JP2013172763A - Pulsation detecting device, electronic apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulsation detecting device for detecting noise of a pulsation sensor signal by a small calculation amount and power consumption, and to provide an electronic apparatus, a program, and the like.SOLUTION: A pulsation detecting device 100 includes: a signal processing unit 110 that processes a signal from a pulsation detecting unit 10 having a pulsation sensor 11 for outputting a pulsation sensor signal; and a pulsation information operation unit 120 that calculates pulsation information on the basis of a pulsation detection signal that is the pulsation sensor signal after cutting DC components. The signal processing unit 110 has a noise detecting part 1111 that detects noise of the pulsation sensor signal on the basis of differential information between a first-timing signal value and a second-timing signal value of the pulsation sensor signal before cutting the DC components. The pulsation information operation unit 120 calculates the pulsation information on the basis of the noise detection result of the noise detecting part 1111.

Description

  The present invention relates to a pulsation detection device, an electronic device, a program, and the like.

  Conventionally, electronic devices including a pulsation detecting device such as a pulse meter have been widely used. The pulsation detection device is a device for detecting pulsation derived from the heartbeat of the human body, for example, based on a signal from a pulse wave sensor attached to an arm, palm, finger, etc. It is an apparatus for detecting a signal to be detected.

  For example, a photoelectric sensor is used as the pulse wave sensor. In this case, a method of detecting reflected light or transmitted light of the light irradiated on the living body with the photoelectric sensor can be considered. Depending on the blood flow in the blood vessel, the amount of light absorbed and reflected by the living body differs, so the sensor information (pulse wave sensor signal) detected by the photoelectric sensor is a signal corresponding to the blood flow, etc. By analyzing the signal, it is possible to obtain information on the beat.

  However, various noises may be mixed in the pulse wave sensor signal. For example, in addition to reflected light, external light such as sunlight or indoor lighting may enter, and noise (body motion noise) generated due to the influence of the body motion of the human body may be mixed. Therefore, instead of using the pulse wave sensor signal as it is for detecting the pulsation signal, a technique is widely used in which noise reduction processing for reducing body movement noise and the like is performed.

JP-A-10-258040

  As described above, in the pulsation detection device, it is assumed that various noises are mixed in the pulse wave sensor signal from the pulse wave sensor (or the pulse wave detection signal acquired therefrom). Therefore, if noise reduction processing for reducing body movement noise or the like is not performed, noise is directly mixed in the beat information, and the value of the beat information accurately represents the actual beat of the wearer. There is no possibility. In this case, if the pulsation information is simply output, the user's judgment based on the pulsation information may be mistaken. Therefore, there is an advantage of knowing the reliability of the detected pulsation information by calculating the SN state indicating the degree of noise mixing in the signal (pulse wave sensor signal or pulse wave detection signal) used for calculating the pulsation information. large.

  Even if some noise reduction processing is performed, since it is difficult to completely remove noise by the noise reduction processing, the SN state is calculated and the reliability of the detected pulsation information is known. Is desirable.

  Patent Document 1 discloses an SN state detection method for determining whether at least one of a pulse wave signal and a body motion signal (corresponding to sensor information from a body motion sensor) includes a noise component exceeding a predetermined value. Yes.

  However, since Patent Document 1 uses frequency analysis (for example, FFT) to determine the SN state, the amount of calculation increases and power consumption also increases compared to the case where frequency analysis is not performed.

  As a technique for reducing the amount of calculation and power consumption, it is conceivable to use a time-varying waveform of a pulse wave detection signal (for example, a signal component after applying HPF to a pulse wave sensor signal) as it is. For example, if the degree of noise mixing can be obtained based on the amplitude information of the pulse wave detection signal, the amount of calculation can be reduced compared to the case of using FFT. However, the amplitude of the pulse wave detection signal increases when the signal derived from the heartbeat that should be detected increases, and also increases when the amount of noise mixed in increases. is there.

  According to some aspects of the present invention, it is possible to provide a pulsation detection device, an electronic device, a program, and the like that perform noise detection of a pulse wave sensor signal with a small amount of calculation and power consumption.

  One aspect of the present invention is a signal processing unit that performs processing on a signal from a pulse wave detection unit that includes a pulse wave sensor that outputs a pulse wave sensor signal, and the pulse wave sensor signal after the DC component cut. A pulsation information calculation unit that calculates pulsation information based on the wave detection signal, and the signal processing unit includes a signal value at a first timing of the pulse wave sensor signal before the DC component cut, A noise detection unit configured to detect noise of the pulse wave sensor signal based on difference information from the signal value of the pulse wave sensor signal before the DC component cut at a second timing different from the first timing; The pulsation information calculation unit relates to a pulsation detection device that calculates the pulsation information based on the detection result of the noise in the noise detection unit.

  In one aspect of the present invention, when the pulsation information is calculated based on the pulse wave sensor signal after the DC component cut, the result of the noise detection performed based on the difference information of the pulse wave sensor signal before the DC component cut. Is used. This makes it possible to reduce the amount of calculation and power consumption compared to a noise detection method that performs frequency analysis.

  In one aspect of the present invention, the noise detection unit acquires a difference value between the signal value at the first timing and the signal value at the second timing as the difference information, and the difference value The noise may be detected based on the result of the comparison process with a given threshold value.

  Thereby, it becomes possible to use a difference value as difference information.

  In the aspect of the invention, the noise detection unit may compare the pulse wave before the DC component cut by comparing the signal value at the first timing with the signal value at the second timing. The signal value change direction of the sensor signal may be acquired as the difference information, and it may be determined that the noise is detected when the signal value change direction is the same direction in a given period.

  As a result, the signal value change direction can be used as the difference information.

  In the aspect of the invention, the noise detection unit acquires a difference value between the signal value at the first timing and the signal value at the second timing as the difference information, and the difference value is When it is greater than a given threshold, it is determined that the noise has been detected, and even when the difference value is less than or equal to the given threshold, the sign of the difference value is the same code in a given period In such a case, it may be determined that the noise has been detected.

  As a result, both the difference value and the sign of the difference value can be used as the difference information.

  In the aspect of the invention, the noise detection unit may determine whether or not the noise is detected in the given period set according to the length of the pulsation cycle.

  Thereby, when using a signal value change direction as difference information, it becomes possible to make the period used as a candidate for detection processing into a period based on the length of a pulsation cycle.

  In the aspect of the invention, the signal processing unit may detect the pulse wave in a noise detection period set based on a noise detection timing that is a timing at which the noise detection unit determines that the noise is detected. A waveform shaping unit that performs waveform shaping processing of the signal, wherein the pulsation information calculation unit may calculate the pulsation information based on the pulse wave detection signal after the waveform shaping processing by the waveform shaping unit. Good.

  Thereby, when noise is detected, it becomes possible to perform waveform shaping processing on the pulse wave detection signal in the noise detection period.

  In the aspect of the invention, the waveform shaping unit may perform a process of reducing the amplitude of the pulse wave detection signal in the noise detection period as the waveform shaping process.

  This makes it possible to perform the process of reducing the amplitude as the waveform shaping process.

  In the aspect of the invention, the waveform shaping unit may perform a process of replacing the pulse wave detection signal in the noise detection period with another signal as the waveform shaping process.

  This makes it possible to perform processing for replacing the pulse wave detection signal in the noise detection period with another signal as waveform shaping processing.

  In one aspect of the present invention, the waveform shaping unit performs the waveform shaping processing of the pulse wave detection signal in the noise detection period determined by a start timing and an end timing set based on the noise detection timing. You may go.

  Accordingly, it is possible to set the start timing and end timing of the noise detection period based on the noise detection timing.

  In the aspect of the invention, the noise detection unit may detect that the noise is detected based on the difference information when the value of the body motion detection signal from the body motion sensor is larger than a given threshold value. Even when it is determined, it may be determined that the noise is not detected.

  This makes it possible to use a body movement detection signal for noise detection processing.

  In another aspect of the present invention, the pulse wave detection unit described above, the pulse wave sensor, the pulse wave detection unit that outputs a signal based on the pulse wave sensor signal from the pulse wave sensor, And the pulse wave detection unit outputs the pulse wave sensor signal before the high-pass filter processing to the noise detection unit as the pulse wave sensor signal before the DC component cut, and the pulse wave sensor signal after the high-pass filter processing. The present invention relates to an electronic device that outputs a wave sensor signal as the pulse wave detection signal that is the pulse wave sensor signal after the DC component cut.

  According to another aspect of the present invention, there is provided a signal processing unit for processing a signal from a pulse wave detection unit having a pulse wave sensor that outputs a pulse wave sensor signal, and the pulse wave sensor signal after the DC component is cut. Based on the pulse wave detection signal, the computer functions as a pulsation information calculation unit that calculates pulsation information, and the signal processing unit performs the first timing of the pulse wave sensor signal before the DC component cut. And the noise of the pulse wave sensor signal is detected based on difference information between the signal value of the pulse wave sensor signal before the DC component cut at a second timing different from the first timing. The pulsation information calculation unit includes a noise detection unit, and is related to a program for calculating the pulsation information based on a detection result of the noise in the noise detection unit.

The basic structural example of the electronic device containing the pulsation detection apparatus of this embodiment. The structural example of the body movement noise reduction part using an adaptive filter. 3A to 3C show examples of a pulse wave detection signal, a body motion detection signal, and a waveform and a frequency spectrum of a signal after body motion noise reduction processing based on the pulse wave detection signal and the body motion detection signal. 4A and 4B are examples of electronic devices including a pulsation detection device. The detailed structural example of the electronic device containing the pulsation detection apparatus of this embodiment. An example of noise detection based on a noise detection signal. 7A and 7B show examples of waveforms and frequency spectra before and after the waveform shaping process. The flowchart explaining the process of this embodiment. The other flowchart explaining the process of this embodiment. An example of setting a noise detection period based on noise detection timing.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. Configuration Example of Electronic Device Including Pulsation Detection Device First, a basic configuration example of an electronic device (pulse meter in a narrow sense) including a pulsation detection device and a pulsation detection device of this embodiment will be described with reference to FIG. To do. FIG. 1 shows an example of a pulsation detection device and an electronic device, and the configuration included in the pulsation detection device and the like of this embodiment may be simplified or omitted. In some cases, the pulsation detection device or the like includes an indispensable component.

  As shown in FIG. 1, the pulsometer that is an example of the electronic apparatus of the present embodiment includes a pulse wave detection unit 10, a body motion detection unit 20, a pulsation detection device 100, and a display unit 70. However, the electronic apparatus is not limited to the configuration shown in FIG. 1, and various modifications such as omission / change of some of these components or addition of other components are possible.

  The pulse wave detection unit 10 outputs a signal based on sensor information (pulse wave sensor signal) of the pulse wave sensor. The pulse wave detection unit 10 can include, for example, a pulse wave sensor 11, a filter processing unit 15, and an A / D conversion unit 16. However, the pulse wave detection unit 10 is not limited to the configuration of FIG. 1, and various components such as omitting some of these components or adding other components (for example, an amplification unit that amplifies a signal, etc.) are included. Variations are possible.

  The pulse wave sensor 11 is a sensor for detecting a pulse wave signal. For example, a photoelectric sensor can be considered. In addition, when using a photoelectric sensor as the pulse wave sensor 11, you may use the sensor comprised so that the signal component of external lights, such as sunlight, may be cut. This can be realized by, for example, a configuration in which a plurality of photodiodes are provided and difference information is obtained by feedback processing using these signals.

  The pulse wave sensor 11 is not limited to a photoelectric sensor, and may be a sensor using ultrasonic waves. In this case, the pulse wave sensor 11 has two piezoelectric elements. One of the piezoelectric elements is excited to transmit an ultrasonic wave into the living body, and the ultrasonic wave reflected by the blood flow of the living body is transmitted to the other. Received by the piezoelectric element. Since the frequency change occurs in the transmitted ultrasound and the received ultrasound due to the Doppler effect of blood flow, a signal corresponding to the blood flow can be obtained in this case as well, and pulsation information can be estimated. . Other sensors may be used as the pulse wave sensor 11.

  The filter processing unit 15 performs high-pass filter processing on the sensor information from the pulse wave sensor 11. Note that the cutoff frequency of the high-pass filter may be obtained from a typical pulse rate. For example, there are very few cases where the pulse rate of a normal person falls below 30 times per minute. In other words, since the frequency of the signal derived from the heartbeat is rarely 0.5 Hz or less, even if the information of the frequency band in this range is cut, the adverse effect on the signal to be acquired should be small. Therefore, about 0.5 Hz may be set as the cutoff frequency. Further, depending on the situation, a different cutoff frequency such as 1 Hz may be set. Furthermore, since it is possible to assume a typical upper limit value for the human pulse rate, the filter processing unit 15 may perform bandpass filter processing instead of high-pass filter processing. The cutoff frequency on the high frequency side can be set freely to some extent, but a value such as 4 Hz may be used.

  The A / D converter 16 performs A / D conversion processing and outputs a digital signal. The process in the filter processing unit 15 described above may be an analog filter process performed before the A / D conversion process, or a digital filter process performed after the A / D conversion process. .

  The body motion detection unit 20 outputs a signal (body motion detection signal) corresponding to the body motion based on the sensor information of various sensors. The body motion detection unit 20 can include, for example, an acceleration sensor 21, a pressure sensor 22, and an A / D conversion unit 26. However, the body motion detection unit 20 may include other sensors (for example, a gyro sensor), an amplification unit that amplifies a signal, and the like. Further, it is not necessary to provide a plurality of types of sensors, and a configuration including one type of sensor may be used.

  The pulsation detection device 100 includes a signal processing unit 110 and a pulsation information calculation unit 120. However, the pulsation detecting device 100 is not limited to the configuration in FIG. 1, and various modifications such as omitting some of these components or adding other components are possible. The signal processing unit 110 performs signal processing on the output signal from the pulse wave detection unit and the output signal from the body motion detection unit.

  The signal processing unit 110 can include a pulse wave signal processing unit 111, a body motion signal processing unit 113, and a body motion noise reduction unit 115.

  The pulse wave signal processing unit 111 performs some signal processing on the signal from the pulse wave detection unit 10. Note that various signals based on the pulse wave sensor signal can be considered as the output from the pulse wave detector 10 indicated by D1 in FIG. For example, since calculation of pulsation information described later is often performed based on a pulse wave sensor signal (pulse wave detection signal) after the DC component cut, D1 includes a pulse wave sensor signal after high-pass filter processing. It is assumed that However, a signal that has not been subjected to filter processing may be output, or a pulse wave sensor signal after low-pass filter processing may be output depending on circumstances. When D1 includes a plurality of signals (for example, both the pulse wave sensor signal before the high-pass filter processing and the pulse wave sensor signal after the processing), the processing in the pulse wave signal processing unit 111 is included in D1. It may be performed for all of the signals, or may be performed for some of the signals. Various processing contents are also conceivable. For example, an equalizer process for the pulse wave detection signal may be performed, or another process may be performed.

  The body motion signal processing unit 113 performs various signal processes on the body motion detection signal from the body motion detection unit 20. Similar to D1, various signals can be considered as the output from the body motion detection unit 20 indicated by D2. For example, since the example of FIG. 1 includes the acceleration sensor 21 and the pressure sensor 22, the body motion detection signal of D2 includes an acceleration signal and a pressure signal. Since the body motion detection sensor may be another sensor such as a gyro sensor, D2 includes an output signal of a type corresponding to the type of sensor. The processing in the body motion signal processing unit 113 may be performed on all or part of the signals included in D2. For example, the signal included in D2 may be compared to perform a process of determining a signal used in the noise reduction process in the body motion noise reduction unit 115.

  In the processing in the pulse wave signal processing unit 111, a body motion detection signal may be used in accordance with the signal from the pulse wave detection unit. Similarly, in the processing in the body motion signal processing unit 113, a signal from the pulse wave detection unit 10 may be used in accordance with the body motion detection signal. In addition, a signal after a given process is performed in the pulse wave signal processing unit 111 on the output signal from the pulse wave detection unit 10 may be used for processing in the body motion signal processing unit 113. Or vice versa.

  The body motion noise reduction unit 115 performs a process of reducing noise (body motion noise) caused by body motion from the pulse wave detection signal using the body motion detection signal. A specific example of noise reduction processing using an adaptive filter is shown in FIG. The pulse wave sensor signal acquired from the pulse wave sensor 11 includes a component due to body movement in addition to a component due to heartbeat. The same applies to the pulse wave detection signal (pulse wave sensor signal after the DC component cut) used for the calculation of pulsation information. Of these, components useful for the calculation of pulsation information are components caused by heartbeats, and components caused by body movements hinder the calculation. Therefore, the body motion noise included in the pulse wave detection signal is obtained by obtaining a signal (body motion detection signal) due to body motion using the body motion sensor and taking the difference between the pulse wave detection signal and the body motion detection signal. Reduce. However, even if the body motion noise in the pulse wave detection signal and the body motion detection signal from the body motion sensor are signals resulting from the same body motion, the signal level is not necessarily the same. Therefore, a filter process in which a filter coefficient is adaptively determined is performed on the body motion detection signal, and the difference between the body motion detection signal after the filter process and the pulse wave detection signal is taken.

  FIGS. 3A to 3C illustrate the above processing in terms of a frequency spectrum. FIG. 3A and the like show the time-varying waveform of the signal at the top and the frequency spectrum at the bottom. FIG. 3A shows a pulse wave detection signal before body motion noise reduction, and as shown in A1 and A2, two frequencies having large values appear in the spectrum. One of these is caused by heartbeat, and the other is caused by body movement. Note that although there are some frequencies that are higher than A1, they are not considered here because they are high frequency components corresponding to integer multiples of A1 and A2. Hereinafter, high-frequency components are also seen in FIGS. 3B and 3C, but are not considered here as well.

  On the other hand, FIG. 3B shows a body motion detection signal. If there is only one type of body motion that has caused the body motion detection signal, a frequency having a large value as shown in B1 is obtained. One appears. Here, the frequency of B1 corresponds to A2 in FIG. In such a case, the signal shown in FIG. 3C is obtained by taking the difference between the pulse wave detection signal and the body motion detection signal by the method shown in FIG. As is apparent from the figure, the pulse wave detection signal is obtained by subtracting the body motion detection signal having the peak B1 caused by the body motion from the pulse wave detection signal having the two peaks A1 and A2 caused by the heartbeat and the body motion. The body motion component (corresponding to A2) is removed, and as a result, the peak C1 (frequency corresponds to A1) due to the heartbeat remains.

  It is guaranteed that the body motion noise included in the pulse wave detection signal corresponds to the body motion detection signal, and that the body motion detection signal does not contain a signal component that adversely affects the noise reduction processing. In such a situation, since it is not necessary to perform frequency analysis in the body motion noise reduction unit 115, the frequency spectrum shown in the lower part of FIGS. 3 (A) and 3 (B) may not be considered. However, depending on the type of sensor used to acquire the body motion detection signal, there may be a case where the above condition is not satisfied. In that case, for example, the body motion signal processing unit 113 may process the body motion detection signal so as to satisfy the above condition, or a body motion detection signal that does not satisfy the above condition may be processed. Etc. may be excluded from the output. Various methods for determining whether or not the above conditions are satisfied are conceivable. For example, a frequency spectrum obtained by frequency analysis as shown in the lower part of FIGS. 3A and 3B is used. May be.

  The pulsation information calculation unit 120 calculates pulsation information based on the input signal. The pulsation information may be a pulse rate value, for example. For example, the pulsation information calculation unit 120 obtains a spectrum by performing frequency analysis such as FFT on the pulse wave detection signal after the noise reduction processing in the body motion noise reduction unit 115 and obtains a representative frequency in the obtained spectrum. The processing may be performed with the heartbeat frequency as. In that case, a value obtained by multiplying the obtained frequency by 60 is a commonly used pulse rate (heart rate).

  Note that the pulsation information is not limited to the pulse rate, and may be, for example, information indicating the pulse rate (heartbeat frequency, cycle, etc.). Moreover, the information which represents the state of pulsation may be sufficient, for example, the value showing blood flow itself (or its fluctuation | variation) is good also as pulsation information. However, since the relationship between the blood flow rate and the signal value of the pulse wave sensor signal has individual differences for each user, when the blood flow rate or the like is used as pulsation information, correction processing is performed to deal with the individual differences. It is desirable.

  Also, it detects the timing at which a given value (upper peak, lower peak, or a value above a given threshold) appears on the time-varying waveform of the input pulse wave detection signal, and corresponds to the timing interval. The pulsation information may be calculated by obtaining the heartbeat period from the time to be performed. Alternatively, the pulsation information can be calculated by transforming the waveform of the pulse wave detection signal into a rectangular wave and using the rising edge of the rectangular wave. In this case, it is not necessary to perform frequency analysis, which is advantageous in terms of calculation amount and power consumption. However, in this method, since the signal value is used as it is without being converted to the frequency axis, it is necessary to prepare the waveform to some extent. Therefore, it is desirable to perform frequency analysis in a noisy situation or the like.

  The display unit 70 (output unit in a broad sense) is for displaying various display screens used for presenting the calculated pulsation information, and can be realized by, for example, a liquid crystal display or an organic EL display.

  Specific examples in the case where the above-described electronic device is a pulse meter are shown in FIGS. 4 (A) and 4 (B). FIG. 4A shows an example of a wristwatch-type pulse meter. The base unit 400 including the pulse wave sensor 11 and the display unit 70 is attached to the left wrist 200 of the subject (user) by a holding mechanism 300 (for example, a band). FIG. 4B shows an example of a finger wearing type. A pulse wave sensor 11 is provided at the bottom of a ring-shaped guide 302 for insertion into the fingertip of the subject. However, in the case of FIG. 4B, since there is no space to provide the display unit 70, the display unit 70 (and a device corresponding to the pulsation detecting device 100 if necessary) may be provided elsewhere. is assumed.

  Although the method of the present embodiment to be described later can be applied to any type of electronic device, it is more preferable to apply the method to a wristwatch-type pulsometer (example in FIG. 4A). However, in the example of FIG. 4A, the pulse wave sensor 11 is attached to a portion where it is difficult to acquire a pulse wave sensor signal, such as the outside of the wrist (a portion in contact with the back cover surface of the wristwatch). For this reason, the amplitude of the pulse wave sensor signal output from the pulse wave sensor 11 tends to decrease as a whole. Therefore, it is desirable to perform processing related to accuracy of pulsation information by some method as in the present embodiment described later.

2. Next, the method of this embodiment will be described. As described above, in an electronic device using the pulse wave sensor 11 (pulse meter in a narrow sense), there is a high possibility that noise will be mixed in the pulse wave sensor signal, so the degree of mixing (hereinafter also referred to as SN state) is detected. It is desirable to do. When the degree of mixing is large (the SN state is bad), it is assumed that the reliability of the signal itself or pulsation information calculated based on the signal is low. Therefore, when the SN state is bad, it is possible to call attention to handling of the output beat information by notifying the user of that fact. In this case, information with low reliability is output as it is, and the selection is left to the user. However, the processing may be performed on the side of the pulsation detection device. For example, when the reliability of the pulse wave detection signal or the pulse wave sensor signal is low, correction processing is added to the pulse wave detection signal or the like. Presenting data with low reliability to the user may be suppressed by taking a technique such as not using it.

  In any case, it is useful to detect an SN state such as a signal. For the detection of the SN state, a method using frequency analysis such as FFT is widely used like the method disclosed in Patent Document 1. Yes. However, in order to perform the frequency analysis, it is necessary to convert the signal value acquired at each timing into the frequency axis, so that the calculation amount is large and the power consumption is also increased. In particular, when using a pulse meter (for example, a pulse meter realized by a wristwatch-type device) that performs all of sensor driving, signal processing, display, and the like inside the device, the battery and processor installed are large. Because of this limitation, an increase in calculation amount and power consumption becomes a big problem.

  Therefore, the present applicant proposes a method for detecting the SN state using the signal value on the time axis without performing frequency analysis. Specifically, the SN state is detected using a change (in a narrow sense, difference information) of the pulse wave sensor signal before the DC component cut.

  In addition, when it is determined that the SN state is bad, the user may be notified of this, but in the present embodiment, the waveform shaping process may be performed on the pulse wave detection signal. Then, pulsation information is calculated based on the pulse wave detection signal after the waveform shaping process.

  By doing in this way, compared with the case where a frequency analysis is performed, detection of SN state is attained with a small calculation amount and power consumption. In addition, when the pulsation information is calculated by performing the waveform shaping process, the reliability of the pulsation information can be expected to be improved as compared with the case where the waveform shaping process is not performed.

  Hereinafter, an example of a system configuration such as a pulsation detection device will be described, and then an SN state detection process using a pulse wave sensor signal before the DC component cut will be described. Then, the waveform shaping process when it is determined that the SN state is bad will be described, and finally the details of the process of the present embodiment will be described using a flowchart.

3. System Configuration Example FIG. 5 shows a system configuration example of an electronic apparatus including the pulsation detection device of this embodiment. The electronic device includes a pulse wave detection unit 10, a body motion detection unit 20, a pulsation detection device 100, and a display unit 70.

  The pulse wave detection unit 10 includes a pulse wave sensor 11, a filter processing unit 15, and A / D conversion units 16-1 and 16-2. However, the pulse wave detection unit 10 is not limited to the configuration in FIG. 5, and various modifications such as omitting some of these components or adding other components are possible.

  The pulse wave sensor 11 uses a photoelectric sensor or the like as described above with reference to FIG. In this embodiment, the filter processing unit 15 is realized by a high-pass filter that performs high-pass filter processing. In the present embodiment, the pulse wave detection unit 10 includes an A / D conversion unit 16-1 and an A / D conversion unit 16-2, and converts each input analog signal into a digital signal and outputs the digital signal.

  As shown in FIG. 5, the pulse wave sensor 11 is connected to the filter processing unit 15 and the A / D conversion unit 16-2. The filter processing unit 15 is connected to the A / D conversion unit 16-1. The A / D conversion unit 16-1 is connected to a waveform shaping unit 1112 described later, and the A / D conversion unit 16-2 is connected to a noise detection unit 1111 described later. That is, the pulse wave sensor signal (pulse wave detection signal, AC component of the pulse wave sensor signal) after the DC component cut is output from the A / D conversion unit 16-1 to the waveform shaping unit 1112. The pulse wave sensor signal before the DC component cut is output from the conversion unit 16-2 to the noise detection unit 1111. In addition, since the output signal to the noise detection unit 1111 only needs to include the DC component of the pulse wave sensor signal, a configuration in which a filter processing unit that performs low-pass filter processing is inserted before the A / D conversion unit 16-2. It may be. In addition, various modifications can be made to the connection of each unit included in the pulse wave detection unit 10.

  The body motion detection unit 20 includes an acceleration sensor 21 and an A / D conversion unit 26. The acceleration sensor 21 is connected to an A / D conversion unit 26, and the A / D conversion unit 26 is connected to a noise detection unit 1111 and a body movement noise reduction unit 115. The body motion detection unit 20 only needs to have a sensor for detecting body motion, and the acceleration sensor 21 may be changed to another sensor, or may have a plurality of sensors.

  The pulsation detection device 100 includes a signal processing unit 110 and a pulsation information calculation unit 120, and the signal processing unit 110 includes a noise detection unit 1111, a waveform shaping unit 1112, and a body motion noise reduction unit 115. However, the pulsation detection device 100 and the signal processing unit 110 are not limited to the configuration of FIG. 5, and some of these components (for example, the body motion noise reduction unit 115) are omitted or other components are added. Various modifications can be made such as.

  As shown in FIG. 5, the noise detection unit 1111 and the waveform shaping unit 1112 are included in the pulse wave signal processing unit 111 in FIG. The noise detection unit 1111 performs SN state detection processing based on the pulse wave sensor signal output from the A / D conversion unit 16-2 and before the DC component cut. A specific method will be described later. In addition, you may use the body movement detection signal from the body movement detection part 20 together for the detection of SN state. The noise detection unit 1111 is connected to the waveform shaping unit 1112 and outputs the detection result of the SN state.

  The waveform shaping unit 1112 performs waveform shaping processing on the pulse wave detection signal acquired from the A / D conversion unit 16-1 based on the detection result of the SN state in the noise detection unit 1111. A specific method will be described later. The waveform shaping unit 1112 is connected to the body motion noise reduction unit 115 and outputs a pulse wave detection signal after the waveform shaping process.

  The body motion noise reduction unit 115 performs body motion noise reduction processing based on the body motion detection signal from the body motion detection unit 20 with respect to the pulse wave detection signal after waveform shaping processing acquired from the waveform shaping unit 1112. . Since the processing contents of the body motion noise reduction unit 115 and the configurations of the pulsation information calculation unit 120 and the display unit 70 are the same as those in FIG. 1, detailed description thereof is omitted.

4). Detection of SN State Next, SN state detection processing using a pulse wave sensor signal (hereinafter also referred to as noise detection signal) before the DC component cut will be described. Note that, as described above, the noise detection signal used by the noise detection unit 1111 may be a signal obtained by removing the AC component (high frequency component) from the pulse wave sensor signal, as long as the DC component is not cut. In the configuration example of FIG. 5, a pulse wave sensor signal (that is, including both a DC component and an AC component) that is not subjected to filter processing is output to the noise detection unit 1111. In the following, in order to simplify the drawing and description Unless otherwise specified, it is assumed that the noise detection signal is a signal obtained by removing the AC component from the pulse wave sensor signal.

  The pulse wave sensor 11 acquires a pulse wave sensor signal at a predetermined timing (for example, a frequency such as 16 Hz). Therefore, for example, a pulse wave sensor signal is acquired every 1/16 second, and the noise detection unit 1111 also acquires a noise detection signal at a corresponding timing. The noise detection unit 1111 includes difference information between a signal value at a processing target timing (the latest noise detection signal acquisition timing in a narrow sense) and a signal value at a past timing (a timing closest to the processing target timing in a narrow sense). Is calculated.

  It is conceivable to use a difference value as the difference information. In this case, the SN state is determined by comparing the difference value with a given threshold value. For example, if the absolute value of the difference value is used as the difference information, when the absolute value is larger than the threshold value, it is determined that the SN state is bad (that is, the amount of mixed noise is large). If the first threshold value (> 0) and the second threshold value (<0) are set without taking an absolute value, and the difference value is positive, the SN state is bad when it is larger than the first threshold value. When the difference value is negative, it may be determined that the SN state is bad when the difference value is smaller than the second threshold value.

  At this time, the threshold value used for the comparison process may be a static value or a dynamic value. A dynamic value is, for example, a value obtained by storing a difference value in a given period in the past and obtained from them. Specifically, it can be clearly distinguished from an average value of past difference values. A good value (such as a value that is three times the average value) may be set.

  Further, the change direction of the noise detection signal may be used as the difference information. If the noise detection signal is a scalar quantity, the difference information is a sign portion of the difference value, which is generally used. However, the noise detection signal may be a vector quantity by using a plurality of signals as the pulse wave sensor signal or combining with other index values. In this case, the change direction of the noise detection signal is the direction of the vector obtained from the difference between the two vectors.

  When the change direction is used, it is determined that the SN state is bad when the change direction is the same in a given period. The same change direction means that if a sign is used, the sign is the same, and if a vector is used, the vector is within a given angle range with respect to the reference vector, etc. Point to. That is, when the change in a certain direction continues, it is determined that the change is due to noise.

  At this time, the period used for determining the change direction may be determined from the cycle of the heartbeat or the like. For example, when a pulse wave sensor signal including an AC component is used as the noise detection signal, the signal value also changes due to the AC component fluctuation (including fluctuation caused by the heartbeat). It must be determined whether it is due to heartbeat or heartbeat. At that time, considering the ecological characteristics of human beings, the case where the pulse rate is less than 30 is rare, so the fluctuation cycle of the AC component is unlikely to be 2 seconds or more. Therefore, if the determination period of the change direction is set to 2 seconds or more, the fluctuation of the AC component should appear in both the first direction and the opposite second direction within the period. It is unlikely to appear in a certain direction. That is, if the change direction is the same in a given period determined from the heartbeat period, the change is considered not to be due to the AC component, and therefore noise detection can be performed appropriately.

  In addition, although the difference value and the change direction were demonstrated as difference information, either of these may be used and both may be used.

  An example of noise detection is shown in FIG. In FIG. 6, the noise detection signal is represented by pulse DC, and the pulse wave detection signal at that time is also represented by pulse AC. As shown in FIG. 6, noise is detected based on the amount of change in the noise detection signal. Note that the noise detection period in FIG. 6 is set in the waveform shaping unit 1112 based on the timing (noise detection timing) when the noise detection unit 1111 detects noise. Although the setting method will be described later, there may be a timing included in the noise detection period and not the noise detection timing.

  Moreover, you may use a body movement detection signal for the detection of SN state. For example, when the acceleration detection value (or the amount of change) from the acceleration sensor 21 is greater than a given threshold, the noise is also detected when noise is detected based on the difference information at the corresponding timing. It is determined as non-detection. When the acceleration detection value is large, it is considered that the noise detection signal fluctuated due to the start of exercise (beginning of walking, starting of running, etc.). This is because it is desirable to use it as data.

  Note that noise is simply not detected for processing, and it is highly possible that body motion noise is mixed in the pulse wave sensor signal. If noise reduction processing is not performed after that, the reliability of pulsation information is low. Become. In other words, the case where the acceleration detection value is large does not positively recognize that there is little noise, but it is processing that leaves as much of a signal as possible, although it may be a lot of noise. However, since the acceleration detection value is large means that the body motion can be detected by the acceleration sensor 21, if the noise reduction processing is performed by the body motion noise reduction unit 115, the noise detection signal There is still a possibility of reducing noise caused by body movement that is a fluctuation factor.

5. Waveform shaping processing When the noise detection unit 1111 determines that the SN state is bad (there is a lot of noise), the waveform shaping unit 1112 may notify the user that the reliability of the pulsation information is low. Waveform shaping processing may be performed on the wave detection signal. Here, three methods will be described as specific examples of the waveform shaping processing. It is assumed that the waveform shaping process is performed on the pulse wave detection signal in a period (noise detection period) corresponding to the noise detection timing. In the noise detection period, the start timing and the end timing are set based on the noise detection timing. If the start timing and end timing coincide with the noise detection timing, the waveform shaping processing target is only the signal at the noise detection timing. It is also possible to set the start timing before the noise detection timing and set the end timing after the noise detection timing.

  In the first method, the value of the pulse wave detection signal in the noise detection period is set to zero. This is also effective in a method of calculating pulsation information by transforming the waveform of the pulse wave detection signal into a rectangular wave and using the rising edge of the rectangular wave. In such a pulsation information calculation method, since it is necessary to obtain a peak or the like from the signal value itself, the accuracy of the calculated pulsation information is low if the waveform of the input pulse wave detection signal is not complete (rather than actual It may output a value far from the heartbeat). Therefore, even if correction processing (a change in amplitude value as described later, etc.) is performed on the pulse wave detection signal, improvement in accuracy of pulsation information cannot be expected, and no output is performed (or more) It is desirable to output 0 as the pulse rate). In this method, since the signal value is uniformly set to 0 in the noise detection period, the processing is easy.

  Note that the first method may be used when performing frequency analysis such as FFT. However, in the method of performing frequency analysis, the period of the pulse wave detection signal used for processing is related to the resolution such as the pulse rate after the calculation. Therefore, in order to ensure the resolution, it is necessary to perform FFT or the like on the pulse wave detection signal for a certain period of time (for example, ten or more seconds). Therefore, even when combining the first method and pulsation information calculation processing by frequency analysis, the signal value of the noise detection period is only 0 after the waveform shaping processing, It is desirable to use a signal in the noise detection period.

  In the second method, processing for reducing the amplitude is performed on the pulse wave signal in the noise detection period. Various methods for reducing the amplitude are conceivable. For example, a simple method in which a coefficient (except 0) having an absolute value smaller than 1 may be applied to each signal value in the noise detection period. A technique of performing midpoint processing or the like using data in a non-detection period may be used.

  In the second method, since the signal value in the noise detection period does not become zero, it is possible to leave a contribution to the pulsation information by the signal in the period.

  In the third method, the pulse wave signal in the noise detection period is replaced with a pulse wave detection signal in a section where noise is not detected. In this case, correspondence between the signal after replacement and the signal before replacement (or an ideal signal in the noise detection period) is not guaranteed at all. However, in the second method, if the method for reducing the amplitude is not carefully set, the waveform of the pulse wave detection signal may become unnatural. If the waveform is unnatural, a large signal in an unexpected frequency band may be obtained. May appear. Therefore, in order to appropriately perform the second method, arbitrary amplitude reduction processing is not allowed, it is necessary to consider processing selection, and processing load may be a problem due to processing. is there. In this respect, the third method is a replacement with an actually acquired pulse wave detection signal even though the acquisition timing is different. Therefore, it is unlikely that a signal in an extreme frequency band will appear. Considering the continuity at the boundary between the noise detection period and the non-detection period, it is unlikely that the waveform will be unnatural in other parts, and this can be realized with easy processing.

  Specific examples of the waveform shaping process are shown in FIGS. 7A and 7B. Similar to FIG. 3A and the like, the upper part represents the time-varying waveform of the pulse wave detection signal, and the lower part represents the frequency spectrum. As shown in the upper left part of FIG. 7A, when noise is mixed in the pulse wave detection signal, the frequency spectrum is as shown in the lower part of FIG. difficult. FIG. 7B shows a signal obtained by performing waveform shaping processing on the pulse wave detection signal of FIG. By applying the waveform shaping process to the signal in the noise detection period, the waveform shown in the upper part of FIG. 7B is obtained, and it is easy to find the peak in the frequency spectrum, and the pulsation information can be accurately calculated. Become.

  The process when noise is detected is not limited to the waveform shaping process, and the pulse wave detection signal in the noise detection period may not be used for the calculation of pulsation information. As described above, in the frequency analysis such as FFT, it is not preferable that the processing target data is reduced. Therefore, it may be applied to a method for obtaining pulsation information by transforming it into a rectangular wave or the like. In this case, it is not necessary to process the pulse wave detection signal in the noise detection period. For example, a noise detection period is set based on the noise detection timing, and information on the noise detection period is output to the pulsation information calculation unit 120. And the pulsation information calculation part 120 should just skip the calculation of pulsation information itself with respect to the acquired pulse wave detection signal of the noise detection period.

6). Details of Processing Details of processing according to this embodiment will be described with reference to a flowchart. Below, the example which uses both a difference value and a change direction (especially the code | symbol of a difference value) is demonstrated as a detection process of SN state. FIG. 9 illustrates an example in which the acceleration detection value is also used. Further, although the waveform shaping process is not specifically described, any of the above-described methods may be used.

FIG. 8 shows a flowchart for explaining the processing of this embodiment. When this process is started, first, a pulse wave sensor signal (noise detection signal) before the DC component cut and a pulse wave sensor signal (pulse wave detection signal) after the DC component cut are acquired (S101, S102). Then, difference information ΔDC between the acquired noise detection signal (for example, DC _k ) and the noise detection signal (for example, DC _k−1 or DC _k−n ) acquired in the past is calculated (S103).

  Here, the absolute value of ΔDC and the change direction (sign) are used to detect the SN state. First, the absolute value of ΔDC is compared with a given threshold value (S104). If the absolute value of ΔDC is larger than the threshold value, noise is mixed in the pulse wave sensor signal (that is, the pulse wave). It is determined that noise is mixed in the detection signal (S105). In addition, in the case of No in S104, whether or not ΔDC and the previous ΔDC are in the same direction to determine whether noise is mixed from another viewpoint (actually, the sign of ΔDC and the previous ΔDC are the same) (S106). In the case of No in S106, it means that there is not much noise mixing in both the absolute value and the sign of ΔDC, so it is determined that noise is not mixed in the pulse wave sensor signal (the SN state is good) ( S107). On the other hand, in the case of Yes in S106, the information on the change direction of ΔDC in the past is also referred to and it is determined whether the state where ΔDC is in the same direction continues for a certain time or more (S108). In the case of No in S108, the process proceeds to S107 and it is determined that the SN state is good. If the answer is Yes in S108, the process proceeds to S105 and it is determined that the SN state is bad.

  Then, after the process of S105, the waveform shaping process is performed on the pulse wave detection signal in a certain period before and after (noise detection period) where noise seems to be mixed (S109). After the processing of S107 or S109, frequency analysis is performed on the pulse wave detection signal (S110). If it is determined in S107 that noise is not mixed, the pulse wave detection signal acquired in S102 is processed, and if it is determined in S105 that noise is mixed, acquired in S102. The signal subjected to the waveform shaping process in S109 with respect to the pulse wave detection signal thus processed is the processing target. Thereafter, based on the result of frequency analysis in S110, a pulse rate calculation process (a calculation process of pulsation information in a broad sense) is performed (S111).

  Further, as described above, a body motion detection signal such as an acceleration detection value may be used to detect the SN state. FIG. 9 shows a flowchart for explaining the processing in this case. Since S201 to S211 in this process are the same as S101 to S111 in FIG. 8, detailed description thereof is omitted. When the body motion detection signal is used, the body motion detection signal is acquired at a timing corresponding to the acquisition of the noise detection signal and the pulse wave detection signal (S201, S202) (S212). In the case of Yes in S204, that is, when the absolute value of the difference value is larger than the threshold value and the SN state is suspected to be bad, the acquired body motion detection signal is compared with the past body motion detection signal, It is determined whether or not has changed suddenly (S213).

  In the case of Yes in S213, it is assumed that there is a situation such as the start of walking or the start of running, and therefore the pulse wave detection signal at this timing is processed in the direction used for the calculation of pulsation information. Specifically, if Yes in S213, the process proceeds to S206 as in the case of No in S204 (no noise was detected). On the other hand, when it is No in S213, the process proceeds to S205, and it is determined that the SN state is bad. In the case of No in S204, the processing after FIG. 8 is the same as that in FIG. 8, and even after Yes in S204, the processing after the determination in S213 is the same as that in FIG.

  In the above embodiment, as shown in FIG. 5, the pulsation detection device 100 includes the signal processing unit 110 that performs processing on the signal from the pulse wave detection unit 10 including the pulse wave sensor 11, and the DC component cut. Based on a pulse wave detection signal that is a subsequent pulse wave sensor signal (the pulse wave sensor signal corresponds to the output of the pulse wave sensor 11), a pulsation information calculation unit 120 that calculates pulsation information is included. Then, the signal processing unit 110 is based on difference information between the signal value at the first timing of the pulse wave sensor signal before the DC component cut and the signal value at the second timing different from the first timing. A noise detection unit 1111 that detects noise of the pulse wave sensor signal is included. The pulsation information calculation unit 120 calculates pulsation information based on the noise detection result in the noise detection unit 1111.

  Thereby, it becomes possible to detect the noise of the pulse wave sensor signal based on the difference information of the pulse wave sensor signal (noise detection signal) before the DC component cut. Since the process using the difference information of the noise detection signal is easier than the frequency analysis process such as FFT, it is possible to reduce the amount of calculation and power consumption. Note that since the pulse wave sensor signal (pulse wave detection signal, AC component of the pulse wave sensor signal) after the DC component cut is used to calculate the pulsation information, the noise detection target should be the pulse wave detection signal. It is. On the other hand, the noise detection signal may not include a component corresponding to the pulse wave detection signal (AC component of the pulse wave sensor signal), and the target of the noise detection processing using the noise detection signal is the pulse wave sensor. Signals (pulse wave sensor signals before DC component cut in a narrow sense) are targeted. However, if noise is mixed in either the noise detection signal or the pulse wave detection signal, there is a high possibility that the same noise will be mixed in the other. Based on the above, the pulse wave detection signal may be evaluated, and it is considered that no problem occurs even if the pulsation information is calculated using the pulse wave detection signal.

  Further, the noise detection unit 1111 may acquire a difference value between the signal value at the first timing and the signal value at the second timing as difference information. Then, when the difference value is larger than a given threshold value, it is determined that noise is detected.

  Thereby, noise detection based on the difference value is possible. Since noise can be detected by comparison processing with a given threshold value, the processing load is reduced compared to frequency analysis or the like. Note that more flexible processing is possible by adaptively setting the threshold value.

  Further, the noise detection unit 1111 acquires the signal value change direction of the pulse wave sensor signal as difference information based on a comparison process between the signal value at the first timing and the signal value at the second timing. Also good. Then, when the signal value change direction is the same direction in a given period, it is determined that noise is detected. The given period here may be a period set based on the length of the pulsation cycle.

  Here, the signal value change direction may be a sign of a difference value in a narrow sense. In this case, that the signal value change direction is the same in a given period indicates a state in which the signs of the difference values are all positive or all negative in the period. The pulsation cycle is a cycle related to pulsation (in particular, movement due to contraction and relaxation of the heart). Since the pulsation is a periodic motion with one cycle of contraction and relaxation, the length (or frequency) of the cycle can be considered. As a given period based on the length of the pulsation cycle, a period longer than a period assumed as a person's pulsation period may be set. For example, it is unlikely that a person's pulse rate falls below 30 (times / minute). Therefore, a period corresponding to 2 seconds, which is the pulsation period when the pulse rate is 30, is set.

  This makes it possible to detect noise based on the signal value change direction. When the signal value change direction is the same in a given period, it means that the signal value of the noise detection signal is monotonously decreasing or monotonically increasing. Here, let us consider a case where the influence of noise sources such as motion, posture, and intensity of external light on the noise detection signal is small (that is, the amount of noise is small). If the noise detection signal does not contain a signal due to the heartbeat (corresponding to the AC component of the pulse wave sensor signal), the main fluctuation factor of the noise detection signal is noise, so the fluctuation should be small, And it is assumed that regularity is not seen in the change direction. That is, if the noise is small, it is unlikely that the signal value monotonously decreases or monotonously increases. Conversely, if the signal value monotonously increases or monotonously decreases, it is suspected that noise is mixed. On the other hand, when the noise detection signal includes the AC component of the pulse wave sensor signal, even if the noise is small, the noise detection signal also fluctuates due to a change caused by the pulsation of the AC component. That is, depending on the setting of a given period used for noise detection, there is a possibility that the signal value monotonously increases (decreases) even if there is little noise, and signal fluctuations derived from heartbeats may be erroneously detected as noise. However, as described above, this can be dealt with by setting a given period based on the length of the pulsation cycle. Because a period longer than a general pulsation cycle is set as a given period, both contraction and relaxation of the heart are performed in the period, and as a result, the timing at which the AC component increases is also included. This is because, since there is a timing to decrease, it is unlikely that the noise detection signal monotonously increases (decreases) only by the contribution of the AC component. Therefore, by setting the above-described period, it is possible to suppress the possibility of erroneously detecting signal fluctuations derived from heartbeats as noise.

  Further, the noise detection unit 1111 acquires a difference value between the signal value at the first timing and the signal value at the second timing as difference information, and the noise is detected when the difference value is larger than a given threshold value. It may be determined that has been detected. At the same time, even when the difference value is equal to or less than a given threshold value, it may be determined that noise is detected when the sign of the difference value is the same code in a given period.

  As a result, as shown in the flowchart of FIG. 8, processing using both the difference value and the change direction thereof is possible. Specifically, if the difference value is large, it is determined that noise has been detected at that time. And when a difference value is small, the determination based on the code | symbol is performed. That is, when noise is not detected in both determinations, it is determined that noise is not detected for the first time. If either one is determined as noise detection, it is determined that noise has been detected. Since noise detection processing from different viewpoints is used together, improvement in noise detection accuracy can be expected. Also in this case, the given period for determining the identity of the code may be set based on the length of the pulsation cycle.

  In addition, the signal processing unit 110 performs a waveform shaping process of the pulse wave detection signal in the noise detection period set based on the noise detection timing that is the timing when the noise detection unit 1111 determines that noise has been detected. A shaping unit 1112 may be included. The pulsation information calculation unit 120 calculates pulsation information based on the pulse wave detection signal after the waveform shaping processing by the waveform shaping unit 1112.

  As a result, when noise is detected, it is possible to calculate pulsation information after performing waveform shaping processing on the pulse wave detection signal, and to improve the reliability of the calculated pulsation information, etc. Is possible. When noise is detected, just notify the user (for example, when data containing noise is used to calculate the beat information to be displayed, display that fact) Even if it exists, it is useful because the user can select the beat information. However, in this case, since the subsequent processing is left to the user, there remains a problem in terms of convenience and the like. Therefore, in this embodiment, it is possible to reduce the load on the user by performing waveform shaping processing before calculating the pulsation information and trying to ensure the accuracy of the pulsation information presented to the user. In addition, after performing the waveform shaping process of this embodiment, the user may be notified that noise is suspected.

  Moreover, the waveform shaping part 1112 may perform the process which reduces the amplitude of a pulse-wave detection signal in a noise detection period as a waveform shaping process. Further, the process of replacing the pulse wave detection signal with another signal in the noise detection period may be performed as the waveform shaping process.

  Here, the process of reducing the amplitude of the pulse wave detection signal may include a process of setting the amplitude value to zero.

  This makes it possible to use the first to third methods described above as the waveform shaping process. In addition, since each method has a different advantage as mentioned above, it is desirable to use properly according to a situation.

  The waveform shaping unit 1112 may perform waveform shaping processing of the pulse wave detection signal in the noise detection period determined by the start timing and end timing set based on the noise detection timing.

  As a result, the waveform shaping process can be performed after the start timing and end timing of the noise detection period are set based on the noise detection timing. For example, both the start timing and the end timing may coincide with the noise detection timing. In this case, the waveform shaping process is targeted for noise detection timing.

An example in which the noise detection timing and the start timing are different is shown in FIG. As shown in FIG. 10, the noise detection signal was almost constant value began monotonously increases from the time t _0. In this case, if the comparison process between the difference value and the threshold is not performed, or if the slope of the noise detection signal is smaller than the threshold, noise detection is performed based on the change direction. However, since the change direction is detected for a given period (for example, a period of 2 seconds or the like set based on the pulsation period), noise is detected for a given period from t _0. a _{t 1} was. However, considering from FIG. 10, there is a high possibility that the mixing of noise started from t _0, and it cannot be said that the waveform shaping process using only the pulse wave detection signal at t ₁ is sufficient. Therefore, by setting the start timing of the noise detection period before the noise detection timing (for example, the timing before the given period used for noise detection), more appropriate waveform shaping processing can be performed. Become.

  On the other hand, when noise is detected at a certain timing, even if noise is not detected as a result of noise detection processing at the timing immediately after that, the noise mixed at the noise detection timing is continuously mixed. The possibility cannot be denied. In that case, a timing after the noise detection timing may be set as the end timing of the noise detection period. Combining the above methods, the start timing is set before the noise detection timing, the end timing is set after the noise detection timing, and the period before and after the noise detection timing is set as the noise detection period. Also good.

  The noise detection unit 1111 determines that noise is detected based on the difference information when the value of the body motion detection signal from the body motion sensor (for example, the acceleration sensor 21) is larger than a given threshold value. In this case, it may be determined that noise is not detected.

  Thus, when the start of a change in body motion such as the start of walking is detected, even if noise (for example, noise due to the body motion) is detected, the pulse wave detection signal at that time is detected as the pulsation information. It is possible to perform processing in the direction used for the calculation. This is because at the start of exercise, it is assumed that the pulsation information also starts to change, so that it can be useful information when analyzing the change of the pulsation information. Note that the final output of the noise detection unit 1111 need not be noise non-detection. For example, as shown in the flowchart of FIG. 9, when used as a process for canceling noise detection in the comparison process between the difference value and the threshold value, if noise is detected again based on the change direction thereafter, the noise detection is performed. The unit 1111 outputs information that noise has been detected.

  The above-described embodiment can also be applied to an electronic device including the pulsation detection device 100 and the pulse wave detection unit 10 described above. The pulse wave detector 10 has a pulse wave sensor 11 and outputs a signal based on the pulse wave sensor signal from the pulse wave sensor. Specifically, the pulse wave detection unit 10 outputs the pulse wave sensor signal before the high-pass filter process to the noise detection unit 1111 and outputs the pulse wave sensor signal after the high-pass filter process as a pulse wave detection signal.

  Thereby, the technique of this embodiment is applicable also to the electronic device containing a pulsation detection apparatus. The electronic device is specifically a pulse meter, and the configuration thereof may be the one shown in FIG. 4A or 4B, or another configuration.

  Further, in the present embodiment, the signal processing unit 110 that processes the signal from the pulse wave detection unit 10 having the pulse wave sensor 11 and the pulse wave sensor signal after the DC component cut (the pulse wave sensor signal is It can also be applied to a program that causes a computer to function as the pulsation information calculation unit 120 that calculates pulsation information based on a pulse wave detection signal that corresponds to the output of the pulse wave sensor 11. Then, the signal processing unit 110 is based on difference information between the signal value at the first timing of the pulse wave sensor signal before the DC component cut and the signal value at the second timing different from the first timing. A noise detection unit 1111 that detects noise of the pulse wave sensor signal is included. The pulsation information calculation unit 120 calculates pulsation information based on the noise detection result in the noise detection unit 1111.

  As a result, the processing of this embodiment can be realized by a program. For example, it may be a program that is read and executed by a processing unit (for example, DSP) of a device as shown in FIG. Further, the pulse wave detection device worn by the user may include a pulse wave sensor 11 and a communication unit that communicates a pulse wave sensor signal from the pulse wave sensor 11 wirelessly or by wire. In that case, the program of this embodiment is provided separately from the pulse wave detection device, and is read and executed by a processing unit (for example, a CPU) of an information processing system that receives a pulse wave sensor signal from the communication unit. The This information processing system may not be assumed to be worn by a user such as a PC, or may be assumed to be worn (mobile) by a user such as a smartphone. Further, a server system or the like connected via a network such as the Internet may be used as the information processing system. When the pulse wave detection device and the information processing system on which the program is executed are separate, a display unit used for presenting pulsation information to the user is provided at an arbitrary location. For example, the information may be displayed on a display unit of the information processing system, or a pulse wave detection device may be provided with a display unit to display pulsation information output from the information processing system. Moreover, you may display on the display part of different apparatuses (for example, arbitrary client apparatuses, etc. when a server system is used as an information processing system).

  The program is recorded on an information storage medium. Here, as the information recording medium, various recording media that can be read by an information processing system such as an optical disk such as a DVD or a CD, a magneto-optical disk, a hard disk (HDD), a memory such as a nonvolatile memory or a RAM can be assumed. .

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the configuration and operation of the pulsation detecting device and the like are not limited to those described in the present embodiment, and various modifications can be made.

10 pulse wave detection unit, 11 pulse wave sensor, 15 filter processing unit,
16 A / D converter, 20 body motion detector, 21 acceleration sensor,
22 pressure sensor, 26 A / D converter, 70 display, 100 pulsation detection device,
111 pulse wave signal processing unit, 113 body motion signal processing unit, 115 body motion noise reduction unit,
120 beat information calculation unit, 300 holding mechanism, 302 guide, 400 base unit,
1111 Noise detection unit, 1112 Waveform shaping unit

Claims (12)

A signal processing unit that performs processing on a signal from a pulse wave detection unit having a pulse wave sensor that outputs a pulse wave sensor signal;
A pulsation information calculation unit that calculates pulsation information based on the pulse wave detection signal that is the pulse wave sensor signal after the DC component cut;
Including
The signal processing unit
A signal value at a first timing of the pulse wave sensor signal before the DC component cut and a signal value of the pulse wave sensor signal before the DC component cut at a second timing different from the first timing Based on the difference information, including a noise detection unit that detects noise of the pulse wave sensor signal,
The pulsation information calculator is
The pulsation detecting device, wherein the pulsation information is calculated based on a detection result of the noise in the noise detection unit. In claim 1,
The noise detector is
The difference value between the signal value at the first timing and the signal value at the second timing is acquired as the difference information, and based on the result of the comparison process between the difference value and a given threshold, A pulsation detecting device characterized by detecting noise. In claim 1 or 2,
The noise detector is
The signal value change direction of the pulse wave sensor signal before the DC component cut is acquired as the difference information by a comparison process of the signal value at the first timing and the signal value at the second timing, The pulsation detecting device, wherein the noise is determined to be detected when the signal value change direction is the same direction in a given period. In claim 1,
The noise detector is
Obtaining a difference value between the signal value at the first timing and the signal value at the second timing as the difference information;
If the difference value is greater than a given threshold, determine that the noise has been detected;
Even if the difference value is less than or equal to a given threshold value, it is determined that the noise is detected if the sign of the difference value is the same code in a given period. Detection device. In claim 3 or 4,
The noise detector is
A pulsation detecting apparatus, characterized in that it is determined whether or not the noise is detected in the given period set in accordance with a length of a pulsation cycle. In any one of Claims 1 thru | or 5,
The signal processing unit
A waveform shaping unit that performs waveform shaping processing of the pulse wave detection signal in a noise detection period set based on a noise detection timing that is a timing at which the noise is detected by the noise detection unit;
The pulsation information calculator is
The pulsation detecting device, wherein the pulsation information is calculated based on the pulse wave detection signal after the waveform shaping processing by the waveform shaping unit. In claim 6,
The waveform shaping unit
The pulsation detecting device, wherein the processing for reducing the amplitude of the pulse wave detection signal in the noise detection period is performed as the waveform shaping processing. In claim 6,
The waveform shaping unit
The pulsation detecting device characterized in that processing for replacing the pulse wave detection signal in the noise detection period with another signal is performed as the waveform shaping processing. In any of claims 6 to 8,
The waveform shaping unit
The pulsation detecting device, wherein the waveform shaping process of the pulse wave detection signal is performed in the noise detection period determined by a start timing and an end timing set based on the noise detection timing. In any one of Claims 1 thru | or 9,
The noise detector is
When the value of the body motion detection signal from the body motion sensor is larger than a given threshold, the noise is not detected even when it is determined that the noise is detected based on the difference information. A pulsation detecting device characterized by determining. The pulsation detecting device according to any one of claims 1 to 10,
The pulse wave sensor, and the pulse wave detector that outputs a signal based on the pulse wave sensor signal from the pulse wave sensor;
Including
The pulse wave detector
The pulse wave sensor signal before the high-pass filter process is output to the noise detection unit as the pulse wave sensor signal before the DC component cut, and the pulse wave sensor signal after the high-pass filter process is output after the DC component cut. An electronic apparatus that outputs the pulse wave detection signal that is the pulse wave sensor signal. A signal processing unit that performs processing on a signal from a pulse wave detection unit having a pulse wave sensor that outputs a pulse wave sensor signal;
As a pulsation information calculation unit that calculates pulsation information based on the pulse wave detection signal that is the pulse wave sensor signal after the DC component cut,
Make the computer work,
The signal processing unit
A signal value at a first timing of the pulse wave sensor signal before the DC component cut and a signal value of the pulse wave sensor signal before the DC component cut at a second timing different from the first timing Based on the difference information, including a noise detection unit that detects noise of the pulse wave sensor signal,
The pulsation information calculator is
The program which calculates the pulsation information based on the detection result of the noise in the noise detection part.

Images