JP7160460B2 - Pulse rate calculation method, pulse rate calculation device, recording medium - Google Patents

Description

The present invention relates to a pulse rate calculation method, a pulse rate calculation device, and a recording medium.

The pulse rate may be calculated by measuring the pulse using a wearable device worn on the body. It is known that disturbance noise due to body movement or the like poses a problem when performing measurements using such wearable devices.

For example, Patent Literature 1 is known as a technique for dealing with noise as described above. Patent Literature 1 describes a pulse detection device having a pulse wave sensor, a body motion sensor, a pulse wave signal filtering section, and a filter coefficient setting section. According to Patent Document 1, a filter coefficient setting unit sets a coefficient of an adaptive filter to a predetermined value when it detects that a change in body motion has increased beyond a predetermined threshold based on a body motion signal. The pulse wave signal filtering unit generates an adaptive filter based on the body motion signal to extract a noise signal in the pulse wave signal, and outputs a pulse signal obtained by removing noise from the pulse wave signal.

JP 2010-172645 A

In the case of the technique described in Patent Document 1, in order to remove noise, it is necessary to have a body motion sensor in addition to the pulse wave sensor. Therefore, the noise cannot be removed without the body motion sensor, and it is difficult to reduce the influence of the noise with a simple configuration.

Also, as a method of estimating the pulse rate from a pulse wave signal containing disturbance noise such as body motion, there is a method of removing noise in the frequency domain by fast Fourier transform or the like. However, there is a trade-off between time resolution and frequency resolution in the Fourier transform. Therefore, when Fourier transform is performed, it is difficult to obtain frequency resolution for accurately estimating the pulse rate while maintaining the time resolution necessary for heart rate variability analysis. There is a report that, for example, heart rate variability analysis used for evaluation of autonomic nerve function requires a pulse wave signal sampling rate of about 25 Hz.

As described above, when calculating the pulse rate using a wearable device, there is a problem that it is difficult to reduce the influence of noise with a simple configuration without relying on the Fourier transform. Therefore, the present invention provides a pulse rate calculation method that solves the problem that it is difficult to reduce the influence of noise with a simple configuration without relying on the Fourier transform when calculating the pulse rate using a wearable device. An object of the present invention is to provide a number calculation device and a recording medium.

In order to achieve such an object, a pulse rate calculation method, which is one aspect of the present invention, comprises:
A pulse rate calculation method performed by a pulse rate calculation device that calculates a pulse rate based on a measured pulse wave signal,
A plurality of types of low-pass filters with different attenuation frequencies are applied to the pulse wave signal, and the pulse rate is calculated based on the application result.

In addition, a pulse rate calculation device, which is another embodiment of the present invention,
A pulse rate calculator for calculating a pulse rate based on a measured pulse wave signal,
and a pulse rate calculator that applies a plurality of types of low-pass filters with different frequencies to attenuate to the pulse wave signal and calculates the pulse rate based on the result of the application.

A recording medium according to another aspect of the present invention is
A pulse rate calculator that calculates the pulse rate based on the measured pulse wave signal,
A computer readable program recording a program for realizing a pulse rate calculation unit that applies a plurality of types of low-pass filters with different frequencies to attenuate to the pulse wave signal and calculates the pulse rate based on the application results. A recording medium.

By being configured as described above, the present invention solves the problem that it is difficult to reduce the influence of noise with a simple configuration without relying on the Fourier transform when calculating the pulse rate using a wearable device. It is possible to provide a pulse rate calculation method, a pulse rate calculation device, and a recording medium that solve the problem.

1 is a block diagram showing an example of a configuration of a wearable device according to a first embodiment of the invention; FIG. It is a figure for demonstrating an example of a process of a pulse wave sensor. 2 is a block diagram showing an example of a configuration of a processing unit shown in FIG. 1; FIG. FIG. 5 is a diagram for explaining an example of processing for removing baseline fluctuations; FIG. 5 is a diagram for explaining an example of processing for removing baseline fluctuations; It is a figure for demonstrating an example of the process which detects a peak value. FIG. 4 is a diagram for explaining an example of peak intervals used when detecting peak values; FIG. FIG. 4 is a diagram for explaining an example of feedback processing; FIG. 4 is a flow chart showing an example of the operation of a processing unit according to the first embodiment of the present invention; 7 is a flow chart showing an example of an operation when performing processing for detecting a peak value; 4 is a flow chart showing an example of an operation when performing processing for calculating a pulse rate; 7 is a flow chart showing an example of an operation when feedback processing is performed; FIG. 4 is a block diagram showing an example of the configuration of a pulse rate calculation device according to a second embodiment of the present invention; FIG.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 to 12. FIG. FIG. 1 is a block diagram showing an example of the configuration of the wearable device 100. As shown in FIG. FIG. 2 is a diagram for explaining an example of processing of pulse wave sensor 210. As shown in FIG. FIG. 3 is a block diagram showing an example of the configuration of the processing section 220. As shown in FIG. 4 and 5 are diagrams for explaining an example of processing for removing baseline fluctuations. FIG. 6 is a diagram for explaining an example of processing for detecting peak values. FIG. 7 is a diagram for explaining an example of peak intervals used when detecting peak values. FIG. 8 is a diagram for explaining an example of feedback processing. FIG. 9 is a flow chart showing an example of the operation of the processing unit 220. As shown in FIG. FIG. 10 is a flow chart showing an example of the operation when performing processing for detecting a peak value. FIG. 11 is a flowchart showing an example of the operation when performing processing for calculating the pulse rate. FIG. 12 is a flow chart showing an example of the operation when feedback processing is performed.

In the first embodiment of the present invention, the wearable device 100 that calculates the pulse rate, which is the number of pulses per minute, using the pulse wave signal acquired by the pulse wave sensor 210 will be described. As will be described later, in the wearable device 100 of the present embodiment, after applying a high-pass filter (HPF: High-pass filter) to the acquired pulse wave signal to remove baseline fluctuations, two types of low-pass with different frequencies to be attenuated Apply a filter (LPS: Low-pass filter). Then, wearable device 100 detects a pulse peak based on the result of applying two types of low-pass filters. After that, the wearable device 100 calculates the pulse rate from the peak interval obtained based on the peak detection result.

The wearable device 100 is an information processing device such as a wristwatch that is worn on the body and measures a pulse wave signal. FIG. 1 shows an example of the configuration of the wearable device 100. As shown in FIG. Referring to FIG. 1 , wearable device 100 incorporates sensor board 200 including pulse wave sensor 210 and processing unit 220 .

Pulse wave sensor 210 is, for example, a photoelectric sensor. FIG. 2 shows an example of measurement by the pulse wave sensor 210. As shown in FIG. As shown in FIG. 2, for example, the pulse wave sensor 210 irradiates the body with green LED light. Pulse wave sensor 210 measures the pulse wave signal by measuring the light reflected from the body on which wearable device 100 is worn. For example, as described above, the pulse wave sensor 210 is configured to be able to measure a pulse wave signal using a photoelectric capacitive pulse wave method (PPG: Photoplethysmography).

It is reported that heart rate variability analysis used for autonomic nerve function evaluation requires a pulse wave signal sampling rate of about 25 Hz, which indicates the number of measurements per second. Therefore, it is desirable that the sampling rate of the pulse wave signal in this embodiment is 25 Hz or more.

The processing unit 220 is an information processing unit (pulse rate calculation device) such as a microcomputer that calculates the pulse rate based on the pulse wave signal measured by the pulse wave sensor 210 . FIG. 3 shows an example of the configuration of the processing unit 220. As shown in FIG. Referring to FIG. 3, the processing section 220 has, for example, a baseline fluctuation removal section 221, a peak detection section 222, a pulse rate calculation section 223, and a feedback section 224. FIG.

For example, each of the processing units described above can be realized by various logic circuits and hardware, such as a peak detection circuit that performs peak detection and a pulse rate estimation circuit that calculates and feeds back the pulse rate. Each of the processing units described above may be implemented by executing a program stored in a storage device by an arithmetic device such as a CPU (Central Processing Unit).

The baseline fluctuation remover 221 applies a high-pass filter to the pulse wave signal measured by the pulse wave sensor 210 . Thereby, the baseline fluctuation removing unit 221 removes the baseline fluctuation from the pulse wave signal measured by the pulse wave sensor 210 .

For example, as shown in FIG. 4, in the pulse wave signal measured by the pulse wave sensor 210, the baseline may fluctuate due to the wearer wearing the wearable device 100 moving. Therefore, the baseline fluctuation removing unit 221 applies a predetermined high-pass filter such as 0.5 Hz, for example. As a result, as shown in FIG. 5, a flat state in which the baseline of the pulse wave signal is aligned to 0 can be obtained.

It should be noted that the value of the frequency attenuated by the baseline fluctuation removing section 221 may be configured to be appropriately changeable according to the type of signal. That is, the high-pass filter used by the baseline fluctuation removing section 221 is not limited to the 0.5 Hz high-pass filter.

The peak detection unit 222 applies two types of low-pass filters with different attenuation frequencies, and then detects a pulse peak based on the application results.

For example, the peak detector 222 makes two copies of the pulse wave signal from which the baseline fluctuation has been removed by the baseline fluctuation remover 221 . Then, the peak detection unit 222 applies a 3 Hz low-pass filter to one of the two copies, and applies a 10 Hz low-pass filter to the other of the two copies.

A peak detector 222 detects a peak present within an estimated range described later from the pulse wave signal to which the 3 Hz low-pass filter is applied. Also, if the pulse wave signal to which the 3 Hz low-pass filter is applied does not have a peak within the estimation range, the peak detection unit 222 detects the peak present within the same estimation range from the pulse wave signal to which the 10 Hz low-pass filter is applied. to detect In this way, the peak detector 222 detects peaks using the pulse wave signal to which the 3 Hz low-pass filter is applied and the pulse wave signal to which the 10 Hz low-pass filter is applied. Note that the peak detection by the peak detection unit 222 may be performed using a known method such as detecting a change in the slope of the tangent line of the pulse wave signal.

Now, with reference to FIG. 6, the estimation range will be described in detail. FIG. 6 is a diagram for explaining the estimated range. Referring to FIG. 6, the peak detection unit 222 sets an estimation range, which is a range for estimating the next peak, based on the pulse rate (for estimation), which is a reference value. For example, the peak detector 222 calculates the peak interval from the previous peak to the next peak when a predetermined value is added to the pulse rate (for estimation). The peak detector 222 also calculates the peak interval when a predetermined value is subtracted from the pulse rate (for estimation). Then, the peak detection unit 222 defines an estimation range between the peak interval when a predetermined value is added to the pulse rate (for estimation) and the peak interval when a predetermined value is subtracted from the pulse rate (for estimation). set.

Also, the peak detector 222 can calculate the reference value from the pulse rate (for estimation). A reference value is a value indicating a peak interval in the case of a pulse rate (for estimation).

For example, if the peak interval is represented by the number of sampled data, the peak interval is (sampling rate [Hz]) / (pulse rate (for estimation) added or subtracted as necessary) x 60 It can be obtained in [seconds]. For example, it is assumed that the value to be added is 30 bpm and the value to be subtracted is 25 bpm, and the initial value of 80 bpm is used as the pulse rate (for estimation). Also assume that the sampling rate is 110 Hz. In this case, the peak detector 222 calculates 110/(80+30)×60=60 and 110/(80−25)×60=120. Then, the peak detection unit 222 sets the estimated range to be between 60 and 120 pieces of sample data from the previous peak. Also, the peak detector 222 can calculate 110/80×60=82.5 as the reference value.

A plurality of peaks may be detected within the estimation range due to the influence of noise or the like. In this case, the peak detector 222 can be configured to adopt a peak closer to the above-described reference value among the plurality of detected peaks.

Also, there are cases where the pulse wave signal to which the 10 Hz low-pass filter is applied does not have a peak within the estimation range. In this case, the peak detector 222 determines that the peak cannot be detected. Then, the peak detection unit 222 can handle, for example, that a peak exists at the position of the reference value.

If the above is put together, it will come to show in FIG. 7, for example. FIG. 7 shows an example of peak detection processing by the peak detector 222. As shown in FIG. Referring to FIG. 7, the peak detector 222 detects a peak existing within an estimated range from the previous peak using the pulse wave signal to which a 3 Hz low-pass filter is applied. If the pulse wave signal to which the 3 Hz low-pass filter is applied has a peak within the estimation range, the peak detector 222 does not check the pulse wave signal to which the 10 Hz low-pass filter is applied. Also, if the pulse wave signal to which the 3 Hz low-pass filter is applied cannot detect a peak within the estimation range, the peak detection unit 222 uses the pulse wave signal to which the 10 Hz low-pass filter is applied to detect the peak within the same estimation range. to detect Also, if the pulse wave signal to which the 10 Hz low-pass filter is applied does not have a peak within the estimation range, the peak detector 222 treats it as having a peak at the position of the reference value. For example, by repeating the above processing, the peak detection unit 222 detects a peak based on the pulse wave signal to which a 3 Hz low-pass filter is applied and the pulse wave signal to which a 10 Hz low-pass filter is applied, as shown in FIG. detection.

Note that the initial value of the pulse rate (for estimation), the value to be added, and the value to be subtracted may be values other than those exemplified. In addition, the pulse rate (for estimation) is appropriately changed by feedback processing, which will be described later. In other words, the pulse rate (for estimation), which is a reference value, is appropriately changed based on the calculation result of the pulse rate.

Further, the value of the frequency attenuated by the peak detection section 222 may be configured to be appropriately changeable according to the type of signal or the like. That is, the low-pass filter used by the peak detector 222 is not limited to the low-pass filters of 3 Hz and 10 Hz.

Pulse rate calculator 223 calculates the pulse rate based on the peak detected by peak detector 222 . For example, the pulse rate calculator 223 calculates the pulse rate from the peak interval between the previous peak and the peak detected by the peak detector 222 .

For example, the pulse rate calculator 223 calculates the peak interval by counting the number of pieces of sampling data between the previous peak and the peak detected by the peak detector 222 . Then, the pulse rate calculator 223 calculates the pulse rate based on the calculated peak interval. Specifically, for example, the pulse rate calculator 223 calculates the pulse rate by calculating (sampling rate [Hz])/(peak interval)×60 [seconds]. For example, if the sampling rate is 110 Hz and the peak interval is 110, the pulse rate calculator 223 calculates 110/110×60=60 as the pulse rate.

If neither the pulse wave signal to which the 3 Hz low-pass filter is applied nor the pulse wave signal to which the 10 Hz low-pass filter is applied does not have a peak within the estimation range, the pulse rate calculation unit 223 calculates a new pulse rate. is not performed, and the previously calculated pulse rate may be used.

The feedback section 224 performs feedback processing based on the pulse rate calculated by the pulse rate calculation section 223 . For example, the feedback unit 224 changes the pulse rate (for estimation) used when setting the estimation range based on the pulse rate calculated by the pulse rate calculation unit 223 .

For example, the feedback unit 224 determines whether the pulse rate calculated by the pulse rate calculation unit 223 is greater than the value obtained by adding a predetermined value to the pulse rate calculated last time, or the pulse rate calculated by the pulse rate calculation unit 223 is greater than the pulse rate calculated last time. Check if it is less than the value obtained by subtracting a predetermined value from the pulse rate. If the pulse rate calculated by the pulse rate calculator 223 is greater than the value obtained by adding a predetermined value to the previously calculated pulse rate, the feedback section 224 adds a predetermined value to the pulse rate (for estimation). New pulse rate (for estimation). If the pulse rate calculated by the pulse rate calculator 223 is smaller than the value obtained by subtracting a predetermined value from the previously calculated pulse rate, the feedback section 224 subtracts a predetermined value from the pulse rate (for estimation). New pulse rate (for estimation).

FIG. 8 shows an example of feedback processing by the feedback section 224 described above. Referring to FIG. 8, for example, when the pulse rate calculated by the pulse rate calculation unit 223 is greater than the value obtained by adding a predetermined value of 5 bpm to the previously calculated pulse rate, the feedback unit 224 changes the pulse rate (for estimation) to A new pulse rate (for estimation) is obtained by adding a predetermined value of 3 bpm. Further, when the pulse rate calculated by the pulse rate calculation unit 223 is smaller than the value obtained by subtracting the predetermined value of 5 bpm from the pulse rate calculated last time, the feedback unit 224 calculates the pulse rate (for estimation) with a predetermined value. A certain 3 bpm is subtracted to obtain a new pulse rate (for estimation). If the pulse rate calculated by the pulse rate calculation unit 223 is greater than or equal to the value obtained by subtracting a predetermined value of 5 bpm from the previously calculated pulse rate and less than or equal to the value obtained by adding the predetermined value of 5 bpm to the previously calculated pulse rate, feedback is performed. The unit 224 can use the previous pulse rate (for estimation) as a new pulse rate (for estimation).

For example, as described above, the feedback unit 224 performs feedback processing on the pulse rate (for estimation) used when setting the estimation range, based on the pulse rate calculated by the pulse rate calculation unit 223 . Note that the feedback unit 224 may be configured to perform feedback processing by a method other than the above example, such as using the pulse rate calculated by the pulse rate calculation unit 223 as the pulse rate (for estimation).

Note that the various predetermined values and predetermined values described above are examples. Values used when the feedback unit 224 performs feedback processing may be values other than those illustrated.

The above is an example of the configuration of the processing unit 220 . Next, an example of the operation of the processing unit 220 will be described with reference to FIGS. 9 to 12. FIG. First, referring to FIG. 9, the flow of the overall operation when the processing unit 220 calculates the pulse rate will be described.

Referring to FIG. 9 , baseline fluctuation remover 221 applies a high-pass filter to the pulse wave signal measured by pulse wave sensor 210 . Thereby, the baseline fluctuation removing unit 221 removes the baseline fluctuation from the pulse wave signal measured by the pulse wave sensor 210 (step S101).

The peak detector 222 applies two types of low-pass filters with different attenuation frequencies (step S202). For example, the peak detector 222 makes two copies of the pulse wave signal from which the baseline fluctuation has been removed by the baseline fluctuation remover 221 . Then, the peak detection unit 222 applies a 3 Hz low-pass filter to one of the two copies, and applies a 10 Hz low-pass filter to the other of the two copies.

The peak detector 222 detects peaks using the pulse wave signal to which the 3 Hz low-pass filter is applied and the pulse wave signal to which the 10 Hz low-pass filter is applied (step S103). For example, the peak detection unit 222 first tries to detect a peak existing within the estimated range from the previous peak using the pulse wave signal to which a 3 Hz low-pass filter is applied. Also, in the pulse wave signal to which the 3 Hz low-pass filter is applied, if the next peak does not exist within the estimation range from the previous peak, the peak detection unit 222 uses the pulse wave signal to which the 10 Hz low-pass filter is applied, Attempt to find peaks that are within the estimated range from the previous peak.

The pulse rate calculator 223 calculates the pulse rate from the peak interval between the previous peak and the peak detected by the peak detector 222 (step S104). For example, the pulse rate calculator 223 calculates the pulse rate by calculating (sampling rate [Hz])/(peak interval)×60 [seconds].

The feedback unit 224 performs feedback processing based on the pulse rate calculated by the pulse rate calculation unit 223 (step S105). For example, the feedback unit 224 changes the pulse rate (for estimation) used when setting the estimation range based on the pulse rate calculated by the pulse rate calculation unit 223 .

The processing unit 220 repeats each process of detecting a peak using the estimation range, calculating the pulse rate according to the peak interval, and feedback processing for changing the pulse rate (for estimation), thereby calculating the pulse rate in real time. process. Next, with reference to FIG. 10, the process of step S103 will be described in more detail.

Referring to FIG. 10, the peak detector 222 detects a peak existing within the estimation range from the pulse wave signal to which the 3 Hz low-pass filter is applied (step S201).

If the pulse wave signal to which the 3 Hz low-pass filter is applied has a peak within the estimation range (step S202, Yes), the peak detection unit 222 terminates peak detection. On the other hand, if there is no peak within the estimated range (step S202, No), the peak detection unit 222 detects a peak within the same estimated range from the pulse wave signal to which the 10 Hz low-pass filter is applied (step S203).

If the pulse wave signal to which the 10 Hz low-pass filter is applied has a peak within the estimation range (step S204, Yes), the peak detection unit 222 terminates peak detection. On the other hand, if there is no peak within the estimated range (step S204, No), the peak detector 222 determines that the peak cannot be detected (step S205). In this case, the peak detection unit 222 can be configured to handle, for example, a peak at the position of the reference value.

Next, with reference to FIG. 11, the process of step S104 will be described in more detail.

Referring to FIG. 11, when the peak detection unit 222 has successfully detected a peak (step S301, Yes), the pulse rate calculation unit 223 detects the peak between the previous peak and the peak detected by the peak detection unit 222. Intervals are calculated (step S302). For example, the pulse rate calculator 223 calculates the peak interval by counting the number of sampling data between peaks.

The pulse rate calculator 223 calculates the pulse rate using the calculated peak interval. For example, the pulse rate calculator 223 calculates the pulse rate by calculating (sampling rate [Hz])/(peak interval)×60 [seconds] (step S303).

On the other hand, if the peak detection unit 222 could not detect a peak (step S301, No), the pulse rate calculation unit 223 adopts the pulse rate calculated last time (step S304).

Next, with reference to FIG. 12, the process of step S105 will be described in more detail.

Referring to FIG. 12, when the pulse rate calculated by the pulse rate calculator 223 is greater than the value obtained by adding a predetermined value of 5 bpm to the previously calculated pulse rate (step S401, Yes), the feedback section 224 outputs the pulse rate ( 3 bpm, which is a predetermined value, is added to (for estimation) (step S402). Then, the feedback unit 204 sets a value obtained by adding a predetermined value of 3 bpm to the pulse rate (for estimation) as a new pulse rate (for estimation) (step S406).

If the pulse rate calculated by the pulse rate calculation unit 223 is equal to or less than the value obtained by adding the predetermined value of 5 bpm to the previously calculated pulse rate (step S401, No), the feedback unit 224 outputs the pulse rate calculated by the pulse rate calculation unit 223. It is checked whether or not the pulse rate is smaller than a value obtained by subtracting a predetermined value of 5 bpm from the previously calculated pulse rate.

If the pulse rate calculated by the pulse rate calculation unit 223 is smaller than the value obtained by subtracting the predetermined value of 5 bpm from the pulse rate calculated last time (step S403, Yes), the feedback unit 224 determines a predetermined value from the pulse rate (for estimation). 3 bpm, which is the obtained value, is subtracted (step S404). The feedback unit 204 then sets a value obtained by subtracting a predetermined value of 3 bpm from the pulse rate (for estimation) as a new pulse rate (for estimation) (step S406). On the other hand, when the pulse rate calculated by the pulse rate calculation unit 223 is equal to or greater than the value obtained by subtracting the predetermined value of 5 bpm from the pulse rate calculated last time (step S403, No), the feedback unit 224 returns the previous pulse rate (estimated (for estimation) is set as it is (step S405) as a new pulse rate (for estimation) (step S406).

Thus, the processing section 220 has a peak detection section 222 and a pulse rate calculation section 223 . With such a configuration, the peak detector 222 can detect a pulse peak based on the results of applying two types of low-pass filters. The pulse rate calculator 223 can also calculate the pulse rate based on the peaks detected by the peak detector 222 using two types of low-pass filters. As a result, the peak can be detected more reliably, and the pulse rate can be calculated more accurately. That is, according to the above configuration, it is possible to reduce the influence of noise and accurately calculate the pulse rate with a simple configuration without using a body motion sensor or the like and without using Fourier transform. .

Also, the peak detector 222 is configured to detect a peak based on the estimated range. With such a configuration, peaks can be detected with higher accuracy. Also, the estimation range is configured to be set based on the pulse rate (for estimation) updated by feedback processing by the feedback section 224 . With such a configuration, peaks can be detected with higher accuracy.

In addition, in this embodiment, the peak detection part 222 illustrated the case where two types of low-pass filters are applied. However, the number of low-pass filters applied by peak detector 222 is not limited to two. For example, the peak detection unit 222 may be configured to detect peaks by applying a plurality of low-pass filters of three or more types.

Moreover, in the present embodiment, the case where the feedback processing is performed by the feedback section 224 each time the pulse rate calculation section 223 calculates the pulse rate has been exemplified. However, the feedback processing by the feedback unit 224 does not necessarily have to be performed every time.

[Second embodiment]
A second embodiment of the present invention will now be described with reference to FIG. In the second embodiment, an overview of the configuration of the pulse rate calculator 30 will be described.

The pulse rate calculator 30 is an information processing device (or circuit device) that calculates the pulse rate based on the measured pulse wave signal. Referring to FIG. 13, the pulse rate calculator 30 has a pulse rate calculator 31, for example.

The processing unit described above can be realized by hardware such as a logic circuit, for example. The processing unit described above may be implemented by, for example, executing a program stored in a storage device by an arithmetic device such as a CPU.

After acquiring the pulse wave signal, the pulse rate calculator 31 applies a plurality of types of low-pass filters with different frequencies to attenuate to the acquired pulse wave signal. Then, the pulse rate calculator 31 calculates the pulse rate based on the result of the application.

Thus, the pulse rate calculator 30 has the pulse rate calculator 31 . With such a configuration, the pulse rate calculator 31 can calculate the pulse rate based on the result of applying a plurality of types of low-pass filters with different attenuation frequencies to the pulse wave signal. As a result, the peak can be detected more reliably, and the pulse rate can be calculated more accurately. This makes it possible to reduce the influence of noise and accurately calculate the pulse rate with a simple configuration without using Fourier transform.

Further, the pulse rate calculation device 30 described above can be realized by incorporating a predetermined program into the pulse rate calculation device 30 . Specifically, the program, which is another embodiment of the present invention, applies a plurality of types of low-pass filters having different frequencies to attenuate to the pulse wave signal in the pulse rate calculation device 30 that calculates the pulse rate based on the acquired pulse wave signal. It is a program for realizing a pulse rate calculation unit 31 that applies and calculates the pulse rate based on the result of application.

Further, the pulse rate calculation method executed by the pulse rate calculation device 30 described above is a pulse rate calculation method performed by the pulse rate calculation device that calculates the pulse rate based on the acquired pulse wave signal. In this method, different types of low-pass filters are applied to the pulse wave signal, and the pulse rate is calculated based on the results of the application.

Even the invention of the program or the pulse rate calculation method having the configuration described above can achieve the above-described object of the present invention because it has the same action and effect as the pulse rate calculation device 30 described above. I can.

<Appendix>
Some or all of the above embodiments may also be described as the following appendices. An outline of the pulse rate calculation method and the like according to the present invention will be described below. However, the present invention is not limited to the following configurations.

(Appendix 1)
A pulse rate calculation method performed by a pulse rate calculation device that calculates a pulse rate based on an acquired pulse wave signal,
A pulse rate calculation method, comprising: applying a plurality of types of low-pass filters with different frequencies to attenuate to the pulse wave signal, and calculating the pulse rate based on the results of the application.
(Appendix 2)
The pulse rate calculation method according to Supplementary Note 1,
A pulse rate calculation method for calculating a pulse rate based on a pulse peak detected based on a result of applying a plurality of types of low-pass filters.
(Appendix 3)
The pulse rate calculation method according to appendix 2,
A pulse rate calculation method, comprising: setting an estimation range based on a reference value; and detecting a pulse peak within the estimation range from a previous peak.
(Appendix 4)
The pulse rate calculation method according to appendix 3,
Calculating a peak interval when a predetermined value is added to the reference value and a peak interval when a predetermined value is subtracted from the reference value, and determining the estimated range based on the calculated result Sets the pulse rate calculation method.
(Appendix 5)
The pulse rate calculation method according to Supplementary Note 3 or Supplementary Note 4,
The pulse rate calculation method, wherein the reference value is a value that is changed based on a pulse rate calculation result.
(Appendix 6)
The pulse rate calculation method according to any one of appendices 3 to 5,
A pulse rate calculation method for determining whether a peak pulse exists within the estimated range in a result obtained by applying another low-pass filter when a pulse peak does not exist in the estimated range in a result obtained by applying a certain low-pass filter.
(Appendix 7)
The pulse rate calculation method according to any one of appendices 2 to 6,
A pulse rate calculation method for calculating a pulse rate based on a peak interval between a detected pulse peak and a previous pulse peak.
(Appendix 8)
The pulse rate calculation method according to any one of appendices 1 to 7,
A pulse rate calculation method comprising: applying a predetermined high-pass filter to the pulse wave signal, and then applying a plurality of types of low-pass filters having different frequencies to attenuate.
(Appendix 9)
A pulse rate calculation device that calculates a pulse rate based on the acquired pulse wave signal,
A pulse rate calculation device, comprising: a pulse rate calculator that applies a plurality of types of low-pass filters with different frequencies to attenuate to the pulse wave signal and calculates a pulse rate based on the result of the application.
(Appendix 10)
A pulse rate calculator that calculates the pulse rate based on the acquired pulse wave signal,
A program for implementing a pulse rate calculator that applies a plurality of types of low-pass filters with different frequencies to attenuate to the pulse wave signal and calculates the pulse rate based on the results of the application.

It should be noted that the programs described in each of the above embodiments and supplementary notes are stored in a storage device or recorded in a computer-readable recording medium. For example, the recording medium is a portable medium such as a flexible disk, an optical disk, a magneto-optical disk, and a semiconductor memory.

Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

In addition, the present invention enjoys the benefit of claiming priority based on the patent application of Japanese Patent Application No. 2019-104970 filed on June 5, 2019 in Japan, and is described in the patent application. The contents are hereby incorporated by reference in their entirety.

100 wearable device 200 sensor board 210 pulse wave sensor 220 processing unit 221 baseline fluctuation removal unit 222 peak detection unit 223 pulse rate calculation unit 224 feedback unit 30 pulse rate calculation device 31 pulse rate calculation unit

Claims (8)

A pulse rate calculation method performed by a pulse rate calculation device that calculates a pulse rate based on an acquired pulse wave signal,
Applying a plurality of types of low-pass filters with different frequencies to be attenuated to the pulse wave signal, and calculating a pulse rate based on the pulse peak detected based on the results of applying the plurality of types of low-pass filters,
When detecting a pulse peak, an estimation range is set based on a reference value, and a pulse peak within the estimation range from the previous peak is detected,
The reference value is a value that is changed based on the pulse rate calculation result.
Pulse rate calculation method. The pulse rate calculation method according to claim 1 ,
Calculating a peak interval when a predetermined value is added to the reference value and a peak interval when a predetermined value is subtracted from the reference value, and determining the estimated range based on the calculated result Sets the pulse rate calculation method. The pulse rate calculation method according to claim 1 or claim 2 ,
A pulse rate calculation method for determining whether a peak pulse exists within the estimated range in a result obtained by applying another low-pass filter when a pulse peak does not exist in the estimated range in a result obtained by applying a certain low-pass filter. The pulse rate calculation method according to any one of claims 1 to 3 ,
A pulse rate calculation method for calculating a pulse rate based on a peak interval between a detected pulse peak and a previous pulse peak. The pulse rate calculation method according to any one of claims 1 to 4 ,
A pulse rate calculation method comprising: applying a predetermined high-pass filter to the pulse wave signal, and then applying a plurality of types of low-pass filters having different frequencies to attenuate. A pulse rate calculation device that calculates a pulse rate based on the acquired pulse wave signal,
a pulse rate calculation unit that applies a plurality of types of low-pass filters with different frequencies to attenuate to the pulse wave signal, and calculates a pulse rate based on a pulse peak detected based on the results of applying the plurality of types of low-pass filters ; have
When detecting a pulse peak, the pulse rate calculator sets an estimation range based on a reference value, detects a pulse peak within the estimation range from the previous peak, and uses it as the reference. value is the value that changes based on the pulse rate calculation result
Pulse rate calculator. A pulse rate calculator that calculates the pulse rate based on the acquired pulse wave signal,
Applying a plurality of types of low-pass filters with different frequencies to be attenuated to the pulse wave signal, and calculating a pulse rate based on the pulse peak detected based on the results of applying the plurality of types of low-pass filters,
When detecting a pulse peak, an estimation range is set based on a reference value, and a pulse peak within the estimation range from the previous peak is detected,
The reference value is a value that is changed based on the pulse rate calculation result.
A program for realizing processing . A pulse rate calculation method performed by a pulse rate calculation device that calculates a pulse rate based on an acquired pulse wave signal,
Applying a plurality of types of low-pass filters with different frequencies to be attenuated to the pulse wave signal, and calculating a pulse rate based on the pulse peak detected based on the results of applying the plurality of types of low-pass filters,
When detecting a pulse peak, an estimation range is set based on a reference value, and a pulse peak within the estimation range from the previous peak is detected,
When detecting a pulse peak based on the results of applying a plurality of types of low-pass filters to the pulse wave signal, if there is no pulse peak within the estimated range in the result of applying a certain low-pass filter, other A pulse rate calculation method for confirming whether a pulse peak exists within the estimated range in the result of applying a low-pass filter .

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