JP2003265422A - Sphygmograph device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sphygmograph device for measuring the pulse rate of an organism according to pulsus interval detected from sphygmographic waveform, capable of restraining lowering of detection accuracy due to damping of the sphygmographic waveform and holding down the influence of noise to detect the pulsus interval. <P>SOLUTION: In this sphygmograph device 1, at the time of complex- demodulating and converting the detected sphygmograph data, the central frequency of frequency of an object to be analyzed is set to the power maximum frequency (peak variable peak (n)) obtained by FFT processing in the step S140, so the frequency component corresponding to the pulsus interval can be surely extracted from the sphygmographic waveform. Three kinds of abnormality determination processing using a difference of sphygmographic interval, and each increasing and decreasing rate of pulsus interval and pulsus interval variable value are performed, and when the sphygmograph data is determined to be abnormal, the correction processing for the pulsus interval PI and pulsus interval variable value HF is performed using the sphygmograph data determined to be normal in the past. Accordingly, the detection accuracy for the pulsus interval and the pulsus interval variable value can be improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs a complex demodulation analysis on a pulse wave waveform detected from a living body in an analysis target frequency band corresponding to the analysis of the pulse rate, thereby instantaneously detecting the pulse wave waveform. The present invention relates to a pulse wave measuring device for measuring the pulse rate of a living body based on various pulse intervals.

[0002]

2. Description of the Related Art Heretofore, an electrocardiogram measuring apparatus has been known which detects a heartbeat waveform corresponding to a heartbeat of a living body and measures a heartbeat rate based on a heartbeat interval detected using the detected heartbeat waveform. . The heart rate and heartbeat interval measured by the electrocardiogram measurement device are used as information for evaluating the health condition of the living body. In addition, the electrocardiogram measurement device has a fluctuation value of the heartbeat interval (heartbeat fluctuation value) over time.
The heart rate variability value is also used as information for evaluating the health condition of the living body.

The time interval between the peaks of the heartbeat waveform is the heartbeat interval, and the heart rate can be calculated from this heartbeat interval. Further, the heartbeat interval fluctuates (changes) over time, and the fluctuation of the heartbeat interval over time is the heartbeat interval fluctuation value. The heartbeat interval is
The heart rate variability value is used for the evaluation of the autonomic nerve function because it changes due to the fluctuation (variation) of the autonomic nerve input to the sinus node.

However, in order to detect the heartbeat waveform, it is necessary to detect the pulsation of the heart existing inside the living body. Therefore, the electrocardiogram measuring device requires an electrode or the like with high accuracy that can detect the pulsation of the heart. However, since the structure is complicated and the size is large, there is a problem in that it is inferior in wearability (wearability) to a living body that performs daily activities.

On the other hand, as an alternative to the electrocardiogram measuring device, a pulse wave waveform corresponding to a wave (pulsation) of blood vessels in which blood flows in a living body is detected, and based on the pulse interval detected using the detected pulse wave waveform. A pulse wave measuring device for measuring a pulse rate has been proposed. In other words, the pulse is generated by the beating of the heart, the pulse wave waveform substantially matches the heartbeat waveform, the pulse rate measured by the pulse wave measuring device, the pulse interval, the fluctuation value of the pulse interval with the passage of time. (Pulse fluctuation value)
Indicates the values corresponding to the heart rate, the heartbeat interval, and the heartbeat fluctuation value, respectively, and can be used as information for evaluating the health condition of the living body.

Since the pulse wave waveform can be detected based on the wave (pulsation) of blood vessels that can be detected on the skin surface of the living body,
The pulse wave measuring device can detect the pulse wave waveform without using a high-precision electrode and can be downsized, so that it is superior in wearability to the living body as compared with the electrocardiogram measuring device. Become. Therefore, in evaluating the health condition, by using the pulse wave measuring device, it is possible to reduce the burden on the subject, and also in daily life, the pulse rate, the pulse interval, it is possible to measure the pulse fluctuation value, It has the advantage of being practical.

[0007]

However, the pulse wave waveform is
Since it is transmitted as a wave in the blood vessel from the heart to the pulse wave detection point and is attenuated in the blood vessel during transmission, the waveform shape becomes less clear than the heartbeat waveform, making it difficult to identify the peak. , There is a possibility that the distinction between the beats of the pulse becomes unclear. As a result, when the pulse interval is detected from the pulse wave waveform, there is a problem that the accuracy of detecting the pulse interval may decrease.

A complex demodulation analysis is known as a method for detecting the pulse interval from the pulse wave waveform. The complex demodulation analysis is an analysis method for extracting an instantaneous characteristic at the center frequency of the analysis target frequency band. Therefore, when the center frequency of the analysis target frequency band deviates from the frequency band corresponding to the pulse interval, the accuracy of detecting the pulse interval decreases.

Further, in addition to the pulsation of blood vessels, noise components generated by the movement of the living body (body movement) are likely to be superimposed on the pulse wave waveform, and the pulse wave measuring apparatus is easily affected by noise. There is. Therefore, the present invention has been made in view of these problems, in the pulse wave measuring device for measuring the pulse rate of the living body based on the pulse interval detected from the pulse wave waveform, the decrease in detection accuracy due to the attenuation of the pulse wave waveform. It is an object of the present invention to provide a pulse wave measuring device capable of suppressing the influence of noise and detecting the pulse interval.

[0010]

The invention according to claim 1 made in order to achieve such an object is a complex in a frequency band to be analyzed corresponding to the analysis of the pulse rate of a pulse wave waveform detected from a living body. A pulse wave measuring device that performs demodulation analysis to detect instantaneous pulse intervals and measures the pulse rate of a living body based on the detected pulse intervals, and performs frequency characteristic analysis on the pulse wave waveform detected from the living body. , Of the frequency characteristics of the pulse wave waveform, in the analysis target frequency band corresponding to the analysis of the pulse rate, the power maximum frequency that is the frequency with the maximum power is detected, and the center frequency of the analysis target frequency band in the complex demodulation analysis is detected. It is characterized in that the power maximum frequency is set and complex demodulation analysis is performed on the pulse waveform to detect the pulse interval.

In this pulse wave measuring device, the pulse interval detecting means detects the instantaneous pulse interval by performing complex demodulation analysis on the pulse wave waveform, and the maximum power frequency detecting means determines the frequency of the pulse wave waveform. Characteristic analysis is performed and the maximum power frequency is detected from the frequency characteristics of the detected pulse wave waveform.The center frequency setting means sets the center frequency of the analysis target frequency band in the complex demodulation analysis by the pulse interval detection means to the maximum power. It is set to the maximum frequency of the power detected by the frequency detecting means.

That is, since the maximum power frequency detected from the frequency characteristics of the pulse wave waveform represents the highest frequency among the frequency components included in the pulse wave waveform, the frequency band is approximately equal to the frequency band corresponding to the pulse interval. Become. And
Complex demodulation analysis is an analysis method for extracting the instantaneous characteristics at the center frequency of the analysis target frequency band, and sets the maximum power frequency detected by the maximum power frequency detection means to the center frequency of the analysis target frequency band. By doing so, it is possible to reliably extract the frequency component corresponding to the pulse interval from the pulse wave waveform. For this reason, it is possible to suppress a decrease in the accuracy of detecting the pulse interval when the pulse waveform is attenuated, and it is possible to suppress the influence of noise components having different frequency bands.

Further, since the pulse interval changes with the passage of time, the maximum power frequency is detected at regular intervals and the center frequency of the frequency band to be analyzed is updated, so that the center of the pulse interval changes according to the fluctuation of the pulse interval. It is possible to set the frequency to an appropriate value. Therefore, according to the pulse wave measuring device of the present invention (Claim 1), when measuring the pulse rate of a living body based on the pulse interval detected from the pulse wave waveform, a decrease in detection accuracy due to attenuation of the pulse wave waveform is suppressed, Further, it becomes possible to detect the pulse interval while suppressing the influence of noise.

As the frequency characteristic analysis method in the maximum power frequency detecting means, for example, a fast Fourier transform (FFT) can be used, and the frequency band to be analyzed in the maximum power frequency detecting means has a frequency band to be analyzed. For example, it may be set within a range of 0.5 to 3 [Hz].

Next, the pulse wave measuring device of the above (claim 1) determines that the maximum power frequency can be detected in the frequency band to be analyzed in the frequency characteristics of the pulse wave waveform, as described in claim 2. Then, the power maximum frequency detected at that time is set to the center frequency of the analysis target frequency band, and it is determined that the power maximum frequency is undetectable,
The latest normal power maximum frequency among the normal power maximum frequencies detected in the past may be set as the center frequency of the analysis target frequency band.

In this pulse wave measuring device, the first power maximum frequency detection availability determination means determines whether or not the power maximum frequency can be detected, and the center frequency setting means determines the first power. The center frequency is set based on the determination result of the maximum frequency detection availability determination means. The normal power maximum frequency is the power maximum frequency detected when the first power maximum frequency detection availability determination unit determines that the power maximum frequency is detectable.

That is, even when the maximum power frequency cannot be detected from the frequency characteristics of the pulse wave waveform, the latest normal power maximum frequency among the normal power maximum frequencies detected in the past must be set as the center frequency. Then, the center frequency of the analysis target frequency band in the complex demodulation analysis is set to a value capable of detecting the pulse interval.

Therefore, in the pulse wave measuring device of the present invention (claim 2), even when the maximum power frequency cannot be detected,
It is possible to suppress a decrease in the detection accuracy of pulse intervals, and
The influence of noise can be suppressed. Next, in the pulse wave measuring device of the above (claim 1 or claim 2), as described in claim 3, in the pulse interval detected by the pulse interval detecting means, the detection timing differs by the difference comparison time. After calculating the absolute value of the difference between the two pulse intervals as the absolute value of the pulse interval difference, it is determined that the pulse wave waveform is normal when the absolute value of the pulse interval difference is smaller than the difference normality determination reference value, and the pulse interval difference is determined. It may be determined that the pulse wave waveform is abnormal when the absolute value is equal to or larger than the difference normal determination reference value.

In this pulse wave measuring device, the pulse interval difference absolute value calculating means calculates the difference between two pulse intervals whose detection timings differ by the difference comparison time set within the time range in which the pulse wave waveform does not change abruptly. Then, the absolute value of the calculated difference is calculated as the pulse interval difference absolute value, and the first pulse wave waveform normality determination means is set to the maximum value of the pulse interval difference absolute value when the pulse wave waveform is normal. The difference normal determination reference value and the pulse interval difference absolute value are compared to determine whether the pulse wave waveform is normal or abnormal.

That is, if the pulse wave waveform is normal, the pulse interval does not change abruptly within a short time (for example, 1 [sec]). It is possible to determine whether or not the pulse wave waveform is normal based on the difference between the two pulse intervals that differ in the detection time by the difference comparison time set to. Therefore, when the pulse interval difference absolute value is smaller than the difference normal determination reference value, it can be determined that the pulse wave waveform is normal, and when the pulse interval difference absolute value is the difference normal determination reference value or more, the pulse wave It can be determined that the waveform is abnormal.

Further, as an abnormality determination coping means when it is determined that the pulse wave waveform is abnormal, for example, a determination result notifying means for notifying the user that the pulse wave waveform is in an abnormal state is provided. And good. Further, as the abnormality determination response means, the latest normal pulse wave waveform is used among the normal pulse wave waveforms that are the pulse wave waveforms detected when the pulse wave waveform is determined to be normal in the past, and the pulse wave waveform that is corrected this time is used. It is also possible to provide a wave waveform correction means. When the pulse wave waveform is determined to be abnormal, the pulse wave waveform correction means corrects the current pulse wave waveform using the latest normal pulse wave waveform, and various information calculated based on the pulse wave waveform. (Pulse interval, pulse rate, etc.)
Will be calculated as a numerical value close to the actual numerical values of various information this time.

Therefore, the pulse wave measuring device of the present invention (claim 3) can determine whether the pulse wave waveform is normal or abnormal, and even when it is determined to be abnormal. ,
By correcting the pulse wave waveform, it is possible to prevent a large error from occurring in various information (pulse interval, pulse rate, etc.) calculated based on the pulse wave waveform.

Further, in the pulse wave measuring device of the above (claim 3), as described in claim 4, the normal difference determination reference value setting means sets the value of a predetermined difference determination reference ratio to the reciprocal of the maximum power frequency. May be set as the difference normality determination reference value. That is, the reciprocal of the maximum power frequency has a value substantially equal to the pulse interval, and the absolute value of the pulse interval difference is less than or equal to a predetermined ratio to the pulse interval if the pulse wave waveform is normal. Therefore, the ratio of the maximum value of the pulse interval difference absolute value to the pulse interval when the pulse wave waveform is normal is set as the difference determination reference ratio, and the value of the difference determination reference ratio to the reciprocal of the power maximum frequency is set to the difference normal value. By setting as the determination reference value, it is possible to appropriately determine whether or not the pulse wave waveform is normal.

The difference determination reference ratio is, for example, 30
%, And an appropriate value may be set in the range of 20% to 40%. When the pulse wave measuring device of the above (Claim 4) is determined to be capable of detecting the maximum power frequency as described in Claim 5, it is the reciprocal of the maximum power frequency detected at that time. If the value of the predetermined difference determination reference ratio is set as the difference normal determination reference value and it is determined that the maximum power frequency cannot be detected, the pulse interval detection means detects it when it is determined to be detectable in the past. It is preferable to set a value of a predetermined difference determination reference ratio to the latest normal pulse interval among the normal pulse intervals that are the determined pulse intervals as the normal difference determination reference value.

In this pulse wave detection device, the second power maximum frequency detection availability determination means determines whether or not the maximum power frequency can be detected in the analysis target frequency band of the frequency characteristics of the pulse wave waveform. The difference normality determination reference value setting means sets the difference normality determination reference value based on the determination result by the second power maximum frequency detection availability determination means.

That is, even when the maximum power frequency cannot be detected from the frequency characteristic of the pulse wave waveform, the difference normality judgment reference value is obtained by using the latest normal pulse interval among the normal pulse intervals detected in the past. By setting as above, the difference normality determination reference value is set to a value that enables normality determination of the pulse wave waveform.

Therefore, the pulse wave measuring device of the present invention (claim 5) can set the difference normality judgment reference value even if the maximum power frequency cannot be detected, and whether the pulse wave waveform is normal or not. Since the determination can be performed, it is possible to prevent a large error from occurring in various information (pulse interval, pulse rate, etc.) calculated based on the pulse waveform due to the abnormality of the pulse waveform.

Next, in the pulse wave measuring device described above (any one of claims 1 to 5), as described in claim 6, the pulse interval detected by the pulse interval detecting means By performing complex demodulation analysis in the second analysis target frequency band corresponding to the analysis of parasympathetic nerve activity, the pulse interval variation value is detected from the pulse interval, and the pulse interval detected this time and the normal pulse detected in the past. The pulse interval increase / decrease rate, which represents the ratio of the interval to the latest normal pulse interval, is calculated, and the latest normal pulse interval of the pulse interval fluctuation value detected this time and the normal pulse interval fluctuation value detected in the past is calculated. A pulse interval fluctuation value increase / decrease rate that represents a ratio with the fluctuation value may be calculated. Then, the second pulse wave waveform normality determining means determines that the pulse wave waveform is normal when both the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate are increasing or decreasing. When one of the pulse interval increase / decrease rate and the pulse interval change value increase / decrease rate has an increasing tendency and the other has a decreasing tendency, it may be determined that the pulse wave waveform is abnormal.

In this pulse wave measuring device, the third power maximum frequency detection availability determination means determines whether the power maximum frequency can be detected in the analysis target frequency band of the frequency characteristics of the pulse wave waveform. The determination is made, and the pulse interval variation value detecting means detects the pulse interval variation value from the pulse interval. Further, the pulse interval increase / decrease rate calculating means uses the latest pulse interval detected this time by the pulse interval detecting means and the pulse interval detected by the pulse interval detecting means when it is determined that the maximum power frequency can be detected in the past. A pulse interval increase / decrease rate that represents a ratio of a certain normal pulse interval to the latest normal pulse interval is calculated. Furthermore, the pulse interval variation value increase / decrease rate calculation means calculates the latest pulse interval variation value detected by the pulse interval variation value detection means this time and the pulse interval variation value when it is determined that the maximum power frequency can be detected in the past. A pulse interval variation value increase / decrease rate that represents a ratio of the normal pulse interval variation value, which is the pulse interval variation value detected by the detection means, to the latest normal pulse interval variation value is calculated.

In other words, if the pulse wave waveform is normal, the change rates of the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate become substantially equal, and both are in the same direction (either the increasing trend or the decreasing trend). Direction). From this, it is possible to determine whether or not the pulse wave waveform is normal based on the respective changing directions of the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate.

As means for responding to abnormality determination when it is determined that the pulse wave waveform is abnormal, for example, a determination result notifying means or a pulse wave waveform correcting means may be provided, and the pulse wave waveform is determined to be abnormal. In this case, by correcting the current pulse wave waveform by the pulse wave waveform correction means, various information calculated based on the pulse wave waveform (pulse interval, pulse rate, etc.) is the numerical value of the actual various information of this time. It will be calculated as a value close to.

Therefore, the pulse wave measuring device of the present invention (claim 6) can determine whether the pulse wave waveform is normal or abnormal, and even when it is determined to be abnormal. ,
It is possible to suppress the occurrence of a large error in various information (pulse interval, pulse rate, etc.) calculated based on the pulse wave waveform.

In the pulse wave measuring device of the above (claim 6), as described in claim 7, both the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate tend to increase or decrease. In this case, the change rate absolute value is the first
It is good to judge that the pulse wave waveform is normal when it is less than the increase / decrease rate judgment reference value, and to judge that the pulse wave waveform is abnormal when the increase / decrease rate difference absolute value is not less than the first increase / decrease rate judgment reference value. .

Note that the increase / decrease rate difference absolute value is the absolute value of the difference between the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate, and the first increase / decrease rate determination reference value is the value when the pulse wave waveform is normal. It is set to the maximum absolute value of the change rate difference. That is, even if both the pulse interval increase / decrease rate and the pulse interval change value increase / decrease rate change in the same direction, if there is a large difference between the pulse interval increase / decrease rate and the pulse interval change value increase / decrease rate,
It can be determined that the changing tendencies are different. for that reason,
When the increase / decrease rate difference absolute value is large (specifically, when the increase / decrease rate difference absolute value is greater than or equal to the first increase / decrease rate determination reference value), changes in the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate are changed. It is determined that the tendency is different, and the pulse wave waveform is determined to be abnormal.

Further, in the pulse wave measuring device of the above (claim 6 or claim 7), as described in claim 8, one of the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate is increasing. If the increase / decrease difference absolute value is less than the second increase / decrease rate determination reference value when the other is decreasing, it is determined that the pulse wave waveform is normal, and the increase / decrease rate difference absolute value is the second increase / decrease rate determination. When it is equal to or more than the reference value, it may be determined that the pulse wave waveform is abnormal.

The absolute value of the increase / decrease rate difference is the absolute value of the difference between the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate, and the second increase / decrease rate determination reference value is used when the pulse wave waveform is normal. It is set to the maximum possible absolute value of the increase / decrease rate difference. That is, even when the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate change in different directions, if the difference between the pulse interval variation rate and the pulse interval variation value increase / decrease rate is small,
It can be determined that the change tendencies are substantially equal. Therefore, when the increase / decrease rate difference absolute value is small (specifically, when the increase / decrease rate difference absolute value is less than the second increase / decrease rate determination reference value)
First, it is determined that the respective change tendencies are substantially equal, and it is determined that the pulse wave waveform is normal.

Therefore, the pulse wave measuring device of the present invention (claims 7 and 8) determines whether the pulse wave waveform is normal or abnormal based on the pulse interval increase / decrease rate and the pulse interval change value increase / decrease rate. In doing so, the determination accuracy can be improved. Next, the pulse wave measuring device described above (any one of claims 1 to 8) uses an autocorrelation function to calculate an autocorrelation coefficient for a time interval of a pulse wave waveform, as described in claim 9. After the calculation, the central peak appearing in the center of the autocorrelation coefficient and the first peak that appears next to the central peak
A peak and a central peak coefficient value representing the autocorrelation coefficient of each of the central peak and the first peak;
It is preferable to detect the peak coefficient value and detect the first peak time interval representing the time interval between the central peak and the first peak. Then, the third pulse wave normality determining means determines the pulse wave based on the result of comparison between the pulse interval detected by the pulse interval detecting means and the first peak time interval detected by the peak coefficient time interval detecting means. It is determined whether the waveform is normal.

In this pulse wave measuring device, the autocorrelation coefficient calculating means calculates the autocorrelation coefficient concerning the time interval of the pulse wave waveform, and the peak coefficient time interval detecting means calculates the central peak coefficient value, The first peak coefficient value and the first peak time interval are detected. That is, since the peak of the autocorrelation coefficient of the pulse wave waveform calculated using the autocorrelation function appears according to the frequency characteristics of the pulse wave waveform, the time interval between the central peak and the first peak is The value is approximately equal to the actual pulse interval. From this, whether or not the pulse wave waveform is normal is determined based on the result of comparison between the pulse interval detected by the pulse interval detection means and the first peak time interval detected by the peak coefficient time interval detection means. Can be determined.

Further, as means for dealing with abnormality when it is determined that the pulse waveform is abnormal, for example, a determination result notifying means or a pulse waveform correcting means may be provided, and the pulse waveform is determined to be abnormal. In this case, by correcting the current pulse wave waveform by the pulse wave waveform correction means, various information calculated based on the pulse wave waveform (pulse interval, pulse rate, etc.) is the numerical value of the actual various information of this time. It will be calculated as a value close to.

Therefore, the pulse wave measuring device of the present invention (claim 9) can determine whether the pulse wave waveform is normal or abnormal, and even when it is determined to be abnormal. ,
It is possible to suppress the occurrence of a large error in various information (pulse interval, pulse rate, etc.) calculated based on the pulse wave waveform.

In the pulse wave measuring device of the above (claim 9), as described in claim 10, the third pulse wave waveform normality judging means detects the pulse interval detected by the pulse interval detecting means.
A case where it is larger than a time interval minimum value obtained by subtracting the pulse wave waveform sampling period from the first peak time interval and smaller than a time interval maximum value obtained by adding the pulse wave waveform sampling period to the first peak time interval; Further, when the first peak coefficient value is larger than the predetermined peak coefficient determination reference value, it may be determined that the pulse wave waveform is normal.

Since the pulse wave waveform cannot extract the waveform fluctuation in a time shorter than the sampling cycle, there is a possibility that an error corresponding to the sampling cycle occurs in the advance direction or the delay direction on the time axis. Therefore, the time interval minimum value is set to a value obtained by subtracting the pulse wave waveform sampling period from the first peak time interval, and the time interval maximum value is set to the first time interval.
A value obtained by adding the sampling period of the pulse wave waveform to the peak time interval is set.

In the calculated waveform of the autocorrelation coefficient, the autocorrelation coefficient of the true first peak takes a value of a predetermined ratio (for example, 90%) or more to the autocorrelation coefficient of the central peak. Therefore, by using the peak coefficient determination reference value set for determining the authentic first peak according to the predetermined ratio, the first peak detected in the waveform of the calculated autocorrelation coefficient is authentic. Can be determined.

This means that the pulse interval detected by the pulse interval detecting means is larger than the minimum value of the time interval and smaller than the maximum value of the time interval.
When the peak coefficient value is larger than the peak coefficient determination reference value, it can be determined that the pulse wave waveform is normal.

Therefore, the pulse wave measuring apparatus of the present invention (claim 10) improves the determination accuracy in determining whether the pulse wave waveform is normal or abnormal based on the autocorrelation coefficient of the pulse wave waveform. Can be made. Further, the pulse wave measuring device according to the above (claim 9 or claim 10) has, as described in claim 11, at least one or more peaks sequentially appearing after the first peak in addition to the central peak and the first peak. And a peak coefficient value that represents the autocorrelation coefficient of each of the detected peaks, and a peak time interval that represents the time interval between adjacent peaks of each of the detected peaks. It may be determined whether or not the pulse wave waveform is normal based on the comparison result of the pulse intervals detected in 1. and all the peak time intervals.

In this pulse measuring device, the peak coefficient time interval detecting means detects all the peak coefficient values and the peak time intervals, and the third pulse wave normality judging means detects the pulse interval and all the pulse intervals. Based on the comparison result with the peak time interval, it is determined whether or not the pulse wave waveform is normal.

In other words, the peak coefficient time interval detecting means detects the central peak and the n peaks that sequentially appear after the central peak, and the self-phase relationship of the nth peak for each of the detected n peaks. The nth peak coefficient value representing the number is detected, and the first peak time interval representing the time interval between the central peak and the first peak, the (n-1) th peak and the nth peak.
The nth peak time interval, which represents the time interval with the peak, is detected. Further, the third pulse wave waveform normality determining means determines whether or not the pulse wave waveform is normal based on all comparison results of the pulse intervals detected by the pulse interval detecting means and the n peak time intervals. To determine. Note that n is an integer of 2 or more.

That is, the normality determination of the pulse wave waveform is not made based on one peak time interval, but the normality determination of the pulse wave waveform is made based on a plurality of peak time intervals.
In addition, regarding the plurality of peaks appearing in the waveform of the autocorrelation coefficient of the pulse wave waveform, the time intervals of the respective peaks are values substantially equal to the actual pulse intervals of the living body, and thus are not limited to the first peak time intervals. The other peak time intervals can also be used for determining the normality of the pulse wave waveform. Further, compared to the case where the normal determination of the pulse wave waveform is performed based on one peak time interval, the number of comparisons is increased in the case of using a plurality of peak time intervals, which enables more accurate determination. Become.

Therefore, the pulse wave measuring apparatus of the present invention (claim 11) improves the determination accuracy in determining whether the pulse wave waveform is normal or abnormal based on the autocorrelation coefficient of the pulse wave waveform. Can be made. The third pulse wave normality determining unit may detect the pulse interval detected by the pulse interval detecting unit for each of the n peaks by the peak coefficient time interval detecting unit. The sampling cycle of the pulse wave waveform is set to the n-th peak time interval which is larger than the minimum value of the time interval obtained by subtracting the sampling cycle of the pulse wave waveform from the peak time interval and which is detected by the peak coefficient time interval detecting means. It is determined that the pulse wave waveform is normal when the sum is smaller than the maximum value of the time interval and all the n-th peak coefficient values are larger than a predetermined peak coefficient determination reference value. Can be configured.

The pulse wave measuring device of the above (Claim 2, Claim 5 and Claim 7) comprising the first, second and third power maximum frequency detection propriety judging means is, for example, Claim 12.
As described in each power maximum frequency detection feasibility determination means, in the analysis target frequency band of the frequency characteristics of the pulse wave waveform, in addition to the maximum peak which becomes the power maximum value, a predetermined quasi-peak determination for the power maximum value. When it is determined that there is no quasi-peak having a power equal to or higher than the reference ratio, it may be configured to determine that the maximum power frequency can be detected. The quasi-peak judgment standard ratio is
In the frequency characteristics of the pulse waveform, the frequency corresponding to the pulse interval is set to a value that can be identified, for example, 50%.
Can be set to.

That is, when there is no large peak other than the maximum power value, the frequency at which the maximum power value is reached is
Since it can be determined that the maximum power frequency is substantially equal to the frequency band corresponding to the pulse interval, it can be determined that the maximum power frequency can be detected. In addition, in the case where it is determined that there is a quasi-peak other than the maximum peak in the frequency band to be analyzed of the frequency characteristics of the pulse wave waveform, the frequency of the quasi-peak and the maximum power frequency are allowed as the same frequency. When determining that the maximum power frequency is included, it is preferable to determine that the maximum power frequency can be detected.

That is, when the maximum peak and the quasi-peak are distributed in the allowable frequency range, the pulse interval can be detected at the center frequency of the analysis target frequency band in the complex demodulation analysis regardless of which frequency is used. Can be set to a value. Therefore, it can be determined that the maximum power frequency can be detected.

Furthermore, in the case where it is determined that there is a quasi-peak other than the maximum peak in the frequency band to be analyzed of the frequency characteristics of the pulse wave waveform, the quasi-peak frequency and the power maximum frequency are allowed as the same frequency. When it is determined that the maximum power frequency is not included in the allowable frequency range, it is determined that the maximum power frequency cannot be detected.

That is, when the maximum peak and the quasi-peak are not within the allowable frequency range, it is not possible to determine which frequency is close to the frequency band corresponding to the pulse interval, so the power maximum frequency cannot be detected. Can be determined. Therefore, the pulse wave measuring device of the present invention (claim 12),
It is possible to properly judge whether the maximum power frequency can be detected or not, prevent the center frequency from being set to an inappropriate value, and also due to the abnormal pulse wave waveform. It is possible to prevent a large error from occurring in various information (pulse interval, pulse rate, etc.) calculated based on the pulse wave waveform.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments to which the present invention is applied will be described below with reference to the drawings. Needless to say, the embodiment of the present invention is not limited to the following embodiments, and various forms can be adopted as long as they are within the technical scope of the present invention.

First, as an embodiment, FIG. 1A shows a schematic configuration diagram of a pulse wave measuring apparatus 1 for measuring a pulse wave of a human body and performing an analysis process. The pulse wave measuring device 1 is a pulse wave sensor 11 that is attached to a human body and outputs a detection signal according to a pulse wave.
Based on the detection signal output from the pulse wave sensor 11,
While detecting the pulse wave waveform, the pulse interval from the pulse wave waveform,
Data processing device 19 for calculating pulse rate and pulse interval fluctuation value
And is configured. Further, the pulse wave measuring device 1
It has a shape that can be worn on the human body, for example,
It is shaped like a wristwatch.

The pulse wave sensor 11 includes the light emitting element 1
3, a light receiving element 15 and a drive circuit 17 for the light emitting element 13, and is a known optical reflection type sensor. Here, FIG. 1B is an explanatory view schematically showing a cross-sectional state when the pulse wave sensor 11 is attached to the human body 101. Note that, in FIG. 1B, the human body 101 is shown as a cross-sectional view, and a plurality of blood vessels 102 (for example, capillaries) are present inside the human body 101.

Then, as schematically shown in FIG. 1A, when light is emitted from the light emitting element 13 toward the human body, part of the light hits the blood vessel 102 passing through the inside of the human body,
The remaining light is absorbed by hemoglobin in the blood flowing inside the blood vessel 102, is reflected by the blood vessel 102 and is scattered, and a part of the light reaches the light receiving element 15. At this time, the amount of hemoglobin existing in the portion of the blood vessel 102 that is irradiated with light is
Since the amount of light absorbed by hemoglobin also changes in a wave-like manner due to the pulsation of blood, the amount of light reflected by the blood vessel 102 and detected by the light-receiving element 15 becomes a pulsation of blood. It changes accordingly.

That is, the pulse wave sensor 11 outputs the electric signal generated by the light receiving element 15 according to the change in the amount of received light to the data processing device 19 as a detection signal which becomes pulse wave information. Further, the data processing device 19 includes the detection circuit 2
1, an AD converter 23 (ADC), and a microcomputer 25.

The detection circuit 21 amplifies the detection signal (electrical signal) from the pulse wave sensor 11 and outputs it to the AD converter 23. The AD converter 23 converts the analog signal input from the detection circuit 21 into a digital signal, and outputs the converted digital signal to the microcomputer 25.

The microcomputer 25 incorporates an algorithm for detecting a pulse wave waveform based on the detection signal output from the pulse wave sensor 11 and performing various kinds of analysis processing on the pulse wave waveform. Then, by performing various analysis processes, the pulse interval, the pulse rate, and the pulse interval variation value are calculated from the pulse wave waveform.

Next, the pulse wave waveform analysis processing executed by the microcomputer 25 will be described. Note that FIG.
A flowchart showing the processing contents of the pulse wave waveform analysis processing is shown in FIG. When the pulse waveform analysis process is started, first, S
At 110, initial setting processing for initializing various parameters is executed. In the initial setting process, 1 is assigned to the data storage number counter n, and the initial normality determination flag a is reset (0 is assigned).

In the next step S120, sampling processing for storing the detection signal from the pulse wave sensor 11 as pulse wave data is performed. In this embodiment, the sampling cycle is 20 [H
z] is set. In the next S130, it is determined whether or not the amount of pulse wave data corresponding to one detection section has been stored. If the determination is affirmative, the process proceeds to S140, and if the determination is negative, the process returns to S120. Transition. That is,
Until the amount of pulse wave data required for one process is stored, the process of S120 and S130 is repeatedly executed to continue the pulse wave data storage process.

Here, FIG. 7 is an explanatory view schematically showing the detection section of the pulse wave data. The amount of pulse wave data included in one detection section is pulse wave data for 60 [sec] (1200 pieces because the sampling cycle is 20 [Hz]). In FIG. 7, the detection section of 60 [sec] is included. (Detection segment) is shown as data1, data2, and data3. Then, the adjacent detection interval is 30 [se
c] are set to overlap each other. In addition, data1
In the detection section of, the first half corresponds to before the processing start time, and since there is no detection signal from the pulse wave sensor 11, a sine wave set to a cycle approximately equal to a general pulse interval is generated. It is added as virtual data (data1 '). In addition, the data (ou
tdata) represents data used in an autocorrelation calculation process described later.

Returning to the flowchart of FIG. 2, the amount of pulse wave data corresponding to one detection section is stored (S130).
If the affirmative decision is made in step S), and the process proceeds to step S140, step S140
Then, the frequency characteristic analysis by fast Fourier transform (FFT) is performed on one pulse wave data. In particular,
FFT processing is performed using 512 pulse wave data existing in the central portion of the detection section, and the frequency characteristic of the pulse wave data (pulse wave waveform) is detected. Then, in the detected frequency characteristic, the power has the maximum value in the section of 0.5 [Hz] to 3 [Hz] (corresponding to 30 to 180 [times / minute] in pulse rate) that is the analysis target section. The maximum peak is detected, and the frequency at the maximum power value of the frequency characteristic is detected as the maximum power frequency. Then, the value of the detected maximum power frequency is substituted into the peak variable peak (n). The peak variable peak (n) is used as a variable representing the power maximum frequency in the nth detection section.

Further, in S140, a process for judging whether or not a normal power maximum frequency corresponding to an actual pulse interval can be detected from the pulse wave data (pulse wave waveform) in the current detection section is performed. There is. That is, in S140, it is determined whether or not there is a quasi-peak having a power equal to or higher than the quasi-peak determination reference ratio (50%) with respect to the maximum power value in the analysis target section. Determines that the normal maximum power frequency corresponding to the actual pulse interval can be detected from the current pulse wave data (pulse wave waveform). Further, when it is determined that the quasi-peak exists, whether or not the frequency of the quasi-peak and the power maximum frequency are included in the allowable frequency range (for example, 0.039 [Hz]) allowed as the same frequency. If it is determined that the quasi-peak frequency and the maximum power frequency are within the allowable frequency range, it is determined that the normal maximum power frequency can be detected. Further, when it is determined that the quasi-peak frequency and the power maximum frequency are not included in the allowable frequency range, it is determined that the normal power maximum frequency cannot be detected.

There may be a plurality of quasi-peaks as well as a single quasi-peak. When a plurality of quasi-peaks are present, the maximum power frequency can be detected when all the quasi-peaks are included in the allowable frequency range. If any one of them is not included in the allowable frequency range, it is determined that the maximum power frequency cannot be detected. Further, the allowable frequency range may be set to be, for example, a range of 5% or less with respect to the frequency band to be analyzed.

That is, in S140, the maximum power frequency in the frequency characteristic of the pulse wave data is detected, the detected value is substituted into the peak variable peak (n), and the normal power is obtained from the pulse wave data in the current detection section. A process of determining whether or not the maximum frequency can be detected (in other words, a process of determining whether or not the power maximum frequency detected this time is a normal value) is performed.

In subsequent S150, the normal maximum power frequency (peak variable peak) in the processing in S140 is obtained.
(N)) is determined to be detectable, and if it is determined that the maximum power frequency is detectable (affirmative determination), the process proceeds to S190, and the maximum power frequency is detected. If it is determined to be impossible (negative determination), the process proceeds to S160.

When a negative determination is made in S150 and the process proceeds to S160, it is determined in S160 whether or not the initial normality determination flag a is in the set state (a ≠ 0). If an affirmative determination is made, the process proceeds to S180. , If the determination is negative, S170
Move to. When a negative determination is made in S160 and the process proceeds to S170, an increment process (n = n + 1) for adding 1 to the data storage number counter n is performed in S170. S1
When the process in 70 ends, the process proceeds to S120 again, and the pulse wave data storage process (sampling process) in the next detection section is started.

That is, in the processing of S140, it is determined from the detection of the frequency characteristics of the pulse wave data (pulse wave waveform) that the maximum power frequency cannot be detected, and the initial normality determination flag a is in the reset state (a = 0). While S120,
The steps S130, S140, S150, S160 and S170 are repeatedly executed.

When an affirmative decision is made in S150 and the flow shifts to S190, in S190, the value of the peak variable peak (n) detected in S140 is used as the center frequency variable f of the analysis target frequency band in the complex demodulation analysis in S310 described later.
Set to c (n). In addition, a negative determination is made in S150,
Further, when an affirmative determination is made in S160 and the process proceeds to S180, in S180, the maximum normal power which is the power maximum frequency (peak variable peak (n)) detected when the normal value is previously determined to be detectable in S140. The value of the latest normal power maximum frequency (normal peak variable peak (m)) of the frequencies (normal peak variable peak (m)) is set as the center frequency variable fc (n) of the analysis target frequency band.

When the process of S180 or S190 is completed, the process proceeds to S200, and the complex demodulation analysis execution process is performed in S200. FIG. 3 shows a flowchart showing the processing contents of the complex demodulation analysis execution processing executed in S200. When the complex demodulation analysis execution process is started, first, in S310, a complex demodulation analysis is performed on the pulse wave data stored in S120, and a process of calculating an instantaneous pulse interval of the pulse wave data is performed. The complex demodulation analysis is a non-linear time series analysis in the time domain for analyzing unstable vibration, and the analysis is performed in the following four steps.

(1) The analysis target frequency band to be analyzed is set, and the region is frequency-shifted to 0 [Hz]. That is, the data is multiplied by the complex sin function having the center frequency of the analysis target frequency band. (2) From the obtained complex signal, a low-pass filter is used to extract only the component of the analysis target frequency band.

(3) The real part and imaginary part of the above component are converted into a polar coordinate system, and the amplitude of vibration and the phase of vibration are obtained as a function of time. (4) By differentiating the phase signal, the frequency of 0 [H
The time function of the deviation from z] is obtained. By adding the center frequency in (1) to this function, the instantaneous frequency is obtained as a function of time.

By performing the complex demodulation analysis of the pulse wave data according to the above procedure, the instantaneous frequency of the pulse wave data can be calculated, and the instantaneous pulse interval can be calculated by calculating the reciprocal of the calculated instantaneous frequency. . In S310,
The center frequency of the analysis target frequency band in the complex demodulation analysis of the pulse wave data is set to the center frequency variable fc (n) set in the process of S190 or S180, the filter order is set to 100, and the analysis target frequency is set. The band (cutoff frequency) is set in the range of (fc ± (fc / 2)), and complex demodulation analysis is executed. Then, in S310,
For the pulse wave data in the detection section of 60 [sec], 1200 instantaneous frequency data are calculated by performing complex demodulation analysis under the above conditions (center frequency, filter order, analysis target frequency), and the reciprocal thereof is calculated. 1200
The individual pulse interval data is calculated.

In the next S320, 1 calculated in S310
An average value of 200 pulse interval data (reciprocal of instantaneous frequency) for every 20 pulses is calculated in time series, and 60 for every 1 [sec] is calculated.
The individual pulse interval pi is calculated. In the following S330, S3
From the 60 pulse intervals pi calculated in 20, the data (outda) for 30 [sec] in the central portion of the detection section
30 pulse intervals pi corresponding to ta) are extracted. Then, the average value of the 30 pulse intervals pi is calculated as the average pulse interval P
Calculate as I (n). The average pulse interval PI
(N) represents the average value of the pulse interval pi in the nth detection section.

In the next step S340, abnormality determination processing using the difference in pulse intervals is performed. FIG. 4 shows a flowchart showing the processing contents of the “abnormality determination processing using the difference in pulse intervals” executed in S340. When the "abnormality determination process using the difference between pulse intervals" is started, in S410, S33 is performed.
For 30 pulse intervals pi extracted by 0, the difference between adjacent pulse intervals pi is calculated when arranged in time series, and the pulse interval difference absolute value pid (x) is the absolute value of each of the 29 differences. To calculate.

At S420, which is the same as S150, S
It is determined whether or not it is determined that the normal maximum power frequency can be detected in the FFT processing at 140.
Determined that the maximum power frequency can be detected (affirmative determination)
If it is determined that the maximum power frequency cannot be detected (negative determination), the process proceeds to S440.
Move to 430.

When a negative determination is made in S420 and the process proceeds to S430, in S430, a normal average pulse interval PI (m) which is the average pulse interval PI (n) detected in S310 when it was previously determined that peak detection is possible in S140. Value of a predetermined difference determination reference ratio (0.3 in this embodiment) with respect to the latest normal average pulse interval PI (m), is set as a difference normal determination reference value J (also referred to as an abnormality determination threshold J).

When an affirmative determination is made in S420 and the process proceeds to S440, in S440, for the pulse wave data of the current detection section, a predetermined difference determination reference ratio ((reverse number) of the maximum power frequency (peak variable peak) detected in S140 ( In this embodiment, the value of 0.3) is set as the difference normality determination reference value J (also referred to as abnormality determination threshold value J).

When the processing in S430 or S440 is completed, the process proceeds to S450, in which 1 is substituted into the counter variable x (x = 1) to initialize the counter variable x. In subsequent S460, the pulse interval difference absolute value pid (x) corresponding to the counter variable x is the difference normal determination reference value J.
It is determined whether or not it is smaller, and if a positive determination is made, S
If the determination is negative, the process proceeds to S480.

When an affirmative determination is made in S460 and the process proceeds to S470, it is determined in S470 that the pulse wave data (pulse wave waveform) in the current detection section is a normal pulse wave waveform.
When a negative determination is made in S460 and the process proceeds to S480, S4
In 80, it is determined that the pulse wave data (pulse wave waveform) in the current detection section is an abnormal pulse wave waveform, and in the subsequent S490, the waveform abnormality determination flag Fm is set to the set state,
Record that the current pulse wave data is abnormal. In addition,
The waveform abnormality determination flag Fm is set to the reset state and initialized each time the processing in S120 is started. When the pulse wave data is abnormal, the waveform abnormality determination flag Fm is set to the set state and the pulse wave data is If it is normal, it is set to the reset state.

When the processing in S470 or S490 is completed, the process proceeds to S500, and in S500, the counter variable x
Is determined to be 29, and if an affirmative determination is made, the "abnormality determination process using the difference in pulse intervals" ends, the process shifts to the complex demodulation analysis execution process again, and a negative determination is made. Then, the process proceeds to S510.

When a negative determination is made in S500 and the process proceeds to S510, in S510, an increment process (X = X + 1) for adding 1 to the counter variable x is executed. S510
When the process in 1 is completed, the process proceeds to S460 again. That is, during the period when the counter variable x is 29 or less, S46.
The processing from 0 to S510 is repeatedly executed, and when at least one of the pulse interval difference absolute values pid (x) is the difference normal determination reference value J or more, it is determined that the current pulse wave data is abnormal. And record that it is abnormal.

In the "abnormality determination process using the difference between pulse intervals" constituted by the above processing contents, the absolute value of pulse interval difference pid (x) is calculated from the pulse interval pi at intervals of 1 [sec], and in S140 The difference normal determination reference value J is set according to the determination result of whether or not the power maximum frequency can be detected, and based on the comparison result between the pulse interval difference absolute value pid (x) and the difference normal determination reference value J, in the current detection section. A process of determining whether or not the pulse wave data (pulse wave waveform) is normal is performed.

FIG. 8 shows a waveform example of the pulse wave data, the pulse interval pi, and the pulse interval difference absolute value pid. In addition,
The waveform shown in FIG. 8 is the pulse interval pi, the pulse wave data, and the pulse interval difference absolute value pid in order from the top. In the area represented as the "abnormality determination section" in FIG. 8, the value of the pulse interval difference absolute value pid fluctuates sharply, and the pulse wave data is in an abnormal state due to the influence of noise such as body movement. I understand. In such a case, the pulse interval difference absolute value p
Since id (x) exceeds the difference normal determination reference value J, the pulse wave data is determined to be in an abnormal state in the "abnormality determination process using the difference in pulse intervals".

"Abnormality determination process using difference in pulse interval"
When the process in (3) is completed and the process proceeds to the complex demodulation analysis execution process, the subsequent S350 is executed. In S350, S31
For the pulse interval data calculated with 0, the second analysis target frequency band as the analysis target frequency band is set to 0.15 [H
z] to 0.45 [Hz], the filter order is 10, and complex demodulation analysis is performed to calculate 1200 pulse interval variation value data.

The analysis target frequency band used for the complex demodulation analysis in S350 corresponds to the second analysis target frequency band described in the claims, and the frequency corresponding to the analysis of the parasympathetic nerve activity of the living body. Set to band. In the next step S360, the average value of every 20 pulse interval variation values calculated in S350 is calculated in time series, and 60 pulse interval variation values hf are calculated every 1 [sec].

In the following S370, 6 calculated in S360 is calculated.
From the 0 pulse interval variation values hf, 30 pulse interval variation values hf corresponding to data (outdata) for 30 [sec] in the central portion of the detection section are extracted. Then, the average value of the 30 pulse interval variation values hf is calculated as the average pulse interval variation value HF (n).

In the next step S380, an abnormality determination process is performed using each increase / decrease rate of the pulse interval and the pulse interval variation value. Figure 5
FIG. 10 is a flowchart showing the processing contents of the “abnormality determination processing using each increase / decrease rate of pulse interval and pulse interval variation value” executed in S380. When the "abnormality determination process using each increase / decrease rate of pulse interval and pulse interval variation value" is started, in S610, an increase / decrease rate of the average pulse interval PI and an increase / decrease rate of the average pulse interval variation value HF are calculated. I do. Specifically, the latest average pulse interval PI (n) detected in S330 this time and the average pulse interval PI detected in S330 when the maximum power frequency is determined to be detectable in S140 in the past. A certain normal pulse interval PI
A process of calculating a pulse interval increase / decrease rate PI (n) / PI (m) that represents a ratio with the latest normal pulse interval PI (m) in (m) is performed. Further, the latest average pulse interval variation value HF (n) detected in S370 of this time and S37 when the maximum power frequency can be detected in S140 in the past.
The pulse interval fluctuation value increase / decrease rate HF that represents the ratio of the latest normal pulse interval fluctuation value HF (m) among the normal pulse interval fluctuation value HF (m) that is the average pulse interval fluctuation value HF detected at 0.
A process of calculating (n) / HF (m) is performed.

At the next step S620, the "pulse rate increase / decrease rate PI
(N) / PI (m) is 1 or more and the pulse interval variation value increase / decrease rate HF (n) / HF (m) is 1 or more "(hereinafter referred to as increasing tendency condition C1), or" pulse Whether the interval increase / decrease rate PI (n) / PI (m) is less than 1 and the pulse interval variation value increase / decrease rate HF (n) / HF (m) is less than 1 "(hereinafter, decrease tendency condition C2) I'm making a decision. Then, the increasing tendency condition C1 or the decreasing tendency condition C2
If at least one of the above conditions is satisfied, an affirmative decision is made and the operation proceeds to S640, and if both conditions of the increasing tendency condition C1 and the decreasing tendency condition C2 are not satisfied, a negative decision is made and the operation proceeds to S630.

If an affirmative decision is made in S620 and the operation proceeds to S640, then in S640, the pulse interval increase / decrease rate PI (n) / P.
I (m) and pulse interval fluctuation value increase / decrease rate HF (n) / HF
If the absolute value of the difference from (m) (absolute rate difference absolute value) is less than the first increase / decrease rate determination reference value (0.6 in this embodiment), and an affirmative determination is made. If so, the process proceeds to S660, and if a negative determination is made, the process proceeds to S650.

When a negative determination is made in S620 and the process proceeds to S630, in S630, the pulse interval increase / decrease rate PI (n) / P.
I (m) and pulse interval fluctuation value increase / decrease rate HF (n) / HF
When the absolute value of the difference from (m) (absolute rate difference absolute value) is less than the second increase / decrease rate determination reference value (0.2 in this embodiment), and an affirmative determination is made. If so, the process proceeds to S660, and if a negative determination is made, the process proceeds to S650.

In S650, it is determined that the pulse wave data (pulse wave waveform) in the current detection section is abnormal, and the waveform abnormality determination flag Fm is set to the set state, so that the current pulse wave data is abnormal. Record that. In addition, S66
In 0, it is determined that the pulse wave data (pulse wave waveform) in the current detection section is a normal pulse wave waveform.

When the process of S650 or S660 is completed, the "abnormality determination process using each increase / decrease rate of the pulse interval and the pulse interval variation value" ends, and the process shifts to the complex demodulation analysis execution process again. The “abnormality determination process using each increase / decrease rate of the pulse interval and the pulse interval variation value” configured by the above processing contents is the pulse interval increase / decrease rate PI (n) / PI (m) and the pulse interval variation value increase / decrease rate HF. (N) / HF (m) change tendency in the same direction, pulse interval increase / decrease rate PI (n) / PI (m) and pulse interval change value increase / decrease rate HF (n) / HF Based on the comparison result between the absolute value of the difference from (m) and the increase / decrease rate determination reference value, it is determined whether or not the pulse wave data in the current detection section is normal.

When the "abnormality determination process using each increase / decrease rate of the pulse interval and the pulse interval variation value" is completed and the process goes to the complex demodulation analysis execution process again, the process in S380 is completed and the complex demodulation analysis is executed. The process ends. When the complex demodulation analysis execution process ends and the process returns to the pulse wave waveform analysis process, the subsequent S210 is executed. In S210, "abnormality determination processing using an autocorrelation function" is performed. In FIG. 6, S2
10 is a flowchart showing the processing contents of “abnormality determination processing using autocorrelation function” executed in 10.

When the "abnormality determination process using the autocorrelation function" is started, in S710, the pulse wave data in the current detection section is set to 10 [s] without overlap (Overlap).
ec] is divided into 6 segments, and 200 segment data included in each segment are extracted.

At the next S720, 6 extracted at S710
For each segment data in the segment of the section, the autocorrelation coefficient is calculated using the autocorrelation function shown in [Equation 1].

[0100]

[Equation 1] In [Equation 1], x (t) is pulse wave data, and τ is set to satisfy T = 200 · τ.

FIG. 9 shows an example of the waveform of the autocorrelation coefficient calculated in S720. As shown in FIG. 9, in the waveform of the autocorrelation coefficient, the autocorrelation coefficient value of the central peak at the time difference τ = 0 becomes the maximum value, and as it moves in the horizontal axis (time difference) direction from the central peak, it is quasi-periodically quasi-linear The shape in which a peak appears is shown. In FIG. 9, in addition to the central peak at time difference τ = 0, first, second, and third quasi-peaks appear at time differences τ1, τ2, and τ3, respectively, and the autocorrelation coefficient of the first quasi-peak is The autocorrelation coefficient of the second quasi-peak is about 0.98, the autocorrelation coefficient of the second quasi-peak is about 0.96, and the autocorrelation coefficient of the first quasi-peak is about 0.94.

In the waveform of the autocorrelation coefficient, the time interval between adjacent peaks is generally a value substantially equal to the pulse interval of the pulse wave data (pulse wave waveform). However, when a noise component such as body motion is superimposed on the pulse wave waveform and the waveform is in an abnormal state, the quasi-peak does not clearly appear in the waveform, and the waveform shape as shown for the body motion waveform in FIG. 9 is exhibited.

Returning to FIG. 6, in the following S730, S720
The central peak is extracted from the waveform of the autocorrelation coefficient calculated in step 1, and a process of detecting three quasi-peaks that sequentially appear after the central peak is performed. Then, a peak coefficient value P representing the autocorrelation coefficient of each of the first to third quasi-peaks
(1), P (2), P (3) are calculated, and the peak time interval d represents the time interval between adjacent peaks of the central peak and the first to third quasi-peaks.
(1), d (2), d (3) are detected. The resolution at this time is 50 [msec].

At the next S740, "The average pulse interval PI (n) calculated at S330 is calculated for each of the three peak time intervals d (1), d (2), d (3) calculated at S730. , The peak time interval d (k) is smaller than the time interval minimum value obtained by subtracting the sampling period (0.05 [sec]) of the pulse wave waveform, and the peak time interval d
It is smaller than the maximum value of the time interval obtained by adding the sampling period of the pulse wave waveform to (k) "(hereinafter, referred to as time interval condition C3)," 3 peak coefficient values P (1) calculated in S730. , P (2), P (3) are all greater than a predetermined peak coefficient determination reference value (0.9 in this embodiment) (hereinafter referred to as coefficient value condition C4). If both the time interval condition C3 and the coefficient value condition C4 are satisfied, an affirmative decision is made and S7
50, and time interval condition C3 or coefficient value condition C4
If at least one of the above is not satisfied, a negative determination is made and the process proceeds to S760.

In S750, it is determined that the pulse wave data (pulse wave waveform) in the current detection section is a normal pulse wave waveform. In S760, it is determined that the pulse wave data (pulse wave waveform) in the current detection section is abnormal, the waveform abnormality determination flag Fm is set to the set state, and the current pulse wave data is abnormal. To record.

When the processing of S750 or S760 ends, the "abnormality determination processing using the autocorrelation function" ends, and the processing shifts to the complex demodulation analysis execution processing again. In the "abnormality determination process using the autocorrelation function" configured by the above processing contents, the autocorrelation coefficient of the pulse wave data (pulse waveform) stored in S120 is calculated, and the peak is calculated from the waveform of the autocorrelation coefficient. The information (peak time interval d (k) and peak coefficient value) regarding the frequency band component most included in the pulse wave data is detected, and the peak time interval d is extracted.
A process of determining whether or not the pulse wave data is normal is performed based on (k) and the peak coefficient value.

When the "abnormality judgment process using the autocorrelation function" is completed and the process goes to the complex demodulation analysis execution process again, the following S220 is executed. In S220, based on the state of the waveform abnormality judgment flag Fm, this time It is determined whether or not the pulse wave data in the detection section is normal, and if the determination is affirmative, the process proceeds to S230, and if the determination is negative, S260.
Move to.

When an affirmative decision is made in S220 and the flow shifts to S230, the initial normality decision flag a is changed to the set state (a = 1) in S230. In subsequent S240, the average pulse interval PI (n) and the average pulse interval variation value HF calculated from the pulse wave data (pulse wave waveform) of the current detection section.
(N) is stored in the storage unit (memory or the like) included in the data processing device 19 and displayed on the display unit (liquid crystal panel or the like) included in the data processing device 19.

At next S250, the average pulse interval PI calculated from the pulse wave data (pulse wave waveform) of the current detection section.
(N) and the average pulse interval variation value HF (n) are recorded and updated as a normal average pulse interval PI (m) and a normal average pulse interval variation value HF (m), respectively.

When a negative determination is made in S220 and the process proceeds to S260, it is determined in S260 whether or not the initial normality determination flag a is in the set state (a ≠ 0). If an affirmative determination is made, the process proceeds to S270. , If the determination is negative, S170
Move to. That is, after the pulse wave waveform analysis process is started, the initial normality determination flag a is in the reset state (a = 0) while the pulse wave data stored in S120 is in the abnormal state.
Therefore, a negative determination is made in S260, and the process proceeds to the next detection section. Further, after the pulse wave waveform analysis process is started, if there is at least one detection section in which the pulse wave data stored in S120 is determined to be normal, the initial normality determination flag a is set in S230. State (a
Since the setting is changed to = 1), an affirmative determination is made in S260, and the process proceeds to S270.

In S270, in the past detection section,
Normal mean pulse interval PI (m) and normal mean pulse interval variation value HF (m) recorded by the processing in S250
Among these, using the latest normal average pulse interval PI (m) and normal average pulse interval variation value HF (m), the average pulse interval PI (n) and average pulse interval variation value HF (n) of this time are used.
To correct. Then, the corrected average pulse interval PI (n)
And the average pulse interval variation value HF (n) are stored in a storage unit (memory or the like) and a display unit (liquid crystal panel or the like).
Perform the processing to be displayed on.

When the negative determination is made in S160, the negative determination in S260, or the processing in S250 or S270 is completed, the processing proceeds to S170, and in S170, the increment processing (n in which the data storage number counter n is incremented by 1)
= N + 1) is performed. When the process in S170 ends, the process moves to S120 again, and the pulse wave data storage process (sampling process) in the next detection section is started.

The "pulse wave waveform analysis process" constituted by the above processing contents detects pulse wave data (pulse wave waveform) from the detection signal from the pulse wave sensor 11 and performs complex demodulation analysis, A process of calculating the pulse interval PI and the pulse interval variation value HF is performed. Then, the data processing device 19 separately executes a process of calculating the reciprocal of the pulse interval PI calculated in the “pulse wave waveform analyzing process” to calculate the pulse rate.

In the pulse wave measuring device 1 of this embodiment, S310 of the complex demodulation analysis execution process corresponds to the pulse interval detecting means described in the claims, and S140 of the pulse wave waveform analysis process is executed. , Power maximum frequency detection means, and first, second, and third power maximum frequency detection availability determination means, and pulse wave waveform analysis processing S150, S190, and S260 correspond to center frequency setting means.

Further, in the abnormality determination process using the difference in pulse intervals, S410 corresponds to the pulse interval difference absolute value calculating means described in the claims, and S460 corresponds to the first pulse wave normality determining means. , S420, S430, S
Reference numeral 440 corresponds to the difference normal determination reference value setting means.

Further, S350 of the complex demodulation analysis processing is
Corresponding to the pulse interval variation value detection means described in the claims, S610 of the abnormality determination process using the increase / decrease rate corresponds to the pulse interval variation rate calculation means and the pulse interval variation value increase / decrease rate calculation means, S62 of the abnormality determination process using the rate
0, S630, and S640 correspond to the second pulse wave waveform normality determination means.

Further, S720 of the abnormality determination process using the autocorrelation function corresponds to the autocorrelation coefficient calculating means described in the claims, and S730 of the abnormality determination process using the autocorrelation function is the peak. Corresponding to the coefficient time interval detection means, S740 of the abnormality determination process using the autocorrelation function,
It corresponds to a third pulse wave normality determining means.

As described above, in the pulse wave measuring apparatus 1 of the present embodiment, when performing complex demodulation conversion on the detected pulse wave data, the center frequency of the analysis target frequency is obtained by the FFT processing in S140. Of the frequency characteristics of the wave data, the frequency at the maximum power value (maximum power frequency, peak variable peak (n)) is set. Since the maximum power frequency represents the highest frequency among the frequency components included in the pulse waveform, it is a frequency band substantially equal to the frequency band corresponding to the pulse interval.

Therefore, according to the complex demodulation analysis of the present embodiment, the frequency component corresponding to the pulse interval can be reliably extracted from the pulse wave waveform, so that the decrease in the pulse interval detection accuracy when the pulse waveform is attenuated is suppressed. In addition, it is possible to suppress the influence of noise components having different frequency bands. Further, since the pulse interval changes with the passage of time, by detecting the maximum power frequency for each detection section and updating the center frequency fc of the analysis target frequency band,
It becomes possible to set the center frequency in the complex demodulation fine weather machine to an appropriate value according to the fluctuation of the pulse interval.

Further, in the pulse wave measuring device 1, when the normal maximum power frequency cannot be detected in the frequency identification of the pulse wave data calculated by the FFT processing, the normal maximum power frequency is detected in the past. Normal peak variable peak which is the peak variable peak (n) when it is determined to be possible
k (m) is set to the center frequency variable fc (n). Accordingly, even when the maximum power frequency cannot be detected from the frequency characteristics of the pulse wave data calculated by the FFT process, the center frequency fc of the analysis target frequency band in the complex demodulation analysis can be used for detecting the pulse interval. It can be set to a suitable value.

Therefore, the pulse wave measuring apparatus 1 of the present embodiment can suppress the deterioration of the detection accuracy of the pulse interval even when the maximum power frequency cannot be detected, and suppress the influence of noise. it can. Then, in S140, when determining whether or not the maximum power frequency can be detected, it is determined that there is a quasi-peak having a power equal to or higher than the quasi-peak determination reference ratio (50%) with respect to the maximum power in the analysis target section. Further, when it is determined that the quasi-peak frequency and the power maximum frequency are not included in the allowable frequency range, it is determined that the normal power maximum frequency cannot be detected.

As a result, it is possible to prevent the frequency at the quasi-peak generated by the influence of noise or the like from being erroneously set to the center frequency fc used in the complex demodulation analysis, and to prevent the detection accuracy from decreasing. Therefore, the pulse wave measuring apparatus 1 of the present embodiment can appropriately determine whether the maximum power frequency can be detected or not, and the center frequency fc is set to an inappropriate value. In addition, it is possible to prevent the occurrence of a large error in various information (pulse interval, pulse rate, etc.) calculated based on the pulse wave data due to the abnormality of the pulse wave data.

Further, the pulse wave measuring apparatus 1 of the present embodiment is S32 in the "abnormality determination process using the difference between pulse intervals".
The difference comparison time (1
[Sec]), two pulse intervals pi differing in detection time
Pulse interval difference absolute value pid (x) which is the absolute value of the difference of
Is calculated, it is determined that the pulse wave data is normal when the pulse interval difference absolute value pid (x) is smaller than the difference normal determination reference value J, and the pulse interval difference absolute value pid (x) is determined to be normal. When it is equal to or larger than the reference value J, it is determined that the pulse wave data is abnormal.

That is, the pulse interval calculated from the normal pulse wave data does not change abruptly within a short time (for example, 1 [sec]), so that it is within a time range in which the pulse wave waveform does not suddenly change. Whether or not the pulse wave data is normal can be determined based on the difference between the two pulse intervals whose detection timings differ by the difference comparison time set to.

The difference comparison time is not limited to 1 [sec], but may be within a time range in which the pulse wave data does not change suddenly (for example, 5 seconds).
If it is [sec] or less), it may be set to an appropriate value according to the application. When it is determined that the pulse wave data is abnormal, the latest normal average pulse interval PI (m) and the normal average pulse interval change value HF (m) are updated in S270 of the “pulse wave waveform analysis process”. Is used to correct the average pulse interval PI (n) and the average pulse interval variation value HF (n) of this time. In this way, the correction process is performed using the latest normal pulse wave data (specifically, the amount of information calculated based on the normal pulse wave data) of the normal pulse wave data detected when it was determined to be normal in the past. By doing so, it is possible to prevent erroneous pulse intervals and pulse interval fluctuation values from being calculated based on abnormal pulse wave data. Also, the normal mean pulse interval P
Since the latest value of I (m) and the normal mean pulse interval variation value HF (m) is used, the actual pulse interval and the pulse interval variation value in the current detection section should be close to the values. Can be corrected.

Therefore, the pulse wave measuring apparatus 1 of this embodiment can judge whether the pulse wave data is normal or abnormal, and even if it is judged that the pulse wave data is abnormal, Various information calculated based on pulse wave data by correcting the data (pulse interval, pulse rate, pulse interval fluctuation value, etc.)
It is possible to suppress the occurrence of a large error in.

Next, in the "abnormality determination process using the difference between pulse intervals", it is determined that the normal maximum power frequency can be detected in the FFT process in S140 (S42).
If the affirmative determination is 0), the maximum power frequency detected from the pulse wave data of the current detection section (peak variable p
The value of the predetermined difference determination reference ratio with respect to the reciprocal of eak) is set as the difference normal determination reference value J.

That is, the reciprocal of the maximum power frequency has a value substantially equal to the actual pulse interval, and the pulse interval difference absolute value pid is not more than a predetermined ratio to the pulse interval if the pulse wave data is normal. Therefore, the ratio of the maximum value of the absolute value of the pulse interval difference to the pulse interval when the pulse wave data is normal is set as the difference determination reference ratio, and the value of the difference determination reference ratio to the reciprocal of the power maximum frequency is set to the normal difference. By setting the judgment reference value J, it is possible to appropriately judge whether or not the pulse wave data is normal.

Further, in the "abnormality determination process using the difference between pulse intervals", it is determined that the normal maximum power frequency cannot be detected in the FFT process in S140 (S4).
20), the average pulse rate P is normal.
A value of a predetermined difference determination reference ratio with respect to the latest normal average pulse interval PI (m) of I (m) is set as a difference normal determination reference value J.

As described above, when the maximum power frequency cannot be detected from the frequency characteristic of the pulse wave data, the difference normality determination reference value J is set by using the normal pulse interval PI (m), and the difference normality determination value J is set. It is possible to prevent the normality determination reference value J from being set to an abnormal value. In addition, since the latest numerical value is used among the normal pulse interval PI (m) detected in the past, it becomes a numerical value close to the difference normal determination reference value J suitable for the actual pulse wave data in the current detection section. Can be corrected to.

Therefore, the pulse wave measuring apparatus 1 of the present embodiment can set the difference normality determination reference value J to a value close to an appropriate value even if the maximum power frequency cannot be detected, and the pulse wave data is normal. Since it is possible to determine whether or not there is a significant error in various information (pulse interval, pulse rate, etc.) calculated based on the pulse wave waveform due to abnormality in the pulse wave data is suppressed. be able to.

The difference determination reference ratio may be set to a ratio of the maximum value that the pulse interval difference absolute value can take to the pulse interval when the pulse wave data is normal, for example, 4
It is recommended to set a value of 0% or less. Next, in the "abnormality determination process using each increase / decrease rate of the pulse interval and the pulse interval variation value", the pulse interval variation rate PI (n) / PI (m) and the pulse interval variation value variation rate HF (n) / The determination result of whether the changing tendency of HF (m) is in the same direction, the pulse interval increase / decrease rate PI (n) / PI (m), and the pulse interval change value increase / decrease rate H
Based on the absolute value of the difference between F (n) / HF (m) and the comparison result with the increase / decrease rate determination reference value, it is determined whether or not the pulse wave data in the current detection section is normal. .

That is, if the pulse wave data is normal, the change tendency of the pulse interval increase / decrease rate PI (n) / PI (m) and the pulse interval change value increase / decrease rate HF (n) / HF (m) is substantially zero. They are equal, and both change in the same direction (either the increasing tendency or the decreasing tendency). From this, whether the pulse waveform is normal based on the respective changing directions of the pulse interval increase / decrease rate PI (n) / PI (m) and the pulse interval variation value increase / decrease rate HF (n) / HF (m). It can be determined whether or not.

Each increase rate has an increasing tendency and a decreasing tendency. Specifically, the pulse interval increase / decrease rate P
I (n) / PI (m) and pulse interval fluctuation value increase / decrease rate HF
(N) / HF (m) are both 1 or more or both are less than 1, and one of the two increasing rates has an increasing tendency and the other has a decreasing tendency. ,
In this case, one of the pulse interval increase / decrease rate PI (n) / PI (m) and the pulse interval change value increase / decrease rate HF (n) / HF (m) is 1 or more and the other is less than 1. The determination condition in S620 is set based on this condition.

Even if all the increase / decrease rates change in the same direction, if the increase / decrease rates have a large difference, it can be determined that the change tendencies are different. Therefore, when the increase / decrease rates are both increasing or decreasing (affirmative determination in S620), the absolute change rate difference is less than the first increasing / decreasing rate determination reference value (affirmative in S640). If it is determined), the pulse wave data is determined to be normal, and the increase / decrease difference absolute value is the first value.
When the increase / decrease rate determination reference value is equal to or larger than the reference value (negative determination in S640), it is determined that the pulse wave data is abnormal.

Even when the increase / decrease rates change in different directions, if the difference between the increase / decrease rates is small, it can be determined that the change tendencies are substantially equal. Therefore, when each increase / decrease rate changes in a different direction (when a negative determination is made in S620), the absolute change rate difference is less than the second increase / decrease rate determination reference value (when an affirmative determination is made in S630). When the pulse wave waveform is determined to be normal and the increase / decrease rate difference absolute value is greater than or equal to the second increase / decrease rate determination reference value (when a negative determination is made in S630)
In addition, it is determined that the pulse wave waveform is abnormal.

Therefore, the pulse wave measuring apparatus 1 of the present embodiment determines whether the pulse wave waveform is normal or abnormal based on the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate.
Since the determination is performed using not only the change tendency of each increase rate but also the difference of each increase rate, the determination accuracy can be improved. Then, when it is determined that the pulse wave data is abnormal, the correction process is performed in S270 of the “pulse wave waveform analysis process” so that an incorrect pulse interval or pulse is detected based on the abnormal pulse wave data. It is possible to prevent the interval variation value from being calculated.

Next, in the "abnormality determination process using the autocorrelation function", the autocorrelation coefficient of the pulse wave data (pulse waveform) is calculated, the peak is detected from the waveform of the autocorrelation coefficient, and the pulse is detected. The information (peak time interval d (k) and peak coefficient value) about the frequency band component most included in the wave data is extracted, and the pulse wave data is normal based on the peak time interval d (k) and peak coefficient value. It is determined whether or not

That is, the autocorrelation coefficient of the pulse wave data calculated using the autocorrelation function has peaks corresponding to the frequency characteristics of the pulse wave data, so that the time interval between adjacent peaks (peak time interval) ) Is a value approximately equal to the actual pulse interval of the living body. From this, whether the pulse waveform is normal or not is based on the comparison result of the pulse interval PI detected by the complex demodulation analysis and the peak time interval d (k) detected based on the autocorrelation coefficient. Can be determined. That is, the pulse interval PI is the peak time interval d
When it is substantially equal to (k), it can be determined that the pulse wave waveform is normal, and when the pulse interval PI has a value different from the peak time interval d (k), it can be determined that the pulse wave waveform is abnormal. .

In addition, in the calculated waveform of the autocorrelation coefficient, the autocorrelation coefficient of the true peak corresponding to the frequency band most included in the pulse wave data is a predetermined ratio to the autocorrelation coefficient of the central peak ( For example, the value is 90% or more. Therefore, with respect to the quasi-peaks other than the central peak, it can be determined whether or not the quasi-peak is a true peak based on whether or not the peak coefficient value (autocorrelation coefficient) is equal to or higher than a predetermined ratio.

Therefore, in S740, the condition for comparing the pulse interval PI and the peak time interval d (k) (time interval condition C
3) and the determination condition (coefficient value condition C4) of the peak coefficient value P (k), it is determined whether or not the pulse wave data is normal. It should be noted that the pulse wave waveform cannot extract a waveform fluctuation in a time shorter than the sampling period, and thus an error corresponding to the sampling period may occur in the advance direction or the delay direction on the time axis. Therefore, in the time interval condition C3, the minimum value of the time interval is set to a value obtained by subtracting the sampling period of the pulse wave waveform from the peak time interval, and the maximum value of the time interval is set to the sampling period of the pulse wave waveform at the peak time interval. It is set to the added value.

Therefore, the time interval condition C3 and the coefficient value condition C
By providing the process of S740 for determining whether or not the pulse wave data is normal based on 4, it is possible to perform more reliable determination and improve the determination accuracy. Further, the pulse wave measuring apparatus 1 of the present embodiment does not make a normal determination of the pulse wave waveform based on one peak time interval d (k), but based on three peak time intervals d (k). Since the normal determination of the pulse wave waveform is performed, the number of comparisons increases, and more accurate determination can be performed.

Here, using the conventional pulse wave measuring apparatus that does not perform the correction processing based on the abnormality determination result and the pulse wave measuring apparatus 1 of this embodiment that performs the correction processing, the pulse interval PI is obtained from the same pulse wave data. FIG. 10 shows the measurement result when the measurement for calculating the pulse interval variation value HF and the measurement for calculating the pulse interval variation value HF are executed.
The measurement results of the conventional pulse wave measuring device are shown in FIG.
FIG. 10B shows the measurement result of the pulse wave measuring device 1 of this embodiment.

According to the measurement result shown in FIG. 10 (a), in the conventional pulse wave measuring device that does not perform the correction process, the pulse interval variation value HF abruptly changes and rises to the outside of the display area. It can be seen that there is a part where the waveform is disturbed by the influence of noise. On the other hand, according to the measurement results shown in FIG. 10A, it can be seen that there is no portion where the pulse interval variation value HF changes abruptly, and the influence of noise can be suppressed.

Therefore, it can be seen from the above measurement results that the pulse interval can be detected by suppressing the influence of noise by using the pulse wave measuring apparatus 1 of this embodiment. Since the pulse wave measuring device 1 of the present embodiment can detect an abnormality in the pulse wave data, it can also be used for the purpose of detecting arrhythmia.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and can take various modes. For example, in the above embodiment, three quasi-peaks in the autocorrelation coefficient are detected, but the number is not limited to three, and the number of detected peaks may be increased to further improve the detection accuracy. . Alternatively, in applications where high detection accuracy is not required,
The number of detected peaks may be reduced.

As the abnormality determination processing, "abnormality determination processing using difference between pulse intervals", "abnormality determination processing using each increase / decrease rate of pulse interval and pulse interval variation value", and "autocorrelation function" were used. It is not necessary to include all the "abnormality determination processing", and the pulse wave measuring device may be configured to include any one or two.

Further, the processing in S140 as the maximum power frequency detection possibility determining means does not need to be combined into one step, and "abnormality determining processing using difference in pulse interval" and "pulse interval and pulse interval variation" May be provided in the "abnormality determination process using each increase / decrease rate of value".

Moreover, the numerical values (judgment reference value, frequency band to be analyzed, etc.) used in each processing are not limited to the above numerical values, and pulse wave measurement is performed by setting an appropriate value according to the application. It is possible to improve the detection accuracy of the pulse interval and the pulse rate. For example, the first increase / decrease rate determination reference value is 0.6
The second increase / decrease rate determination reference value is not limited to 0.
It is not limited to 2, and the difference comparison time is 1
It is not limited to [sec].

[Brief description of drawings]

FIG. 1A is a schematic configuration diagram of a pulse wave measuring device including a pulse wave sensor and a data processing device, and FIG.
It is explanatory drawing which represents typically the cross-sectional state at the time of attaching a pulse wave sensor to a human body.

FIG. 2 is a flowchart showing the processing contents of pulse wave waveform analysis processing.

FIG. 3 is a flowchart showing the processing contents of complex demodulation analysis execution processing.

FIG. 4 is a flowchart showing the processing contents of abnormality determination processing using the difference between pulse intervals.

FIG. 5 is a flowchart showing the processing contents of abnormality determination processing using each increase / decrease rate of pulse intervals and pulse interval variation values.

FIG. 6 is a flowchart showing the processing contents of abnormality determination processing using an autocorrelation function.

FIG. 7 is an explanatory diagram schematically showing a detection section of pulse wave data.

FIG. 8 is a waveform example of pulse wave data, pulse intervals, and pulse interval difference absolute values.

FIG. 9 is a waveform example of an autocorrelation coefficient.

FIG. 10A is a measurement result of a pulse interval and a pulse interval variation value in a conventional pulse wave measuring device, and FIG.
[Fig. 3] is a measurement result of a pulse interval and a pulse interval variation value in the pulse wave measuring apparatus of the present embodiment.

[Description of Reference Signs] 1 ... Pulse wave measuring device, 11 ... Pulse wave sensor, 13 ... Light emitting element, 15 ... Light receiving element, 17 ... Drive circuit, 19 ... Data processing device, 21 ... Detection circuit, 23 ... AD converter, 25
… Microcomputer.

Claims (12)

[Claims] 1. A pulse wave waveform detected from a living body,
Performing complex demodulation analysis in the analysis target frequency band corresponding to the analysis of the pulse rate, with pulse interval detection means for detecting the instantaneous pulse interval from the pulse wave waveform, the living body based on the detected pulse interval Is a pulse wave measuring device for measuring the pulse rate, the frequency characteristic analysis is performed on the pulse wave waveform to detect the frequency characteristic of the pulse wave waveform, and among the frequency characteristics of the detected pulse wave waveform, the analysis target In the frequency band, a power maximum frequency detecting means for detecting a power maximum frequency which is a frequency in the power maximum value of the frequency characteristic, and a center frequency of the analysis target frequency band in the complex demodulation analysis in the pulse interval detecting means, Center frequency setting means for setting the power maximum frequency detected by the power maximum frequency detecting means, That the pulse wave measuring device. 2. A first power maximum frequency detection availability determination means for determining whether or not the power maximum frequency can be detected in the analysis target frequency band of the frequency characteristics of the pulse wave waveform, When the first power maximum frequency detection availability determination means determines that the power maximum frequency is detectable, the center frequency setting means sets the power maximum frequency detected at that time to the center frequency of the analysis target frequency band. When the power maximum frequency is set and the power maximum frequency is determined to be undetectable by the first power maximum frequency detection availability determination unit, the normal power maximum frequency that is the power maximum frequency detected when it is determined to be detectable in the past. The latest normal power maximum frequency among them is set to the center frequency of the analysis target frequency band. Pulse wave measuring apparatus according to 1. 3. In the pulse interval detected by the pulse interval detecting means, the detection timing differs by a difference comparison time set within a time range in which the pulse wave waveform does not change abruptly.
A pulse interval difference absolute value calculating means for calculating the difference between the two pulse intervals, and calculating an absolute value of the calculated difference as a pulse interval difference absolute value; and the pulse interval difference absolute when the pulse wave waveform is normal. The difference normal judgment reference value set to the maximum value and the pulse interval difference absolute value are compared, and when the pulse interval difference absolute value is smaller than the difference normal judgment reference value, the pulse wave waveform is normal. The first pulse wave waveform normality determining means for determining that the pulse wave waveform is abnormal when the pulse interval difference absolute value is equal to or more than the difference normality determination reference value. The pulse wave measuring device according to claim 1 or 2, which is characterized. 4. A difference normal judgment reference value setting means for setting a value of a predetermined difference judgment reference ratio with respect to the reciprocal of the maximum power frequency as the difference normal judgment reference value, and a difference normal judgment reference value setting means. The pulse wave measuring device described. 5. A second power maximum frequency detection availability determination means for determining whether or not the power maximum frequency can be detected in the analysis target frequency band of the frequency characteristics of the pulse waveform, The difference normal determination reference value setting means, when the second power maximum frequency detection availability determination means determines that the power maximum frequency can be detected,
A value of a predetermined difference determination reference ratio with respect to the reciprocal of the power maximum frequency detected at that time is set as a difference normal determination reference value, and the second power maximum frequency detection availability determination unit determines that the power maximum frequency is not detected. If it is determined that it is possible, a predetermined difference determination reference ratio with respect to the latest normal pulse interval among the normal pulse intervals that are the pulse intervals detected by the pulse interval detection means when it is determined to be detectable in the past. The pulse wave measuring device according to claim 4, wherein the value of is set as the normal difference determination reference value. 6. A third power maximum frequency detection availability determination means for determining whether or not the power maximum frequency can be detected in the analysis target frequency band of the frequency characteristics of the pulse wave waveform, Second pulse corresponding to the analysis of the parasympathetic nerve activity of the living body for the pulse interval detected by the pulse interval detecting means
Performing complex demodulation analysis in the frequency band to be analyzed, the pulse interval variation value detecting means for detecting the pulse interval variation value from the pulse interval, the latest pulse interval detected this time by the pulse interval detecting means, and the past in the past. When the third power maximum frequency detection availability determination unit determines that the power maximum frequency is detectable, the latest normal pulse interval among the normal pulse intervals that are the pulse intervals detected by the pulse interval detection unit A pulse interval increase / decrease rate calculating means for calculating a pulse interval increase / decrease rate representing a ratio, the latest pulse interval change value detected this time by the pulse interval change value detecting means, and the third power maximum frequency detection availability determination in the past. The pulse interval variation value detected by the pulse interval variation value detecting means when the power maximum frequency is determined to be detectable by the means. A pulse interval variation value increase / decrease rate calculating means for calculating a pulse interval variation value increase / decrease rate that represents a ratio of the normal pulse interval variation value to the latest normal pulse interval variation value, and the pulse interval increase / decrease rate and the pulse interval variation value When the increase / decrease rate is either increasing or decreasing, it is determined that the pulse waveform is normal, and one of the pulse interval increasing / decreasing rate and the pulse interval variation value increasing / decreasing rate has an increasing tendency. And when the other has a decreasing tendency, the second pulse wave waveform normality judging means for judging that the pulse wave waveform is abnormal is provided, and any one of claims 1 to 5 is provided. The pulse wave measuring device described. 7. The second pulse wave waveform normality determining means determines the pulse interval increase / decrease rate when the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate both increase or decrease. A first increase / decrease rate determination in which an increase / decrease rate difference absolute value that is an absolute value of a difference from the pulse interval variation value increase / decrease rate is set to the maximum value of the increase / decrease rate difference absolute value when the pulse wave waveform is normal. When it is less than a reference value, it is determined that the pulse wave waveform is normal, and when the increase / decrease rate difference absolute value is greater than or equal to the first increase / decrease rate determination reference value, the pulse wave waveform is abnormal. The determination is performed, The pulse wave measuring device according to claim 6. 8. The second pulse wave normality determining means determines, when one of the pulse interval increase / decrease rate and the pulse interval variation value increase / decrease rate is increasing and the other is decreasing, the pulse interval increasing / decreasing rate. Second increase / decrease set to the maximum value of the increase / decrease rate difference absolute value when the pulse wave waveform is normal, in which the increase / decrease rate difference absolute value that is the absolute value of the difference between the pulse rate variation value increase / decrease rate When it is less than the rate determination reference value, it is determined that the pulse wave waveform is normal, and when the increase / decrease rate difference absolute value is greater than or equal to the second increase / decrease rate determination reference value, the pulse wave waveform is abnormal. The pulse wave measuring device according to claim 6 or 7, wherein it is determined that there is. 9. An autocorrelation coefficient calculating means for calculating an autocorrelation coefficient relating to a time interval of the pulse wave waveform using an autocorrelation function, and the self-correlation relationship calculated by the autocorrelation coefficient calculating means. In terms of numbers, a central peak appearing in the center of the autocorrelation coefficient and a first peak which is a peak next to the central peak are detected, and the autocorrelation coefficient of each of the central peak and the first peak is detected. A peak coefficient time interval detecting means for detecting a central peak coefficient value and a first peak coefficient value, and detecting a first peak time interval representing a time interval between the central peak and the first peak; and the pulse interval detection. The pulse interval detected by the means,
Third pulse wave waveform normality determination means for determining whether or not the pulse wave waveform is normal based on a comparison result with the first peak time interval detected by the peak coefficient time interval detection means, The pulse wave measuring device according to any one of claims 1 to 8, which is provided. 10. The third pulse waveform normality determining means is characterized in that the pulse interval detected by the pulse interval detecting means is:
It is larger than a time interval minimum value obtained by subtracting the pulse wave waveform sampling period from the first peak time interval and smaller than a time interval maximum value obtained by adding the pulse wave waveform sampling period to the first peak time interval. Is the case
The pulse wave measuring device according to claim 9, further comprising: determining that the pulse wave waveform is normal when the first peak coefficient value is larger than a predetermined peak coefficient determination reference value. 11. The peak coefficient time interval detecting means detects, in addition to the central peak and the first peak, at least one or more peaks that sequentially appear after the first peak, and detects each of the detected peaks. While detecting the peak coefficient value representing the autocorrelation coefficient, for each of the detected peaks to detect the peak time interval representing the time interval of the peak adjacent to each other, the third pulse wave waveform normal determination means, The pulse interval detected by the pulse interval detection means,
10. It is determined whether or not the pulse wave waveform is normal based on a comparison result with all the peak time intervals detected by the peak coefficient time interval detecting means. The pulse wave measuring device according to claim 10. 12. The pulse wave measuring device according to claim 2, 5, or 6, wherein the power maximum frequency detection feasibility determining means is one of the frequency characteristics of the pulse wave waveform. In the frequency band to be analyzed, in addition to the maximum peak that is the power maximum value, it is determined whether or not there is a quasi-peak that has a power of a predetermined quasi-peak determination reference ratio or more to the power maximum value, and the quasi-peak is When it is determined that there is not, it is determined that the power maximum frequency is detectable, when it is determined that the quasi-peak exists, further,
The frequency of the quasi-peak and the maximum power frequency are
Determine whether included in the allowable frequency range allowed as the same frequency, the frequency of the quasi-peak and the power maximum frequency,
If it is determined to be included in the allowable frequency range,
It is determined that the power maximum frequency can be detected, the frequency of the quasi-peak and the power maximum frequency,
The pulse wave measuring device, wherein when it is determined that the power maximum frequency is not included in the allowable frequency range, it is determined that the power maximum frequency cannot be detected.