JP2016140373A - Pulse wave measurement device and pulse wave measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately measure a pulse wave.SOLUTION: A pulse wave measurement device includes: a plurality of bandpass filters (24a and 24b) for dividing each of a plurality of signals into a plurality of frequency bands; a correlation coefficient computation part (28) for computing a correlation coefficient indicating a correlation between the plurality of signals that pass through the bandpass filters for each of the plurality of frequency bands; and a waveform synthesis part (30) for weighting each signal that passes through the plurality of bandpass filters according to the correlation coefficient, and synthesizing waveforms of each signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pulse wave measuring device and a pulse wave measuring method.

  As a technique for measuring a pulse wave, a technique using a photoelectric pulse wave method is generally used. The photoelectric pulse wave method is a method of detecting a change in the volume of a blood vessel from a change in reflected light or transmitted light accompanying an increase or decrease in blood volume, utilizing the light absorption characteristics of blood from the visible region to the near infrared region.

  The pulse wave signal is composed of pulsating components caused by changes in blood flow corresponding to the heartbeat, and at the same time, the slow changes of various low-frequency components that are thought to be the result of breathing, sympathetic nervous system activity, and temperature regulation. It also has a baseline component. On the other hand, the body movement component, which is an artifact caused by the sensor wearing state and movement of the wearing site, has a large influence on the baseline component, and the change in the baseline component due to the influence of the body movement is superimposed on the pulse wave component. It is difficult to measure a wave signal. In order to measure an accurate pulse wave signal, it is necessary to reduce a body motion component included in the pulse wave signal.

  In Patent Document 1, a body motion detecting unit having a pair of light emitting units and a light receiving unit generates a body motion signal, and a pulse wave detecting unit having a pair of light emitting units and a light receiving unit generates a pulse wave signal. A technique for generating a pulse wave signal from which a body motion component has been removed by subtracting the body motion signal from the pulse wave signal by the comparison calculation means is described.

Japanese Patent No. 3969612 (Registered on June 15, 2007)

  However, both the pulse wave component and the body motion component are included in the signal detected by the configuration of the pair of light emitting unit and light receiving unit. That is, it is not possible to detect a signal of only a body motion component or only a pulse wave component with only one set of light emitting unit and light receiving unit. Therefore, there is an accuracy problem in the technique of using the body motion detection means or the pulse wave detection means only by the configuration of the one set of light emitting part and light receiving part described in Patent Document 1.

  In the technique described in Patent Document 1, each of the signals generated by the light receiving unit includes both a pulse wave component and a body motion component, and the comparison calculation means subtracts the body motion signal from the pulse wave signal. In the difference signal, not only the difference signal of the pulse wave component but also the difference signal of the body motion component remains. For this reason, the differential signal is not an accurate pulse wave signal. Furthermore, even if the differential signal is subjected to frequency analysis, since only the pulse wave component and the body motion component exist, it is not possible to remove only the body motion component. Further, as described above, since the differential signal is composed of the differential signal of the pulse wave component and the differential signal of the body motion component, the body motion component cannot be removed from the pulse wave component even if autocorrelation calculation is performed. Therefore, there is a problem that accurate information such as pulse waves cannot be obtained. The present invention has been made in view of the above problems, and an object thereof is to provide a pulse wave measuring device and a pulse wave measuring method capable of measuring a pulse wave more accurately than in the past. It is in.

  In order to solve the above-described problem, a pulse wave measurement device according to one aspect of the present invention includes a light emitting unit that irradiates a biological measurement site with a plurality of lights having different wavelengths, and the plurality of light received through the living body. For each of the plurality of frequency bands, a light receiving unit that receives each of the light and generates a plurality of signals corresponding to each light, a plurality of band pass filters that divide each of the plurality of signals into a plurality of frequency bands, A correlation coefficient calculation unit that calculates a correlation coefficient indicating a correlation between a plurality of signals that have passed through the band-pass filter, and for each signal that has passed through the plurality of band-pass filters, according to the correlation coefficient And a waveform synthesis unit that synthesizes the waveforms of the respective signals after weighting.

  According to one aspect of the present invention, since the signals in each frequency band are synthesized after weighting according to the correlation coefficient indicating the correlation between the plurality of signals that have passed through the bandpass filter, compared to the conventional case. There is an effect that an accurate pulse wave can be measured.

It is a block diagram which shows the structure of the pulse wave measuring device which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the measurement part which concerns on embodiment of this invention with a biological body. It is a top view which shows the structure of the measurement part which concerns on embodiment of this invention. It is a block diagram which shows the structure of the biometric information display apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of the process of biometric information measurement which concerns on embodiment of this invention.

  In the following, first, important terms and technical concepts will be described prior to specific description of embodiments of the present invention.

(Pulse wave)
When the heart's ventricle contracts rapidly, blood is pumped from the left ventricle into the aorta. Then, the aortic wall in that portion extends, accepts the pumped blood, and increases the internal pressure. The aortic wall locally extended in this manner gradually returns to its original shape while pushing blood to the periphery during the second half of the ejection period to the beginning of the next ejection period. The local arterial dilatation and the increase in the internal pressure thus generated propagate in a wave shape toward the periphery of the artery. A pressure waveform including both the forward wave coming from the heart and the reflected wave from the blood vessel bifurcation by the propagating wave is called a pulse wave.

  Further, the volume pulse wave is caused by the volume change accompanying the pressure change in the arterial blood vessel due to the wave, and the pressure pulse wave is caused by the propagation of the pressure wave in the blood vessel. In general, the detected volume pulse wave includes a photoelectric volume pulse wave using an optical method, and the detected pressure pulse wave includes a piezoelectric pressure pulse wave using a piezoelectric method. If the arterial blood vessel detection site is the same, the volume pulse wave and the pressure pulse wave are generally similar, but the waveform of the pulse wave is said to vary considerably depending on the type of blood vessel. There are two types of measurement of volume pulse wave: direct measurement and non-invasive measurement. There is photoelectric plethysmography (volume fluctuation recording method) using light as non-invasive measurement. Absorption characteristics of blood in visible region to near infrared region. Is used to detect volume change from reflected or transmitted light amount change accompanying blood volume increase / decrease, and is also called photoelectric pulse wave method. Measurement without the need for cuff pressure is possible, and it is used as a clinical test method for peripheral volume pulse waves. In the present embodiment, measurement is performed using the photoelectric pulse wave method, and the pulse wave in the present embodiment refers to that measured by the photoelectric pulse wave method.

  As will be described later, the pulse wave signal includes a pulse wave component and a body motion component, and the body motion component may vary depending on the movement of the body of the subject. For this reason, it is important how to remove the body motion component from the pulse wave signal.

(Photoelectric pulse wave method)
Photoplethysmography (PPG) is a method of measuring a pulse wave using a photoelectric pulse wave meter composed of a light emitting part such as an LED and a light receiving part such as a photodetector. Using the light absorption characteristics of blood from the visible region to the near-infrared region, a change in the volume of the blood vessel is detected from a change in reflected light or transmitted light accompanying an increase or decrease in blood volume.

(Principle of measurement by photoelectric pulse wave method)
The elements constituting the living tissue are blood, skin, fat, bone, and the like, but only blood changes as the heart beats. Arterial blood in a living body consists of a plasma component (55%) and a blood cell (cell) component (45%), and 91% of the plasma component is water. The blood cell component consists of red blood cells (96%), white blood cells (3%), and platelets (1%). There are 4-5 million red blood cells in 1 millicubic meter, and hemoglobin occupies 97% of the protein.

  Hemoglobin has the property of absorbing light, and the amount of hemoglobin changes with changes in volume of peripheral blood vessels caused by arterial pressure. Therefore, it is possible to measure the pulse wave by irradiating the light emitting part from the skin surface and obtaining the reflected or transmitted light intensity as an electrical signal by the light receiving part. In addition, the relationship between the signal output and the blood flow at the measurement site is inversely proportional to the absorption of light into the blood. If the blood flow increases, the light absorption increases and the output decreases.If the blood flow decreases, the light absorption decreases. However, the output increases. Therefore, the increase or decrease of the signal output of the light receiving unit can convert the volume change of the blood flow or the change of the blood flow volume into the increase or decrease of the output, and this appears as a pulsation component.

Embodiment 1
Hereinafter, embodiments of the present invention will be described in detail.

<Pulse wave measuring device>
In one embodiment of the present invention, a pulse wave is measured by measurement using a photoelectric pulse wave method. FIG. 1 is a block diagram showing a configuration of a pulse wave measuring apparatus 1 according to the present embodiment.

  As shown in FIG. 1, the pulse wave measuring apparatus 1 includes a measurement unit 10, an intensity correction unit 22, a first bandpass filter 24 a, a second bandpass filter 24 b, a control unit 26, and a pulse rate calculation unit 32. It is comprised including. The pulse wave measuring device 1 is wirelessly connected or wired to the biological information display device 2, and transmits a pulse wave signal or the like from the pulse wave measuring device 1 to the biological information display device 2.

(Measurement part)
FIG. 2 is a cross-sectional view showing the configuration of the measurement unit 10 together with a living body. The measurement unit 10 is used in close contact with a living body as shown in FIG. The measuring unit 10 includes a housing 12 made of a resin such as ABS (acrylonitrile butadiene styrene copolymer), a light emitting unit 14, and a light receiving unit 16.

  The housing 12 stores the light emitting unit 14 and the light receiving unit 16, and the space in the housing 12 is filled with a resin mold 18. Further, the surface of the housing 12 is provided with a plating 20 as an electrode for the light emitting unit 14 and the light receiving unit 16. In FIG. 2, the living body and the measurement unit 10 are in close contact with each other, but they may be used apart from each other, and are plated with a material having an electrical insulating property on the plating 20 and a characteristic of shielding disturbance light, such as ABS. For example, it may be formed by a technique such as painting on the surface to be brought into close contact with the 20 living body and may be in close contact with the living body.

  It is preferable that the plating 20 is formed at least at a portion where the light emitting unit and the light receiving unit are arranged in the housing 12 and inside and outside the outer edge of the housing 12.

  The light emitting unit 14 is controlled by the control unit 26 and irradiates the measurement site of the living body with a plurality of lights having different wavelengths. The light receiving unit 16 is controlled by the control unit 26, receives each of the plurality of lights received through the living body, and generates a plurality of signals corresponding to each light. An arrow in FIG. 2 schematically shows a path of light irradiated by the light emitting unit 14 and reflected by the living body. In the present embodiment, as illustrated in FIG. 2, a configuration in which the light receiving unit 16 receives reflected light from a living body will be described as an example.

  FIG. 3 is a top view illustrating the configuration of the measurement unit 10. As shown in FIG. 3, the light emitting unit 14 includes a first light emitting unit 14 a and a second light emitting unit 14 b. The 1st light emission part 14a and the 2nd light emission part 14b are good to irradiate the light from which a wavelength differs mutually. For example, the first light emitting unit 14a emits green light, and the second light emitting unit 14b emits near infrared light. More specifically, the first light emitting unit 14a may emit light with a wavelength of 495 to 570 nm, and the second light emitting unit 14b may emit light with a wavelength of 700 to 1200 nm.

  For example, the distance that becomes a natural logarithm of light at the time of incidence is 0.4 mm when green light having a wavelength of about 525 nm is incident on the living body, and near infrared light having a wavelength of about 880 nm is incident on the living body. This is 1.4 mm, which is called the penetration depth. The blood vessels to be observed differ depending on the difference in penetration depth, and the ascending arteriole is observed with green light and the aorta is observed with near-infrared light. And the signal measured by near-infrared light has a larger influence of body motion noise during exercise. Thus, due to the fact that the blood vessels to be observed are different, the artifacts superimposed on the pulse wave component also differ. In the present embodiment, artifacts can be effectively reduced by using green light and near infrared light.

  The light receiving unit 16 includes a first light receiving unit 16a and a second light receiving unit 16b. The first light receiving unit 16a receives the light irradiated by the first light emitting unit 14a and reflected by the living body. The first light receiving unit 16a generates a signal indicating the intensity of the received light at each time point (hereinafter referred to as “green signal”). The second light receiving unit 16b receives the light irradiated by the second light emitting unit 14b and reflected by the living body. In addition, the second light receiving unit 16b generates a signal indicating the intensity of the received light at each time point (hereinafter referred to as “near infrared signal”).

  In the green signal generated by the first light receiving unit 16a and the near infrared signal generated by the second light receiving unit 16b, a pulse wave component and a body motion component which is an artifact are mixed.

(Intensity correction part)
The intensity correction unit 22 receives a green signal from the first light receiving unit 16a and also receives a near infrared signal from the second light receiving unit 16b.

  Green light and near-infrared light have different wavelengths. Due to the difference in the light absorption characteristics of blood due to the difference in the wavelength of light, the intensity of the green signal and the intensity of the near-infrared signal are not uniform and there is an intensity difference. The intensity correction unit 22 corrects the intensity of the signal so that the intensity difference is approximately the same.

  For example, the intensity correction unit 22 may multiply one signal of the green signal and the near infrared signal by a coefficient having a negative correlation with the intensity of the one signal. More specifically, by calculating (calculating) a coefficient r of the signal intensity ratio shown in the following equation 1 based on each signal intensity and multiplying the near-infrared signal by this coefficient r, the signal intensity of the green signal is calculated. And adjust the signal intensity of near-infrared signal to the same level. The green signal and the near-infrared signal whose signal intensities are adjusted to the same level are supplied to the first band pass filter 24a and the second band pass filter 24b, respectively.

  Here, the bars attached to “green signal intensity” and “near infrared signal intensity” in Equation 1 indicate that the green signal intensity and the near infrared signal intensity take integral values in a predetermined period, respectively. ing.

  More specifically, the intensity correction unit 22 includes, for example, a 0.3 Hz low-pass filter, and each signal (green signal, near infrared signal) within a predetermined period acquired by the intensity correction unit 22 when the living body is at rest. ) Is subjected to signal processing using a filter for removing a DC component, for example, a 0.1 Hz high-pass filter, and then full-wave rectified (that is, an absolute value is calculated). It is good also as a structure which calculates (calculates) the said integral value of each signal strength of a near-infrared signal.

  With such a configuration, the signal intensity difference between the green signal and the near-infrared signal can be effectively adjusted so as to be approximately the same.

  The predetermined period may be, for example, 10 seconds, 15 seconds, 20 seconds, etc., but this does not limit the present embodiment.

(Band pass filter)
The first band pass filter 24 a receives the green signal output from the intensity correction unit 22. The second band pass filter 24b receives the near-infrared signal output from the intensity correction unit 22.

  Here, the above-described intensity correction is performed on at least one of the green signal and the near-infrared signal output from the intensity correction unit 22. In the following description, it is assumed that the above-described intensity correction is performed on the near-infrared signal, but this does not limit the present embodiment.

  Each of the first band-pass filter 24a and the second band-pass filter 24b includes nine frequency band band-pass filters. Each of the first band-pass filter 24a and the second band-pass filter 24b may be realized by signal processing by frequency analysis using, for example, FFT (Fast Fourier Transform). Each of the first band-pass filter 24a and the second band-pass filter 24b becomes a signal in which a pulse wave component, a body motion component, and other noise components are superimposed for each of the nine frequency bands. By using a signal for each frequency band, the arithmetic processing for reducing body motion components and other noise components from the signal is reduced, and the memory capacity and data processing time in data processing can be reduced. it can.

  The frequency band of each bandpass filter included in each of the first bandpass filter 24a and the second bandpass filter 24b is 0.5 to 1.0 Hz, 0.75 to 1.25 Hz, 1.0 to 1. 0.5 Hz, 1.25 to 1.75 Hz, 1.5 Hz to 2.0 Hz, 1.75 to 2.25 Hz, 2.0 to 2.5 Hz, 2.25 to 2.75 Hz, 2.5 to 3.0 Hz It is good to set to. The output from each bandpass filter has a waveform having only a single frequency component. The number of bandpass filters included in the first bandpass filter 24a and the second bandpass filter 24b is not limited to nine. Further, a band pass filter having a frequency band different from the above may be used.

  The control unit 26 includes a correlation coefficient calculation unit 28 and a waveform synthesis unit 30.

(Correlation coefficient calculator)
The correlation coefficient calculation unit 28 uses green for each frequency band for each signal that has passed through each of the bandpass filters of a plurality of frequency bands included in each of the first bandpass filter 24a and the second bandpass filter 24b. The correlation coefficient between the signal and the near-infrared signal and the signal intensity ratio of each signal are calculated (calculated). The correlation coefficient is related to the period time of the pulse wave waveform of the living body, and is obtained by the following formula 2 using data of the green signal and the near-infrared signal for at least two period times, for example, three seconds or more.

In Equation 2, x _i is each of green signal data, and y _i is each of near-infrared signal data. N is the number of data samples.

  The signal strength ratio is the ratio of the integrated values of the signal strength data for each frequency band, as in the above equation 1.

(Synthesizer)
The synthesizing unit 30 as the waveform synthesizing unit calculates a weighting coefficient Wn shown in the following formula 3. As is apparent from Equation 3, due to the contribution of the signal intensity ratio, in the frequency band where the intensity of the green signal is weaker than the intensity of the near-infrared signal, the intensity of the green signal after weighting described above becomes small.

  Here, “*” in Equation 3 is an operation symbol indicating multiplication.

  The waveform synthesizing unit 30 generates a weighted green signal for each frequency band by multiplying each of the green signal frequency band filter pass signals by a weighting coefficient Wn. Then, by combining the weighted green signals in the respective frequency bands, a pulse wave signal in which body motion components and other noise components are reduced is generated.

  The waveform synthesizer 30 outputs the above pulse wave signal to the pulse rate calculator 32 and the biological information display device 2.

(Pulse rate calculator)
The pulse rate calculation unit 32 as a biometric information generation unit obtains the peak interval of the pulse wave signal generated by the waveform synthesis unit 30 and obtains the pulse rate represented by the following formula 4. The pulse rate calculation unit 32 is configured to derive the pulse rate by, for example, re-sampling the pulse wave signal at 1024 Hz, and then using the pulse wave signal peak interval multiplied by, for example, three times or more and the moving average. That's fine.

  The pulse rate calculation unit 32 is not essential for the pulse wave measurement device 1, and the pulse wave measurement device 1 may not have the pulse rate calculation unit 32. In the case of such a configuration, for example, the biological information display device 2 described later may include a pulse rate calculation unit 32.

<Biological information display device>
FIG. 4 is a block diagram illustrating an example of the biological information display device 2. As shown in FIG. 4, the biological information display device 2 includes at least a signal analysis processing unit 34, a data display unit 36, and a memory unit 38. The biological information display device 2 may be mounted on the pulse wave measurement device 1.

  The signal analysis processing unit 34 is wirelessly connected or wired to the pulse wave measurement device 1, receives a pulse wave signal from the waveform synthesis unit 30 of the pulse wave measurement device 1, and receives a pulse rate from the pulse rate calculation unit 32. Receive. The signal analysis processing unit 34 may obtain the blood vessel age as the biological information data by, for example, waveform analysis using the second derivative of the pulse wave signal as analysis processing. Other examples of biometric information data include respiratory rate and stress level. The data display unit 36 may display the pulse wave signal waveform, the above-described biological information, and the like. The memory unit 38 may store a pulse wave signal, biological information, and the like that have been measured and analyzed.

<Pulse wave measurement method>
Next, referring to FIG. 5, a pulse wave measuring method for obtaining a pulse wave signal with a reduced body motion component from a signal measured by a photoelectric pulse wave method using green light and near-infrared light, and obtaining a pulse rate. explain. This method is controlled by the control unit 26 of the pulse wave measuring apparatus 1.

  First, the light emitting unit 14 irradiates a living body measurement site with a plurality of lights having different wavelengths (irradiation step) (S1).

  Next, the light receiving unit 16 receives each of the plurality of lights received through the living body and generates a plurality of signals corresponding to each light (signal generation step) (S2).

  Next, the intensity correction unit 22 corrects the intensity of the signal so as to adjust the difference between the intensity of the green signal and the intensity of the near-infrared signal to the same extent. For example, by calculating (calculating) the coefficient r of the signal intensity ratio shown in the above equation 1 based on each signal intensity in a resting state and multiplying the near-infrared signal by this coefficient r, The difference from the signal intensity of the near-infrared signal may be adjusted to the same extent. (S3).

  Next, the band-pass filters of the plurality of frequency bands of each of the first band-pass filter 24a and the second band-pass filter 24b divide each of the green signal and the near-infrared signal into a plurality of frequency components (frequency band Separation step) (S4).

  Next, the correlation coefficient calculation unit 28 uses a frequency band for each signal that has passed through each of the bandpass filters of a plurality of frequency bands included in each of the first bandpass filter 24a and the second bandpass filter 24b. Each time, the correlation coefficient between the green signal and the near-infrared signal and the signal intensity ratio of each signal are calculated (calculated) (calculation step) (S5).

  Next, the waveform synthesizer 30 multiplies each of the signals that have passed through the frequency band filter of the green signal by the weighting coefficient Wn shown in Equation 3 to generate a weighted green signal for each frequency band. Then, a weighted green signal in each frequency band is synthesized to generate a pulse wave signal with a reduced body motion component (synthesis step) (S6).

  Next, the pulse rate calculator 32 calculates the peak interval of the pulse wave signal generated in S6, and calculates the pulse rate shown in the above equation 4 (S7).

[Embodiment 2]
In the present embodiment, the measurement unit differs from the measurement unit 10 described above in that the measurement unit is configured to sandwich the living body between the light emitting unit and the light receiving unit and receive the transmitted light transmitted through the living body. Even with such a configuration, the pulse wave measuring apparatus according to the present embodiment includes the measurement unit 10, the intensity correction unit 22, the first bandpass filter 24a, and the second bandpass filter 24b described in the first embodiment. Since the control unit 26 and the pulse rate calculation unit 32 are included, more accurate biological information can be measured as compared with the conventional case.

[Embodiment 3]
A control unit (particularly an intensity correction unit, a bandpass filter, a correlation coefficient calculation unit, a waveform synthesis unit, and a pulse rate calculation unit) of the pulse wave measuring device 1 is a logic circuit (an IC chip) formed in an integrated circuit (IC chip) or the like. Hardware) or software using a CPU (Central Processing Unit).

  In the latter case, the pulse wave measuring device 1 includes a CPU that executes instructions of a program that is software that implements each function, and a ROM (Read Only Memory) in which the program and various data are recorded so as to be readable by a computer (or CPU). ) Or a storage device (these are referred to as “recording media”), a RAM (Random Access Memory) for expanding the program, and the like. And the objective of this invention is achieved when a computer (or CPU) reads the said program from the said recording medium and runs it. As the recording medium, a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, the program may be supplied to the computer via any transmission medium (such as a communication network or wireless communication) that can transmit the program. The present invention can also be realized in the form of a data signal embedded in a carrier wave in which the program is embodied by electronic transmission.

[Summary]
The pulse wave measuring apparatus 1 according to the first aspect of the present invention receives a light emitting unit 14 that irradiates a measurement site of a living body with a plurality of lights having different wavelengths, and each of the plurality of lights received through the living body. A light receiving unit 16 that generates a plurality of signals corresponding to the light of the plurality, a plurality of bandpass filters 24a and 24b that divide each of the plurality of signals into a plurality of frequency bands, and the bandpass for each of the plurality of frequency bands. A correlation coefficient calculation unit 28 that calculates correlation coefficients indicating mutual correlation of a plurality of signals that have passed through the filters 24a and 24b, and the above-described phase relationship for each signal that has passed through the plurality of bandpass filters 24a and 24b. A waveform synthesizer 30 that synthesizes the waveform of each signal after weighting according to the number is provided.

  According to the above configuration, since the signals in each frequency band are synthesized after weighting according to the correlation coefficient indicating the correlation between the plurality of signals that have passed through the bandpass filters 24a and 24b, A more accurate pulse wave can be measured.

  The pulse wave measuring apparatus 1 according to the aspect 2 of the present invention further includes an intensity correction unit 22 that corrects the intensity of the plurality of signals according to the intensity of the plurality of signals generated by the light receiving unit 16 in the aspect 1. You may have.

  According to said structure, an exact pulse wave can be measured by adjusting the difference of the intensity | strength of a signal which changes with the measurement site | parts by adjusting the intensity difference of said several signal.

  For example, when the pulse wave measuring device 1 is used for pulse wave measurement, the difference in the intensity of the plurality of signals caused by the difference in the light absorption characteristics of the blood due to the difference in the light wavelength is adjusted. A wave signal can be obtained.

  In the pulse wave measuring apparatus 1 according to aspect 3 of the present invention, in the aspect 2, the intensity correction unit 22 has a negative correlation with the intensity of the one signal with respect to one of the plurality of signals. The intensity of the one signal may be corrected by multiplying by a coefficient having

  According to the above configuration, since the signal strength of one signal is reduced, the difference between the signal strength of one signal and the signal strength of another signal can be adjusted. Thereby, a more accurate pulse wave can be measured.

  In the pulse wave measuring apparatus 1 according to the aspect 4 of the present invention, in any one of the aspects 1 to 3, the plurality of lights emitted by the light emitting unit 14 may be green light and near infrared light.

  According to said structure, a more exact pulse wave can be measured.

  The pulse wave measuring device 1 according to the fifth aspect of the present invention is the biological information generating unit (1) that generates biological information by analyzing the signal output from the waveform synthesizing unit 30 in any one of the first to fourth aspects. You may further provide the pulse rate calculating part 32).

  According to said structure, various biological information can be produced | generated from a pulse wave signal.

  The pulse wave measurement method according to the sixth aspect of the present invention receives an irradiation step S1 of irradiating a measurement site of a living body with a plurality of lights having different wavelengths, and each of the plurality of lights received through the living body, A signal generation step S2 for generating a plurality of signals corresponding to light, a frequency band separation step S4 for passing each of the plurality of signals into a plurality of frequency bands through a plurality of bandpass filters, and the plurality of frequencies For each band, a calculation step S5 for calculating a correlation coefficient indicating a correlation between the plurality of signals that have passed through the bandpass filter, and the correlation coefficient for each signal that has passed through the plurality of bandpass filters. And a synthesis step S6 for performing the synthesis after applying the corresponding weight.

  According to the above configuration, since the signals in each frequency band are synthesized after weighting according to the correlation coefficient indicating the correlation between the plurality of signals that have passed through the bandpass filters 24a and 24b, A more accurate pulse wave can be measured.

  The pulse wave measurement device according to each aspect of the present invention may be realized by a computer. In this case, the pulse wave measurement device is operated by operating the computer as each unit (software element) included in the pulse wave measurement device. The control program of the pulse wave measuring device for realizing the above in a computer and the computer-readable recording medium on which the control program is recorded also fall within the scope of the present invention.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be used for a pulse wave measuring apparatus and a pulse wave measuring method that measure a pulse wave by removing artifacts such as body motion noise generated by the movement of a living body.

DESCRIPTION OF SYMBOLS 1 Pulse wave measuring device 2 Biometric information display apparatus 10 Measuring part 12 Case 14 Light-emitting part 14a 1st light-emitting part 14b 2nd light-emitting part 16 Light-receiving part 16a 1st light-receiving part 16b 2nd light-receiving part 18 Resin mold 20 Plating 22 Strength correction unit 24a First band pass filter 24b Second band pass filter 26 Control unit 28 Correlation coefficient calculation unit 30 Synthesis unit 32 Pulse rate calculation unit 34 Analysis processing unit 36 Data display unit 38 Memory unit

Claims (5)

A light emitting unit that irradiates a biological measurement site with a plurality of light beams having different wavelengths;
A light receiving unit that receives each of the plurality of lights received through the living body and generates a plurality of signals corresponding to each light;
A plurality of bandpass filters that divide each of the plurality of signals into a plurality of frequency bands;
A correlation coefficient calculation unit that calculates a correlation coefficient indicating a correlation between a plurality of signals that have passed through the bandpass filter for each of the plurality of frequency bands;
A pulse wave measuring apparatus comprising: a waveform synthesis unit that synthesizes waveforms of each signal after weighting each signal that has passed through the plurality of bandpass filters according to the correlation coefficient.   The pulse wave measuring apparatus according to claim 1, further comprising an intensity correction unit that corrects the intensity of the plurality of signals according to the intensity of the plurality of signals generated by the light receiving unit.   The pulse wave measuring device according to claim 1, wherein the plurality of lights emitted by the light emitting unit are green light and near infrared light.   The pulse wave measurement according to any one of claims 1 to 3, further comprising a biological information generation unit that generates biological information by analyzing a signal output from the waveform synthesis unit. apparatus. An irradiation step of irradiating a biological measurement site with a plurality of light beams having different wavelengths;
A signal generating step of receiving each of the plurality of lights received through the living body and generating a plurality of signals corresponding to the respective lights;
A frequency band separation step of passing each of the plurality of bandpass filters and dividing each of the plurality of signals into a plurality of frequency bands;
A calculation step for calculating a correlation coefficient indicating a correlation between a plurality of signals that have passed through the band pass filter for each of the plurality of frequency bands;
And a synthesis step of weighting the signals that have passed through the plurality of band-pass filters according to the correlation coefficient, and then combining them.

Images