For example, the apparatus main body 10
However, it may be shaped to be worn on other parts of the body such as arms and legs. Further, for example, the device body 10 may be a device such as a mobile phone or a portable information terminal.

In the above-described embodiment, the apparatus main body 10 and the pulse wave sensor 20 are connected by the cable 30. However, the present invention is not limited to this, and the apparatus main body 10 and the pulse wave sensor 20 are connected by wireless communication. Also good. In the above-described embodiment, the pulse wave measuring device 1 is an example in which the device main body 10 and the pulse wave sensor 20 are connected by the cable 30, but the present invention is not limited thereto. And the pulse wave sensor 20 may be configured as one device. In this case, for example, the pulse wave measuring device may be configured to be worn on the wrist like a wristwatch, and the pulse wave sensor may be provided at a position where the pulse wave measuring device and the attachment site (wrist) are in contact with each other. .
Further, in the above-described embodiment, an example in which the measurement site on which the pulse wave sensor 20 is mounted is an index finger has been described, but the measurement site is not limited to this and may be another site such as the back of the hand, the wrist, or the upper arm.

(2) In the above-described embodiment, the light receiving / emitting unit 210 emits light having a wavelength of green light.
1 and a light receiving element 212 that receives light having a wavelength of green light, but the light emitted and received by the light emitting / receiving unit is not limited to green light, but other wavelengths such as blue light and infrared light. It may be light.
In the above-described embodiment, the pulse wave sensor 20 is configured to include one light emitting / receiving unit 210, but is not limited thereto, and may be configured to include a plurality of light receiving / emitting units 210. Specifically, for example, the light emitting / receiving unit that emits and receives light with a green wavelength and the light emitting / receiving unit that emits and receives light with a red wavelength are provided. May be.

(3) In the above-mentioned embodiment, it is good also as a structure which uses together the determination method which determines whether the change of the volume of the blood vessel in a measurement site | part is more than fixed. The blood vessel at the measurement site repeats expansion and contraction in the same cycle as the heartbeat, and the amount of light emitted from the light emitting element increases and decreases at the same cycle as the blood vessel expansion and contraction, and is reflected according to the increase and decrease. The light intensity changes. Therefore, the current flowing through the light receiving element has a component indicating a change in the volume of the blood vessel at the measurement site. When the measurement site is not congested, along the heartbeat rhythm, arterial blood passes from the upper arm through the measurement site to the fingertip, and venous blood flows from the fingertip through the measurement site to the upper arm.
On the other hand, in a congested state, the change in the blood volume of the arteries and veins becomes small, so the amplitude of the moving standard deviation becomes small.

FIG. 7 is a diagram illustrating a waveform of a measurement signal when a pulse wave is measured using the pulse wave measurement device 1. In this example, the measurement subject wearing the pulse wave measurement device 1 takes a posture in which the measurement site is substantially horizontal for the first 30 seconds (period A), and then places the fingertip with the measurement site facing down for 60 seconds. A series of movements (period B) was performed in which the posture toward the direction of gravity is easily congested.

In the figure, since the period A is in a resting state, the measurement signal in this period has a stable waveform with a constant period, and no blood is congested in these periods. After the period A to the period B, the amplitude gradually decreases. The period B is a posture and a resting state in which the measurement site is oriented in the direction of gravity and easy to stagnate. During this period, venous blood increases at the measurement site with the passage of time, and the light emitted from the light emitting element is absorbed according to the extinction coefficient for reduced hemoglobin contained in venous blood, and the amount of received light decreases. In addition, the blood flow volume in the arteries and veins is reduced, so that the expansion and contraction of the blood vessels is weakened.
The amplitude is 1/3 to 1/4 or less than that of the period A. This phenomenon also appears in the waveform of the moving standard deviation for the waveform data of FIG. 7A shown in FIG. The moving standard deviation represents the amount of change in the thickness of blood in the subcutaneous blood vessel at the measurement site. That is, when blood is not congested, arterial blood passes from the upper arm through the measurement site to the fingertip and venous blood flows from the fingertip through the measurement site to the upper arm along the heartbeat rhythm. On the other hand, in a congested state, the change in the blood volume of the arteries and veins becomes small, so the amplitude of the moving standard deviation becomes small. Therefore, it can be seen that the blood is congested in period B (30 to 80 seconds).

Here, an example of a specific operation in this aspect will be described below. Control unit 110
In the initial setting, the measurement signal output from the pulse wave sensor 20 is stored in the storage unit 180 as a reference signal. Then, when measuring the pulse wave, the amplitude of the measurement signal output from the pulse wave sensor 20 is obtained, and using the waveform data of the reference signal in the storage unit 180, the amplitude of the measurement signal relative to the amplitude of the reference signal is calculated. The ratio is calculated as the amplitude fluctuation range of the measurement signal. In this aspect, the fluctuation range of the measurement signal is relative to the amplitude of the measurement signal (hereinafter referred to as “reference signal”) when the pulse wave is measured in a posture in which the measurement site is leveled and the user hardly moves. It is the ratio of the amplitude of the measurement signal. Note that the fluctuation range of the measurement signal may be an index that represents a change in the amplitude of the measurement signal, such as a moving standard deviation or a moving average value of the measurement signal. When the ratio of the amplitude of the measurement signal to the amplitude of the reference signal is equal to or less than a threshold value (1/3 to 1/4), the control unit 110 determines that the change in the volume of the blood vessel at the measurement site is not a certain level or more.

In this aspect, the control unit 110 determines whether or not the measurement site is congested according to the determination result based on the amplitude ratio and the determination result of the vein diameter. More specifically, for example, the control unit 110 compares the detected diameter with a reference value, the vein diameter is larger than a predetermined threshold value, and the amplitude ratio is equal to or larger than a predetermined threshold value. In this case, it may be determined that the measurement site is congested. As described above, by using a plurality of determination conditions (determination based on the diameter of the vein and determination based on the amplitude ratio) in combination, it is possible to increase the accuracy of determination of congestion.

Note that the determination mode is not limited to this, and other determination conditions may be used in combination. Specifically, for example, the pulse wave measuring device 1 may be provided with an acceleration sensor, and the motion of the measurement subject may be detected by the acceleration sensor, and the presence or absence of congestion may be determined according to the detection result. More specifically, for example, the direction of the measurement site is detected by an acceleration sensor, it is determined whether the measurement site is in a posture that is easily congested due to the influence of gravity, and the determination result and the amount of change in the diameter of the vein Depending on the condition, the presence or absence of congestion may be determined.

(4) In the above-described embodiment, the two-dimensional image sensor is used as the sensor element of the vein imaging unit 230. However, the sensor element is not limited to this and may be a one-dimensional image sensor. Even when a one-dimensional image sensor is used, the control unit 110 detects the diameter of the vein from the image read by the image sensor, as in the above-described embodiment. In the above-described embodiment, a CC image sensor is used as the sensor element 232.
The sensor element is not limited to this. For example, CMOS (Complementary Metal
Oxide) image sensor may be used as long as it can detect the diameter of the vein.

(5) In the above-described embodiment, the control unit 110 determines the presence or absence of congestion and controls the light emission amount of the light emitting element 211 according to the determination result. However, the processing performed by the control unit 110 is not limited to this. Not exclusively. For example, when it is determined that the control unit 110 is in a congested state, pulse wave detection may be performed using light of two types of wavelengths, green light and red light. Further, for example, the control unit 110 may control the process of generating a pulse wave signal from the signal output from the signal processing unit 120 according to the presence or absence of congestion. More specifically, for example, when it is determined that the control unit 110 is in a congested state, a noise component is removed from the signal output from the signal processing unit 120 according to a predetermined algorithm. You may make it perform a filter process.

In the above-described embodiment, the control unit 110 determines the presence or absence of congestion and controls the light emission amount of the light emitting element 211 according to the determination result. However, the process performed by the control unit 110 is not limited thereto. Absent. For example, the light emission amount of the light emitting element 211 may be controlled according to the degree of congestion. More specifically, for example, the control unit 110 may perform control so that the light emission amount of the light emitting element 211 increases as the degree of congestion increases. In short, the control unit 110 may control the process for generating the measurement signal according to the determination result of the presence or absence of congestion.

(6) In the above-described embodiment, the pulse wave measurement device that determines the presence or absence of congestion and controls the light emission amount of the light emitting element according to the determination result has been described. Instead, a congestion determination device that determines the presence or absence of congestion, and a device that performs various control operations according to the determination results of the congestion determination device,
It may be configured as a separate device. In this case, for example, the congestion determination device and the pulse wave measurement device may communicate with each other by wire or wirelessly.

(7) In the above-described embodiment, the control unit 110 determines that the blood vessel is congested when the diameter of the vein is greater than a predetermined threshold value from the reference value. However, the determination mode is not limited to this. Absent. For example, it may be determined that the blood is congested when the state in which the amount of change in the diameter of the vein is equal to or greater than a predetermined threshold continues for a predetermined time or longer.

In the above-described embodiment, when a plurality of veins are imaged by the vein imaging unit 230, the control unit 110 identifies one of the plurality of imaged veins and detects the diameter. However, the detection mode is not limited to this. For example, the diameter may be detected for a part or all of the plurality of photographed veins. Specifically, for example, when three veins are photographed, the control unit 110 detects the diameters of the three veins at the time of initial setting, and uses the detected diameters as reference values as reference value storage areas 181. You may make it memorize in. In this case, at the time of measuring the pulse wave, the diameters of the three veins may be detected, and the respective diameters may be compared with the reference values. More specifically, for example, the control unit 110 may determine that the measurement site is congested when the number of veins having a diameter larger than the reference value exceeds a majority. Further, for example, when the diameters of all veins are larger than the reference value, it may be determined that the measurement site is congested.

In the above-described embodiment, the control unit 110 analyzes the image captured by the vein imaging unit 230 to detect the positional relationship of the veins in the imaging range, and detects the diameter detection position based on the detected positional relationship. May be determined. For example, even when the mounting position of the pulse wave sensor 20 has shifted, the control unit 110 can detect the diameter at the same position by analyzing the image and determining the detection position of the diameter, Thereby, the detection accuracy can be increased.

In the above-described embodiment, the example in which the threshold value for determining the presence or absence of congestion is stored in the storage unit 180 has been described. However, the user can adjust the threshold value in the storage unit 180 using the operation unit 160. You may comprise as follows. Moreover, it is good also as a structure which each memorize | stores a threshold value according to the biological body used as a measuring object.

(8) Although the pulse wave sensor 20 in the above-described embodiment has been described as receiving the reflected light of the light irradiated to the measurement site, the pulse wave sensor 20 may be configured to receive the light transmitted through the measurement site. Good.

(9) A program executed by the control unit 110 of the pulse wave measuring device 1 is read by a computer device such as a magnetic recording medium such as a magnetic tape or a magnetic disk, an optical recording medium such as an optical disk, a magneto-optical recording medium, or a semiconductor memory. It may be provided in a state stored in a possible recording medium. It is also possible to download this program via a communication network such as the Internet. Various devices other than the CPU can be applied as the control means for performing such control. For example, a dedicated processor or the like may be used.

DESCRIPTION OF SYMBOLS 1 ... Pulse wave measuring device, 2 ... Living body, 10 ... Apparatus main body, 15 ... Display, 16 ... Operation switch, 20 ... Pulse wave sensor, 30 ... Cable, 40 ... Band, 110 ... Control part, 111 ... Vein detection part, DESCRIPTION OF SYMBOLS 112 ... Determination part, 113 ... Pulse wave output part, 120 ... Signal processing part, 130 ... Timing part, 140 ... Clock supply part, 150 ... Display part, 160 ... Operation part, 180 ... Memory | storage part, 210
... light emitting / receiving unit, 220 ... driving unit

Claims (6)

A vein detector that detects the diameter of the vein located at the measurement site for measuring the pulse wave;
A storage unit for storing information indicating a diameter of the vein detected by the vein detection unit under a predetermined condition;
The vein diameter detected by the vein detection unit is compared with the information stored in the storage unit at a predetermined timing, and the measurement site is in a congested state according to the amount of change in the vein diameter. And a determination unit for determining whether or not there is a blood stasis determination device. The blood congestion determination device according to claim 1;
A light emitting unit for irradiating the measurement site with light having a predetermined wavelength;
A light receiving unit that outputs a measurement signal based on the amount of light received by the light irradiated to the measurement site transmitted or reflected by the measurement site;
A generating unit that generates a pulse wave signal indicating a pulse wave based on a measurement signal output by the light receiving unit;
A pulse wave measuring apparatus comprising: a control unit that controls at least one of light emission of the light emitting unit and processing performed by the generation unit according to a determination result of the determination unit. The pulse wave measurement device according to claim 2, wherein the determination unit determines that the measurement site is congested when the diameter of the vein is larger than a predetermined threshold value. The pulse wave measurement device according to claim 2 or 3, wherein the control unit increases the light emission amount of the light emitting unit when the determination result of the determination unit is affirmative. A second determination unit for determining whether or not a fluctuation range of the amplitude of the pulse wave signal with respect to a reference signal indicating a measurement result of the pulse wave in a non-congestive state is within a predetermined range;
The determination unit determines whether or not the measurement site is congested according to a change amount of the diameter of the vein and a determination result of the second determination unit. The pulse wave measuring device according to any one of the above. A first vein detection step for detecting a diameter of a vein located at a measurement site for measuring a pulse wave under a predetermined condition;
A storage step of storing information indicating a diameter of the vein detected in the first vein detection step in a storage unit;
A second vein detection step for detecting a diameter of a vein located at the measurement site;
The diameter of the vein detected in the second vein detection step is compared with information stored in the storage unit at a predetermined timing, and the measurement site is congested according to the amount of change in the diameter of the vein. And a determination step for determining whether or not a condition is present.

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