JP2011115459A - Device and method for detecting biological information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for detecting biological information, attaining compatibility between reduction of measuring time and high-accuracy biological information measurement. <P>SOLUTION: This biological information detecting device filters a pulse wave signal obtained from a living body to obtain pulse wave data using a BPF part 7 whose pass frequency band is variable, and measures periodic data of the pulse wave signal based on the pulse wave data. In synchronization with a control timing, the basic frequency of the pulse wave signal is computed from the immediately before periodic data of the pulse wave for one beat to set the pass frequency band of the BPF 7 based on the basic frequency beat by beat. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a biological information detection apparatus and a biological information detection method capable of detecting biological information from a pulse wave signal.

  Conventionally, as a device for grasping the state of a living body (human body) using a pulse wave signal, a living body information measuring device capable of measuring living body information with high accuracy without being affected by noise due to body movement of the living body Is known (see Patent Document 1).

  The technique of this patent document 1 is not based on the pulse rate calculated from the currently measured pulse wave, but using a pulse rate that has been averaged for several tens of seconds by an external pulse meter (for later pulse wave detection). This is to set a so-called frequency tracking filter that tunes a variable bandpass filter. Specifically, by continuously maintaining the optimum filter frequency range using the pulse rate of the external pulse meter, only the pulse wave signal is allowed to pass and noise due to body movement of the living body is removed.

  As an apparatus used for this technique, for example, as shown in FIG. 13, a pulse wave sensor P1, a pulse wave numerical value conversion unit (A / D converter) P2, a calculation unit P3 which is an electronic control unit, and an external pulse meter An apparatus including P4 is known, and a calculation unit P3 includes a BPF unit P5 that is a frequency tracking filter, a frequency conversion unit P6 that performs Fourier transform of pulse wave data, and biological information that detects biological information data. And a detector P7.

  Then, in the calculation unit P3 of this apparatus, as shown in FIG. 14, the signal (human body pulse wave signal) obtained from the pulse wave sensor P1 is filtered, and the pulse wave data at the predetermined time is subjected to Fourier transform (FFT). The biometric information data indicating the state of the living body is detected using the converted data.

JP 2004-202190 A

  However, in the technique of Patent Document 1 described above, since the filter itself has the ability to tune with the pulse rate, there is an advantage that the measurement accuracy is high, but the pulse rate is measured with an external pulse meter and is constant. Since the biological information is calculated by extracting a specific frequency component by Fourier transforming the pulse wave signal sampled for a period, it takes 10 to 20 seconds to obtain the measurement result of the biological information after the device is mounted on the human body. There is a problem that it cannot be used for applications in which it is desired to immediately obtain biological information from a pulse wave.

  In particular, in the case of a device that uses biometric information as a starting condition (for example, a device that detects the blood alcohol concentration when the engine is started), if biometric information cannot be obtained immediately, the user is stressed. was there.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a biological information detection apparatus and a biological information detection method capable of both reducing measurement time and measuring biological information with high accuracy. is there.

  (1) The invention of claim 1 has a variable frequency band, a filter unit to which a pulse wave signal (human body pulse signal) obtained from a living body is input, and pulse wave data output from the filter unit (I.e., a pulse wave signal from which noise or the like has been removed by a filter) and a period measuring unit that measures period data of the pulse wave signal The basic frequency of the pulse wave signal is calculated from the period data calculated by the period measurement unit based on the pulse wave data obtained from the pulse wave, and passes through the filter unit based on the basic frequency for each beat. A frequency band is set.

  In the present invention, the fundamental frequency of the pulse wave signal is calculated from the period data (corresponding to one immediately preceding pulse) calculated by the period measurement unit based on the pulse wave data obtained from the immediately preceding pulse wave signal. Since the pass frequency band of the filter unit is set for each beat based on the fundamental frequency, it is quicker than the conventional method using a pulse rate that is averaged for several tens of seconds by an external pulse meter. Further, the pass frequency band of the filter unit can be set within a preferable range.

  In other words, based on the period data for each previous beat, it is possible to obtain only a pulse wave signal from which noise and the like are removed by setting an optimum pass frequency band according to the state of the living body for each beat. Biological information with high accuracy can be obtained promptly.

Here, the period data includes a period or a value obtained from the period (for example, a frequency that is the reciprocal of the period). The fundamental frequency is the pulse rate per second. Further, the immediately preceding pulse wave signal indicates a pulse wave signal one beat before the pulse wave signal for one beat currently being measured.
(2) The invention according to claim 2 is characterized in that the passing frequency band is variable, and the pulse wave signal obtained from the living body is input, and the pulse wave data output from the filter unit is used as the pulse wave data. A period measurement unit that measures period data of the wave signal, a pulse height measurement unit that measures the pulse height of the pulse wave signal based on the pulse wave data output from the filter unit, and a pulse that is measured by the period measurement unit A biological information calculation unit that calculates biological information indicating the state of the living body using at least one of the period data of the wave signal and the pulse height data of the pulse wave signal measured by the pulse height measurement unit; A biological information detection device, wherein a fundamental frequency of the pulse wave signal is calculated from period data calculated by the period measurement unit based on the pulse wave data obtained from the immediately preceding pulse wave signal, and one pulse beat Every And setting the pass frequency band of the filter unit based on serial fundamental frequency.

  In the present invention, the fundamental frequency of the pulse wave signal is calculated from the period data (corresponding to one immediately preceding pulse) calculated by the period measurement unit based on the pulse wave data obtained from the immediately preceding pulse wave signal. Since the pass frequency band of the filter unit is set for each beat based on the fundamental frequency, compared with the conventional method using a pulse rate that has been averaged for several tens of seconds by an external pulse meter. The pass frequency band of the filter unit can be set within a preferable range.

  In other words, based on the period data for each previous beat, it is possible to obtain only a pulse wave signal from which noise and the like are removed by setting an optimum pass frequency band according to the state of the living body for each beat. Biological information with high accuracy can be obtained promptly.

Here, examples of the biological information include information indicating the state of the living body such as blood alcohol concentration and pulse wave number.
(3) In the invention of claim 3, the pulse wave data is first-order differentiated, and the calculation result is calculated by the filter unit, the period measuring unit, the wave height calculating unit, and the biological information calculation. This is used to set the calculation timing when performing the calculation of the unit.

  In the present invention, pulse wave data is subjected to first-order differentiation to determine the state of the pulse wave signal, specifically the timing at which the pulse wave changes, for example, the peak of the pulse wave (maximum value: for example, the maximum value timing), the bottom of the pulse wave ( Minimum value (for example, minimum value timing) can be detected. Therefore, the timing indicated by the value obtained by first-order differentiation of the pulse wave data can be used as timing data (control timing) when the filter unit, the pulse height measurement unit, the period measurement unit, and the biological information calculation unit perform calculations. Thereby, since various calculations for every beat can be performed synchronously, the calculation can be quickly performed as a whole.

  For example, at the minimum timing obtained from the pulse wave data, based on the pulse wave data for one beat so far, the calculation of the wave height in the pulse wave of the previous one beat, the calculation of the period (the reciprocal thereof), biological information Can be calculated.

  (4) The invention of claim 4 corresponds to the plurality of wavelengths output from the filter unit when performing simultaneous measurement of the pulse wave of the living body using light of a plurality of wavelengths by an optical sensor. By comparing the timing of the pulse wave data, the detection error of the biological information is discriminated.

  When the wavelengths are different, the pulse wave data timing (for example, the minimum value of the pulse wave data (for example, the minimum value of the pulse wave data (e.g. Bottom) timing: minimum value timing) is different.

  When the timing of the pulse wave data is greatly different, necessary biological information may not be accurately calculated from the pulse wave data due to the influence of biological information other than the pulse wave. For example, when two types of wavelengths are used, if the timing of the bottom of the pulse wave data differs by 20% or more of the period, biological information may not be obtained with high accuracy.

  Therefore, it is possible to determine a detection error of biological information by comparing timings of pulse wave data corresponding to a plurality of wavelengths. That is, when the timing deviation is large, it can be determined that there is a detection error.

  (5) In the invention of claim 5, instead of the pulse wave data corresponding to the pulse rate of one beat, the pulse wave data corresponding to the pulse rate of two or more beats is used, and the average corresponding to one beat is averaged Period data is calculated, and the pass frequency band of the filter unit is set based on the averaged period data (for example, every beat).

  The present invention does not calculate the fundamental frequency based on the data for the immediately preceding one beat, but performs a stabilization process (for example, a process for obtaining a moving average) on the period data of two or more immediately preceding beats. The averaged period data (for example, period) is obtained, and biological information is calculated using the period data, or the pass frequency band of the filter unit is set.

According to the present invention, the measurement accuracy is improved, and biological information and the like can be calculated more quickly than in the past.
In addition, the setting of the pass frequency band of the filter unit may be performed every beat, or may be performed every two or more beats.

  (6) The invention of claim 6 is characterized in that at least one of a comb filter, a plurality of band pass filters, a high pass filter, and a low pass filter is used as the filter unit.

The present invention exemplifies a configuration of a filter that can be employed in the filter unit.
In addition, invention of Claims 7-11 has an effect similar to the invention of the said Claims 1-5, respectively.

It is explanatory drawing which shows the system configuration | structure of the biometric information detection apparatus of Example 1. FIG. It is explanatory drawing which shows timings, such as pulse wave data. It is explanatory drawing which shows the timing of the value etc. which carried out the primary differentiation of the pulse wave data. 3 is a flowchart illustrating processing in the biological information detection apparatus according to the first embodiment. It is explanatory drawing which shows states, such as a measurement mistake of pulse wave data. It is explanatory drawing which shows the comb filter used in a BPF part. It is explanatory drawing which shows the system configuration | structure of the biometric information detection apparatus of Example 2. FIG. It is explanatory drawing which shows timings, such as pulse wave data. It is explanatory drawing which shows the calculation method of blood alcohol concentration. 10 is a flowchart illustrating processing in the biological information detection apparatus according to the second embodiment. It is explanatory drawing which shows the timing of the process of the period data in the biometric information detection apparatus of Example 3. FIG. It is explanatory drawing which shows the timing of the other process of the periodic data in the biometric information detection apparatus of Example 3. FIG. It is explanatory drawing which shows the system configuration | structure of the biometric information detection apparatus of a prior art. It is explanatory drawing which shows the procedure of the signal processing of a prior art.

  Next, the biological information detection apparatus and biological information detection method of the present invention will be described with reference to the drawings.

a) First, the system configuration of the biological information detection apparatus of this embodiment will be described.
As shown in FIG. 1, in this embodiment, a pulse wave sensor 1, a pulse wave numerical value conversion unit 3 for digitally converting an analog signal from the pulse wave sensor 1, and various computations using a known microcomputer as a main part. And an arithmetic unit 5 which is an electronic control device to perform. Here, the calculation unit 5 functions as a biological information detection device.

  The pulse wave sensor 1 is a sensor that irradiates a living body with light having a predetermined wavelength (for example, 1300 nm), receives reflected light or transmitted light, and detects a pulse wave according to the state of the reflected light or transmitted light. A signal (human body pulse wave signal) detected by the pulse wave sensor 1 is output to the pulse wave value conversion unit 3.

  The pulse wave numerical value conversion unit 3 is an A / D converter that converts a human body pulse wave signal continuously sent from the pulse wave sensor 1 into digital data at regular time intervals. The signal A / D converted by the unit 3 is output to the arithmetic unit 5.

  The calculation unit 5 is a circuit for calculating digital data, and as shown functionally in the figure, among signals (digital signals) input from the pulse wave value conversion unit 3, signals in a predetermined frequency band, That is, based on the BPF unit 7 that is a variable bandpass filter that passes only the signal in the frequency band corresponding to the pulse wave, and the signal (filtered pulse wave signal) input from the BPF unit 7, the pulse height of the pulse wave signal A pulse height measurement unit 9 that measures (i.e., obtains wave height data), a cycle measurement unit 11 that measures the period T of the pulse wave signal (i.e., obtains cycle data) based on the signal input from the BPF unit 7, Based on a signal input from the BPF unit 7, a timing control unit 13 that calculates calculation timings in the wave height measuring unit 9 and the period measuring unit 11, wave height data from the wave height measuring unit 9, and a period measuring unit Enter the period data from 1, and a biological information detecting unit 15 for detecting biological information indicating the state of a living body.

  In the calculation unit 5, the pulse wave data output from the BPF unit 7 is output to the wave height measurement unit 9, the cycle measurement unit 11, and the timing control unit 13 as shown by the solid line in FIG. Necessary calculations as described later are performed. Further, the cycle data (for one beat) measured by the cycle measuring unit 11 is used for setting a pass frequency band for each beat in the BPF unit 7 as described later. Further, as indicated by the broken line in the figure, the control timing data output from the timing control unit 13 is sent to the BPF unit 7, the wave height measuring unit 9, the cycle measuring unit 11, and the biological information detecting unit 15 for each beat. Is output.

  Among these, the BPF unit 7 sets the pass frequency band for each beat using the cycle data for each pulse immediately before being sent from the cycle measuring unit 11. Specifically, the frequency f (pulse wave frequency, fundamental frequency: the reciprocal number) from the pulse wave period T immediately before the pulse wave being sent from the period measurement unit 11 (pulse wave one beat before the pulse wave currently being measured). fc = 1 / T), and the pass frequency band of the variable bandpass filter is set based on the fundamental frequency. Note that the variable band-pass filter technology for setting the pass frequency band from the frequency is a well-known digital filter technology, and therefore the description thereof is omitted (for example, see Patent Document 1).

  Further, the timing control unit 13 outputs data (time data) indicating a maximum value timing, a baseline timing, and a minimum value timing, which will be described later, for each beat as a control timing, and synchronizes with the control timing. In addition, for each beat, various calculations are performed by the BPF unit 7, the wave height measuring unit 9, the period measuring unit 11, and the biological information detecting unit 15.

  Further, the biological information detection unit 15 calculates biological information such as alcohol concentration and pulse rate for each beat, and the biological information is output to a display, a speaker, a storage device, and the like (not shown).

  That is, in the present embodiment, as will be described in detail later, the period measuring unit 11 does not perform the average pulse wave processing for several tens of seconds or the Fourier transform processing by the external pulse meter as in the past, but for each beat by the period measuring unit 11. The cycle data immediately before the measurement (cycle T) is output to the BPF unit 7 for each beat, and the BPF unit 7 filters using the fundamental frequency (1 / T) obtained from the cycle data. By setting the frequency range (pass frequency band), the function as an optimal pulse wave filter is always followed for each pulse, and the wave height data is filtered by the wave height measuring unit 9 using the data filtered by the filter. The period measurement unit 11 calculates the period data, and the biological information detection unit 15 calculates the biological information.

b) Next, signal processing performed in the biological information detection apparatus will be described.
As shown in FIG. 2, the human body pulse wave signal obtained from the pulse wave sensor 1 is A / D converted by the pulse wave numerical value conversion unit 3, filtered by the BPF unit 7, and pulse wave data (that is, A pulse wave signal from which noise has been removed by filtering the human body pulse wave signal is obtained.

Since the pulse wave data takes time for signal processing until the data is obtained, the pulse wave data is delayed by a predetermined delay time with respect to the human body pulse wave signal.
In this pulse wave data, the maximum value of the waveform (pulse wave peak (maximum value): amplitude from the reference line) is indicated by VM1 to VM4, etc., and the minimum value of the waveform (pulse wave bottom (minimum value) ): Amplitude from the reference line) is indicated by VL1 to VL4 or the like. The time from the maximum value (peak) time t1 of the waveform to the minimum value (bottom) time t2 is the wave height measurement time Δt. Here, the wave height is the difference between the peak and the bottom in the periodic fluctuation of the pulse wave signal, and the period in which the same waveform appears (for example, the time between a pair of bottoms) is indicated by periods T1 to T4. Has been.

  The wave height measuring unit 9 calculates the wave height data when, for example, the bottom of the pulse wave signal is detected (at time t2) according to the control timing (control data) calculated by the timing control unit 13. Specifically, for example, by subtracting the bottom amplitude VL1 from the peak amplitude VM1 of the waveform, the pulse height of the pulse wave is calculated (the pulse heights of other pulse waves are calculated in the same manner).

  Similarly, the period measurement unit 11 calculates period data when, for example, the bottom of the pulse wave signal is detected (at time t2) based on the control timing. Specifically, the period of the pulse wave one beat before (immediately before) is obtained using a period counter described later.

The period measuring unit 11 may obtain a frequency (f = 1 / T) that is the reciprocal number from the period T, and the BPF unit 7 may set a pass frequency band using this frequency.
Furthermore, when the bottom of the pulse wave signal is detected, for example, at the biological information detection unit 9, biological information such as alcohol concentration and pulse rate is calculated, for example.

  The alcohol concentration can be calculated based on, for example, the ratio of the wave height measured this time to the reference wave height. Here, the reference wave height is the wave height of the pulse wave of a person who is not drinking (subject), and the alcohol concentration varies depending on the wave height ratio, so that the alcohol concentration can be detected based on the wave height ratio. The pulse rate can be obtained by calculating “60 / cycle”.

Next, processing performed by the timing control unit 13 will be described.
As shown in FIG. 3, the pulse wave data output from the BPF unit 7 is first-order differentiated by the timing control unit 13.

  The primary differential value changes from + to-at the peak time t1 (maximum value timing) of the pulse wave data, and changes from-to + at the bottom time t2 (minimum value timing). Accordingly, the wave height measurement obtains the difference in amplitude between time t1 and time t2.

  Further, the primary differential maximum value is continuously measured from the time t2 (minimum value timing) until the primary differential becomes maximum. Similarly, the primary differential minimum value is continuously measured from the time t1 until the primary differential becomes minimum.

Furthermore, the wave height measurement starts at time t1 (maximum value timing) and ends at time t2 (minimum value timing).
The measurement operation (calculation of biological information) is started from time t2 (minimum value timing).

  As described above, the time t2 is output as the control timing from the timing control unit 13 to the wave height measurement unit 9, the period measurement unit 11, and the biological information calculation unit 13, and according to this timing, as shown in FIG. Wave height data, period data, and biological information are calculated.

c) Next, a procedure (biological information detection method) of processing performed by the biological information detection apparatus will be described. This process is performed every (1 msec), for example.
As shown in FIG. 4, first, in step (S) 100, first-order differentiation of the pulse wave data output from the BPF unit 7 is performed.

In the following step 110, the period counter is incremented (added by 1).
In the following step 120, it is determined whether or not the primary differential value has changed from minus to plus. That is, it is determined whether or not the pulse waveform of the pulse wave data is bottom (minimum value: minimum value timing). If an affirmative determination is made here, the process proceeds to step 130, whereas if a negative determination is made, the process proceeds to step 220.

  In step 220, it is determined whether or not a first-order differential maximum value has been detected. That is, it is determined whether or not a value (= first derivative maximum value: see FIG. 3) at which the first derivative value changes from increasing to decreasing is detected. If an affirmative determination is made here, the process proceeds to step 230, while if a negative determination is made, the process proceeds to step 240.

In step 230, since the first-order differential maximum value is detected, the first-order differential maximum value is stored in the memory, and this process is temporarily terminated.
On the other hand, in step 240, it is determined whether or not the primary differential value has changed from plus to minus. That is, it is determined whether or not the pulse waveform of the pulse wave data has a peak (maximum value: maximum value timing). If an affirmative determination is made here, the process proceeds to step 250, while if a negative determination is made, the process proceeds to step 260.

In step 250, since it is the peak of the pulse wave waveform, the maximum amplitude of the pulse wave at the peak (pulse wave maximum value: VM1 for example) is stored in the memory, and this process is temporarily terminated.
On the other hand, in step 260, it is determined whether or not a first-order differential minimum value has been detected. That is, it is determined whether or not a value (= first derivative minimum value: see FIG. 3) in which the first derivative value changes from decreasing to increasing is detected. If an affirmative determination is made here, the process proceeds to step 270, whereas if a negative determination is made, the process proceeds to step 280.

In step 270, since the first-order differential minimum value is detected, the first-order differential minimum value is stored in the memory, and this process is temporarily terminated.
On the other hand, in step 280, it is determined whether or not the period counter has exceeded 2 seconds. If an affirmative determination is made here, the process proceeds to step 210. If a negative determination is made, the present process is temporarily terminated.

  Here, it is determined whether or not the period counter exceeds 2 seconds. The state where the period exceeds 2 seconds indicates that the pulse rate is less than 30 times (1 minute). It is determined that there is some abnormality. Therefore, in this case, the memory storing the data is cleared in step 210 described later.

  Further, in step 130, which proceeds after an affirmative determination (ie, it is determined that the pulse wave is the minimum value) in step 120, it is determined whether or not the period counter is less than 0.5 seconds. If an affirmative determination is made here, the process proceeds to step 210 to perform similar processing (memory clearing), whereas if a negative determination is made, the process proceeds to step 140.

  Here, it is determined whether or not the period counter is less than 0.5 seconds. If the period counter is less than 0.5 seconds, the pulse rate is 120 times or more (1 minute), and there is some abnormality as data. This is because it is judged that there is.

On the other hand, in step 140, it is determined whether or not the data is the first beat, and if an affirmative determination is made here, the present process is once terminated, whereas if a negative determination is made, the process proceeds to step 150.
Here, the determination of whether or not the data is the first beat is not possible because the start of the pulse wave is often not clearly understood in the case of the first beat data. It is to do.

  In step 150, it is determined whether or not the maximum differential value is smaller than the negative minimum differential value. If an affirmative determination is made here, the present process is temporarily terminated, whereas if a negative determination is made, the process proceeds to step 160.

This determination is for discriminating whether the pulse wave data is data that correctly indicates the peak of the pulse wave, or data that is not the peak of the pulse wave but simply indicates the rising edge.
That is, when the maximum differential value> −the minimum differential value, it is determined to be a bump, and when the maximum differential value <−the minimum differential value, it is determined to be a pulse (a peak indicating a pulse).

  Specifically, when the heart contracts, the pressure in the ventricle decreases, and when the pressure falls below the pressure in the aorta, the aortic valve closes, and the pressure due to the increase in the volume of the aortic base due to the blood flow component in the reverse direction generated at the base of the aorta Due to the decrease in the waveform, a bump (dichroic notch) is generated in the waveform of the pulse wave. As a result, the bumps are generated immediately after the rapid change of the pulse wave, so that the peak value (maximum value) of the bump or pulse wave can be determined by comparing the maximum value and the minimum value of the differential values.

In step 160, the amplitude (VL1, etc.) at the bottom (minimum value), which is the pulse wave minimum value, is measured.
In the subsequent step 170, for example, the pulse wave period T is calculated from the bottom interval, and its reciprocal (1 / T) is calculated.

  In the subsequent step 180, the frequency passband (bandpass frequency) of the variable bandpass filter is set based on the frequency that is the reciprocal of the pulse wave cycle calculated in step 170.

In the following step 190, the wave height is calculated from the pulse wave data. For example, the difference between the peak amplitude (for example, VM1) and the bottom amplitude (for example, VL1) of the pulse wave signal is calculated as the wave height.
In the following step 200, biological information is calculated. That is, the alcohol concentration is calculated from the wave height ratio, and the pulse wave number is calculated from the cycle.

In the following step 210, the maximum differential value, the minimum differential value, the pulse wave maximum value, and the period counter are cleared, and this process is temporarily terminated.
d) As described above, in this embodiment, using the cycle data (cycle) for each beat immediately before being measured by the cycle measuring unit 11, the BPF unit 7 uses the pulse wave frequency (f) that is the reciprocal of this cycle. = 1 / T), and this frequency is set as a passing frequency band for each beat.

  As a result, the function as an optimal pulse wave filter is always followed for each pulse for the pulse rate that varies depending on individual differences and physical condition at each measurement, so a clear pulse wave with less noise such as body movement Data can be calculated.

  Further, in this embodiment, based on the pulse wave data obtained from the BPF unit 7, the timing control unit 13 firstly differentiates the pulse wave data to obtain the maximum timing, the baseline timing, and the minimum timing, Using the control data, the BPF unit 7, the cycle measurement unit 11, the wave height measurement unit 9, and the biological information detection unit 15 are operated in synchronization. That is, for example, in accordance with the minimum value timing, the pulse height measurement unit 9 measures the pulse wave height data for each pulse, and the cycle measurement unit 11 measures the pulse wave cycle data for each pulse. The biometric information data is calculated for each pulse using these data.

  By configuring in this way, it is possible to always maintain clear pulse wave data without noise, so that stable control data can be generated, highly accurate periodic data and pulse height data can be measured for each pulse, Biometric data can be detected immediately.

Therefore, in this embodiment, there is a remarkable effect that both measurement time can be shortened and highly accurate biological information measurement can be achieved.
In the present embodiment, as shown in FIG. 5, when the period of a certain pulse wave cannot be detected, a variable bandpass is made using the period and frequency detected one beat before that. What is necessary is just to set the pass frequency band of a filter.

  Further, in this embodiment, when the initial value after starting the apparatus and continuous measurement cannot be performed (for example, 10 seconds or more), the pass frequency band of the BPF unit 7 is forcibly set to 1 Hz (equivalent to a pulse 60). . This is because this device handles the frequency band of 30 to 120 pulses, that is, 0.5 Hz to 2 Hz, so that it is possible to detect the pulse for all frequency bands by initializing to an intermediate frequency of 1 Hz. It is to do.

  Furthermore, as the variable bandpass filter used in the BPF unit 7 of the present embodiment, a known comb filter having a pass frequency band that is an integral multiple of the fundamental frequency fc can be employed as shown in FIG. In addition, for example, a plurality of bandpass filters (bandpass filters having a pass frequency band that is an integral multiple of the fundamental frequency fc) connected in parallel can be used. Alternatively, a desired pass frequency band may be set by combining a low-pass filter and a high-pass filter.

Next, the second embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
In this embodiment, the present invention is applied to optical pulse wave measurement of a plurality of wavelengths in order to detect alcohol concentration in blood.

a) First, the system configuration of the biological information detection apparatus of this embodiment will be described.
As shown in FIG. 7, in this embodiment, the pulse wave sensor 21 includes a first detection unit 21 a that receives and receives light of a first wavelength (Anm: for example, 1300 nm), and a second wavelength (Bnm). : For example, 1650 nm) is used, and a sensor provided with the first detection unit 21a that receives the light is used.

  And corresponding to the 1st detection part 21a, while being provided with the 1st pulse wave numerical value conversion part 23, the 2nd pulse wave numerical value conversion part 25 is provided with respect to the 2nd detection part 21b, and also 1st The pulse wave numerical value conversion unit 23 and the second pulse wave numerical value conversion unit 25 are provided with a calculation unit 27 having a known microcomputer as a main part for processing data A / D converted.

  The calculation unit 27 corresponds to the first pulse wave number conversion unit 23 and functionally executes the pulse wave data from the first pulse wave number conversion unit 23 as shown in FIG. Similar to Example 1, a BPF unit 29 that is a variable bandpass filter that passes only a signal in a frequency band corresponding to a pulse wave, a wave height measurement unit 31 that obtains wave height data, a period measurement unit 33 that obtains period data, A timing control unit 35 for calculating calculation timing is provided.

  Further, in order to process the pulse wave data from the second pulse wave number conversion unit 25 in correspondence with the second pulse wave number conversion unit 25, the calculation unit 27 outputs only a signal in a frequency band corresponding to the pulse wave. A BPF unit 37 which is a variable bandpass filter to be passed, a wave height measuring unit 39 for obtaining wave height data, and a timing control unit 43 for calculating calculation timing are provided.

  Further, the calculation unit 27 inputs the wave height data from both the wave height measurement units 31 and 39 and the period data from the period measurement unit 33, and detects blood alcohol concentration detection, which is a biological information detection unit that detects biological information. Part 45.

  In the arithmetic unit 27, as in the first embodiment, the pulse wave data output from the BPF unit 29 is, as shown by the solid line in the figure, the wave height measuring unit 31, the period measuring unit 33, and the timing control. The period data output to the unit 35 and measured by the period measurement unit 33 (immediately before every beat) is the pass frequency band of the variable bandpass filter for each beat with respect to both BPF units 29 and 37. Used for setting.

The pulse wave data output from the BPF unit 37 is output to the wave height measurement unit 39 and the timing control unit 43.
Each of the BPF units 29 and 37 calculates a frequency from cycle data (cycle) and sets this frequency as a pass frequency band.

  Further, as indicated by a broken line in the figure, control timing data output from the timing control unit 35 is output to the BPF unit 29, the wave height measurement unit 31, the cycle measurement unit 33, and the blood alcohol concentration detection unit 45. . Similarly, control timing data output from the timing control unit 43 is output to the BPF unit 37, the wave height measurement unit 39, the cycle measurement unit 33, and the blood alcohol concentration detection unit 45.

b) Next, signal processing performed in the biological information detection apparatus will be described.
As shown in FIG. 8, the human body pulse wave signals corresponding to the respective wavelengths obtained from the pulse wave sensor 21 are converted into A / A by the first pulse wave value conversion unit 23 and the second pulse wave value conversion unit 25, respectively. D-converted and filtered by the BPF units 29 and 37 to obtain each pulse wave data. That is, wavelength Anm pulse wave data and wavelength Bnm pulse wave data are obtained.

  In each pulse wave data, control data (maximum value timing data) corresponding to the peak of the pulse wave and control data (minimum value timing data) corresponding to the bottom are obtained.

  Here, when the light emitting elements having a plurality of wavelengths are used for the wavelength Anm pulse wave data and the wavelength Bnm pulse wave data, a control timing shift (minimum value timing shift) occurs. Cycle data and blood alcohol concentration are calculated at the latest timing.

That is, at a certain (slowest) minimum value timing, the period (the reciprocal thereof) and blood alcohol concentration are calculated based on the pulse wave data immediately before (one beat before).
Here, as shown in FIG. 9, the blood alcohol concentration is proportional to the wavelength ratio of the two types of light, and this wavelength ratio depends on the ratio (wave height ratio) of the wave height data of the wavelength Anm to the wave height data of the wavelength Bnm. Can be sought. The pulse rate can be obtained by calculating “60 / period of wavelength An”.

  In addition, when the deviation (error) of the control timing of the wavelength Anm pulse wave data and the wavelength Bnm pulse wave data is large, for example, when it exceeds 20% of the cycle, an abnormality occurs in fixing the pulse wave sensor 21. Since there is a high possibility that the pulse wave could not be detected normally due to the influence, in this case, the processing based on the pulse wave data is not performed.

  In this embodiment, one period measurement unit 33 is provided, and the period measurement is performed at the first wavelength among which a plurality of wavelengths are most easily measured, and the pass frequencies of all the BPF units 29 and 37 are measured. Bands are set at the same frequency. Note that the cycle measurement unit 33 determines whether the cycle data is acceptable or not based on the shift of the control timing in the timing control units 35 and 43.

c) Next, a procedure (biological information detection method) of processing performed by the biological information detection apparatus will be described.
As shown in FIG. 10, first, in step 300, the human body pulse wave signal obtained by the light of the first wavelength is filtered to obtain pulse wave data. At this time, as in the first embodiment, the control timing is synchronized, and the frequency obtained from the cycle data (cycle) is set as the pass frequency band of the BPF units 29 and 37 for each beat.

In the subsequent step 310, the wave height based on the first wavelength is calculated from the pulse wave data obtained in step 300.
In subsequent step 320, the human body pulse wave signal obtained by the light of the second wavelength is filtered to obtain pulse wave data. At this time, the control timing is synchronized as described above.

In the subsequent step 330, the wave height based on the second wavelength is calculated from the pulse wave data obtained in step 320.
In the following step 340, as shown in FIG. 9, the ratio (wave height ratio) between the wave height by the first wavelength and the wave height by the second wavelength is calculated.

  In subsequent step 350, it is determined whether or not the wave height ratio has changed from the reference ratio. If an affirmative determination is made here, the process proceeds to step 360, while if a negative determination is made, the process proceeds to step 380. The reference ratio is the wave height ratio when the blood alcohol concentration is zero.

  In step 360, the crest ratio is applied to a calibration curve to calculate the blood alcohol concentration. Since the calibration curve between the crest ratio and the blood alcohol concentration is stored for each subject, the blood alcohol concentration can be obtained by applying the crest ratio to the calibration curve.

In the subsequent step 370, the blood alcohol concentration is displayed on a display or the like, and the present process is temporarily terminated.
On the other hand, in step 380, it is determined that there is no drinking, and this processing is once ended.

Therefore, this embodiment also has the same effect as the first embodiment.
In this embodiment, an example in which light of two wavelengths is used has been described. However, measurement may be performed using light of three wavelengths (870 nm, 945 nm, 1300 nm), for example. In this case, since the pulse waveform is most easily measured at the wavelength of 870 nm, the pass frequency band of the three-wavelength BPF portion is set using periodic data of light having the wavelength of 870 nm.

Next, the third embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
In the first and second embodiments, calculation of wave height data, calculation of period data, calculation of biological information is performed for each beat, and the frequency obtained from the immediately preceding period data (period) is set to the pass frequency band of the BPF unit. However, in this embodiment, the same calculation (wave height calculation and cycle) as that performed for each beat in the first embodiment every multiple beats (for example, every 2 beats or 3 beats immediately before). Calculation).

  And when processing data for every several beats, it is desirable to perform stabilization processing, such as a moving average, for example. For example, when the cycle T1 is obtained on the first beat and the cycle T2 is obtained on the second beat, when processing data every two beats, the cycle for one beat in the period of the two beats is: A method of averaging such as (T1 + T2) / 2 is conceivable.

Specific examples will be described below.
As shown in FIG. 11, for example, for the calculation of the first wave at the start of measurement, the cycle 1s (corresponding to the pulse 60) is forcibly used as a seed, and the second wave is not the average value but the immediately preceding one wave. Period data (for example, period T1) is used, and an average value (for example, period (T1 + T2) / 2) of the immediately preceding two data (for example, period T1 + period T2) is used for the third wave. For the fourth and subsequent waves, the moving average of the previous two data is used.

When there is a measurement error, the moving average is calculated without using the measurement error data (for example, using data immediately before the measurement error).
Also, as shown in FIG. 12, for example, for the calculation of the first wave at the start of measurement, the period 1s (equivalent to pulse 60) is forcibly used as a seed, and the second wave is not the average value but the immediately preceding one wave. Minute period data (for example, period T1), the third wave uses the average (for example, period (T1 + T2) / 2) of the last two data (first and second waves), and the fourth wave The eye uses the average (for example, period (T1 + T2 + T3) / 3) of the last three data (three data of the first wave, the second wave, and the third wave). The average (for example, period (T1 + T2 + T3 + T4) / 4) of the 4th data of the 1st wave, the 2nd wave, the 3rd wave, and the 4th wave is used. Then, after the sixth wave, the moving average of the previous four data is used.

When there is a measurement error, the moving average is calculated without using the measurement error data (for example, using data immediately before the measurement error).
Also in this embodiment, the measurement accuracy is high, and the data can be processed more quickly than in the case of the conventional Fourier transform.

Moreover, the process which sets the frequency obtained from period data (period) to the passing frequency band of a BPF part may be performed for every beat, and may be performed for every two or more beats.
Needless to say, the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 21 ... Pulse wave sensor 3, 23, 25 ... Pulse wave numerical value conversion part 5, 27 ... Calculation part 7, 29, 37 ... BPF part 9, 31, 39 ... Wave height measurement part 11, 33 ... Period measurement part 13, 35, 43 ... Timing control unit 15 ... Biological information detection unit 45 ... Blood alcohol concentration detection unit

Claims (11)

A filter unit in which the pass frequency band is variable and a pulse wave signal obtained from a living body is input;
Based on the pulse wave data output from the filter unit, a period measuring unit that measures period data of the pulse wave signal;
A biological information detection apparatus comprising:
Based on the pulse wave data obtained from the immediately preceding pulse wave signal, the basic frequency of the pulse wave signal is calculated from the period data calculated by the period measuring unit, and based on the basic frequency for each beat. The biological information measuring device is characterized in that a pass frequency band of the filter unit is set. A filter unit in which the pass frequency band is variable and a pulse wave signal obtained from a living body is input;
Based on the pulse wave data output from the filter unit, a period measuring unit that measures period data of the pulse wave signal;
Based on the pulse wave data output from the filter unit, a pulse height measuring unit that measures the pulse height of the pulse wave signal;
Biological information indicating the state of the living body is calculated using at least one of the period data of the pulse wave signal measured by the period measurement unit and the wave height data of the pulse wave signal measured by the wave height measurement unit. A biological information calculation unit;
A biological information detection apparatus comprising:
Based on the pulse wave data obtained from the immediately preceding pulse wave signal, the basic frequency of the pulse wave signal is calculated from the period data calculated by the period measuring unit, and based on the basic frequency for each beat. The biological information measuring device is characterized in that a pass frequency band of the filter unit is set.   The pulse wave data is first-order differentiated, and the calculation result is calculated using the calculation timing of the filter unit, the cycle measurement unit, the wave height calculation unit, and the biological information calculation unit. The biological information measuring device according to claim 2, wherein the biological information measuring device is used for setting.   When simultaneous measurement of the pulse wave of the living body using light of a plurality of wavelengths by an optical sensor, the timing of pulse wave data corresponding to the plurality of wavelengths output from the filter unit is compared. The biological information detection apparatus according to claim 1, wherein a detection error of the biological information is determined.   Instead of the pulse wave data corresponding to the pulse rate of 1 beat, using the pulse wave data corresponding to the pulse rate of 2 beats or more, averaged cycle data corresponding to 1 beat is calculated (for example, 1 beat The biological information detection apparatus according to claim 1, wherein a pass frequency band of the filter unit is set based on the averaged periodic data.   The biological information detection according to any one of claims 1 to 5, wherein at least one of a comb filter, a plurality of band pass filters, a high pass filter, and a low pass filter is used as the filter unit. apparatus. A measurement step of obtaining pulse wave data by filtering a pulse wave signal obtained from a living body using a filter unit having a variable pass frequency band, and measuring period data of the pulse wave signal based on the pulse wave data A biological information detection method comprising:
The basic frequency of the pulse wave signal is calculated from the period data based on the pulse wave data obtained from the previous pulse wave signal, and the pass frequency of the filter unit is calculated based on the basic frequency for each beat. A biological information measuring method characterized by setting a band. Using a filter unit having a variable pass frequency band, the pulse wave signal obtained from the living body is filtered to obtain pulse wave data, and the period data of the pulse wave signal is measured based on the pulse wave data. A measurement step of measuring the pulse height of the pulse wave signal;
Biological information indicating the state of the living body is calculated using at least one of the period data of the pulse wave signal measured by the period measurement unit and the wave height data of the pulse wave signal measured by the wave height measurement unit. A biological information calculation process;
A biological information detection method comprising:
Based on the pulse wave data obtained from the immediately preceding pulse wave signal, the basic frequency of the pulse wave signal is calculated from the period data calculated by the period measuring unit, and based on the basic frequency for each beat. And setting a pass frequency band of the filter unit.   The pulse wave data is first-order differentiated, and the calculation result is calculated using the calculation timing of pulse wave data in the filter unit, calculation of the period measurement, calculation of the wave height, and calculation of the biological information. The biological information measuring method according to claim 8, wherein the biological information measuring method is used for setting.   When simultaneous measurement of the pulse wave of the living body using light of a plurality of wavelengths by an optical sensor, the timing of pulse wave data corresponding to the plurality of wavelengths output from the filter unit is compared. The biological information detection method according to claim 7, wherein a detection error of the biological information is determined.   Instead of the pulse wave data corresponding to the pulse rate of one beat, using the pulse wave data corresponding to the pulse rate of two or more beats, averaged cycle data corresponding to one beat is calculated, and the averaged cycle The biological information detection method according to claim 7, wherein a pass frequency band of the filter unit is set based on data.

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