JP5098380B2 - Pulse measuring device and control method thereof - Google Patents

Description

  The present invention relates to an optical pulse measuring device and a control method thereof.

  Conventionally, a pulse measuring device using optical sensing is known. Some optical pulse measuring devices of this type use a filter to extract the pulse component in the measurement signal. For example, the pulse waveform is reproduced by a low-pass filter after the light emitting element is duty driven and amplified on the light receiving side. Technology (for example, refer to Patent Document 1), technology for extracting a pulse waveform by a bandpass filter that passes through a pulse frequency band after light reception (for example, refer to Patent Documents 2 and 3), and modulation components of received light only. There is a technique for demodulating and removing the influence of disturbance light (see, for example, Patent Document 4).

In addition, this type of optical pulse measuring device includes one that detects noise (body motion component) in a measurement signal. For example, two light emitting elements having different wavelengths, first wavelength light, and second wavelength light are included. A technique for determining whether or not the noise level at the time of non-light emission is within an allowable range (see, for example, Patent Document 5), and a plurality of integration means for integrating each received light signal when non-light emission is repeated, and , A filter (0.5 Hz to 2.3 Hz) for passing a pulse signal and a noise component passing filter for passing a signal component having a frequency lower than the pulse, and a pulse wave at the time of noise generation period detection and noise generation detection There is a technique for blocking the output of a filter that allows a signal to pass (see, for example, Patent Document 6). Further, this type of pulse measuring device has been proposed that detects a pulse and body movement using a plurality of sensors (for example, Patent Documents 7, 8, and 9).
Japanese Utility Model Publication No. 53-76697 Japanese Patent Laid-Open No. 2001-145606 JP 2004-202190 A Japanese Patent No. 2,693,958 Japanese Patent No. 3291581 JP-A-1-288230 JP-A-7-88092 JP 2005-28157 A Japanese Patent Laid-Open No. 11-276448

However, in the conventional configuration, a pulse waveform is generated when disturbance light enters due to a change in adhesion with a detection site (blood flow site) due to body movement, or when disturbance light passes through a living body (a wrist or a finger). When there is a noise component (body motion component) close to the frequency, there is a problem that such a noise component cannot be removed.
Moreover, since the technique of the said patent document 5, 7-9 is provided with a some light emitting element, a some light receiving element, or a dedicated body motion sensor, there also exists a problem which the number of components will increase. Further, it is desirable that this type of pulse measuring device be configured to be usable regardless of the presence or absence of external light.

  The present invention has been made in view of the circumstances described above, and has a high pulse detection accuracy even in a situation where external light cannot be received, and a pulse measuring device capable of reducing the number of light emitting elements and light receiving elements, and a control method therefor Is to provide.

In order to solve the above-described problems, the present invention provides a pulse measuring device, wherein a single light-emitting element that emits light at a predetermined time interval toward a detection portion of a living body, and the light can be received through the living body. is disposed, and a single light receiving element for generating a light receiving signal corresponding to the amount of received light, wherein a transparent or semi-transparent light transmitting member extending between the light-receiving element and the biological, pulse rate measuring apparatus around A light-transmitting member that transmits external light of the light and reflects the light by the living body, and allows the light-receiving element to receive the reflected light, and includes the light-emitting frequency of the light-emitting element corresponding to the time interval from the light-receiving signal. A first filter for extracting a first signal component in a first frequency range; a second filter for extracting a second signal component in a second frequency range lower than the frequency of pulsation of the living body from the received light signal; Apply frequency analysis to signal components to When specifying the wave number spectrum and performing frequency analysis on the second signal component to specify the body motion spectrum of the living body, and when the frequency analysis unit cannot specify the body motion spectrum, Pseudo external light that is emitted from the external light instead of the external light is emitted toward the living body via the translucent member, and the reflected light is received by the light receiving element with a light amount corresponding to the body movement of the biological body. When the irradiation unit and the frequency analysis unit specify the body motion spectrum, the pulse that specifies the pulse rate based on the frequency spectrum frequency excluding the body motion spectrum out of the frequency spectrum included in the first signal component And a number specifying unit.

  According to this invention, the first filter can extract the first signal component of only the light emitted from the light emitting element that has passed through the living body to extract the pulsation component and the body motion component that appear in the fluctuation of the blood flow. The body motion component that appears in the change in the amount of received external light can be extracted by the filter. For this reason, the frequency spectrum of the pulse component can be accurately identified from the frequency spectrum included in the first signal component, the pulse detection accuracy is improved, and the number of light emitting elements and light receiving elements is also reduced. In addition, when the body motion spectrum cannot be specified, the light receiving element includes a pseudo external light irradiating unit that emits pseudo external light that can be received in conjunction with the body motion of the living body. The body motion component that appears in the change in the amount of received light can be extracted, and the pulse can be detected with high accuracy.

The said structure WHEREIN: It is preferable that the said light receiving element is provided with the optical filter which suppresses light to the level which the said light receiving element does not electrically saturate by direct sunlight. In the above configuration, the pseudo-external light irradiation unit includes a single pseudo-external light light-emitting element and pseudo-external light that drives the pseudo-external light light-emitting element when the frequency analysis unit cannot identify a body motion spectrum. It is preferable to have a drive unit for use. According to this configuration, since the pulse detection uses only a single light emitting element, a single light receiving element, and a single pseudo external light emitting element, the light emitting element is used despite high pulse detection accuracy. In addition, the number of light receiving elements can be reduced.
The said structure WHEREIN: It is preferable that a said 1st filter is a band pass filter which made the said light emission frequency substantially the center frequency. According to this configuration, it is possible to accurately extract the first signal component of only the light of the light emitting element that has passed through the living body.

Moreover, the said structure WHEREIN: It is preferable that a said 2nd filter is a low-pass filter which allows the body movement frequency range of the said biological body to pass through. According to this arrangement, Ru can retrieve accurately body movement component that appears in the received light quantity changes in ambient light.
Also, it is preferable that the light emitting frequency in a frequency exceeding 1 kHz. According to this configuration, a frequency signal generally used in an infrared home appliance remote controller can be removed by the first filter.

  Further, in the above-described configuration, the detector has a detection unit that detects an envelope of the signal component extracted by the first filter, and the frequency analysis unit performs frequency analysis on the output signal of the detection unit to obtain a pulsation component and a body. It is preferable to specify a frequency spectrum corresponding to the dynamic component. In this case, the detection unit may peak-hold the local maximum values or the local minimum values between the signals extracted by the first filter, and connect them to form the envelope.

Further, in the above configuration, an input selection unit that selectively switches a signal input to the frequency analysis unit between a first signal component extracted by the first filter and a signal component extracted by the second filter. Is preferred. According to this configuration, one frequency analysis unit can be shared as one that performs frequency analysis on the first signal component and the second signal component, and the number of components can be reduced.
In the above structure, the light-emitting element preferably emits infrared light having a single peak wavelength or red light having a single peak wavelength. According to this configuration, it is possible to irradiate light that is difficult to be absorbed in the body.

  Further, in the above configuration, an amplification unit that amplifies the signal components extracted by the first filter and the second filter, and an amplification factor change that variably controls each amplification factor according to the signal level of each amplified signal component It is preferable to provide a part. According to this configuration, it is possible to adjust to a signal level suitable for frequency analysis processing.

The present invention also provides a single light emitting element that emits light at a predetermined time interval toward a detection site of a living body, and a light receiving signal that is disposed so as to be able to receive the light through the living body, and that corresponds to the amount of light received. and a single light receiving element for generating, said a transparent or semi-transparent light transmitting member extending between the light-receiving element and the living body, in the living body by transmitting external light around pulse rate measuring device A method for controlling a pulse measuring device comprising a translucent member that reflects and allows the reflected light to be received by the light receiving element, toward a detection site of a living body, at a predetermined time interval from the single light emitting element The first light receiving element receives the light through the living body, generates a light reception signal corresponding to the amount of light received, and corresponds to the time interval from the light reception signal by the first filter. The first signal component in the first frequency range including the emission frequency The second filter extracts a second signal component in a second frequency range lower than the pulsation frequency of the living body from the light reception signal, and a frequency analysis unit performs frequency analysis on the first signal component to obtain a plurality of frequency components. When specifying the frequency spectrum, performing a process of specifying the body motion spectrum of the living body by performing frequency analysis on the second signal component, when the body motion spectrum cannot be specified, by the pseudo external light irradiation unit, Pseudo external light in place of external light is emitted toward the living body through the translucent member, and the reflected light is received by the light receiving element with a light amount corresponding to the body movement of the living body. When the spectrum is specified, the pulse rate is specified based on the frequency of the spectrum excluding the body motion spectrum among the frequency spectrum included in the first signal component.

  According to this invention, the first filter can extract the first signal component of only the light emitted from the light emitting element that has passed through the living body to extract the pulsation component and the body motion component that appear in the fluctuation of the blood flow. Since the body motion component appearing in the change in the amount of received external light can be extracted by the filter, the frequency spectrum of the pulse component can be accurately identified from the frequency spectrum included in the first signal component, the pulse detection accuracy is improved, and the light emitting element In addition, the number of light receiving elements is also reduced. In addition, when the body motion spectrum cannot be specified, the pseudo external light irradiating unit emits pseudo external light that can be received in conjunction with the body motion of the living body. The body motion component that appears in the change in the amount of received light can be extracted, and the pulse can be detected with high accuracy.

  Further, the present invention is applied to the pulse measuring device and its control method described above, and a control program for carrying out the present invention is distributed to general users via an electric communication line, or such a program is The present invention can also be implemented in such a manner that it is stored in a computer-readable recording medium such as a magnetic recording medium, an optical recording medium, or a semiconductor recording medium and distributed to general users.

  According to the present invention, the first filter extracts only the first signal component of the light emitted from the light emitting element through the living body to extract the pulsation component and the body motion component that appear in the blood flow fluctuation, and the second filter removes the pulsation component and the body motion component. Extract the body motion component that appears in the change in the amount of received light, and if the frequency spectrum of the pulse component cannot be identified from the frequency spectrum included in the first signal component, irradiate pseudo external light that can be received in conjunction with the body motion of the living body Therefore, even in a situation where external light cannot be received, the pulse detection accuracy is high, and the number of light emitting elements and light receiving elements can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a diagram showing a pulse measuring device according to the first embodiment of the present invention. The pulse measuring device 1 is configured in a wristwatch shape, and a wristband (band-like body) that extends from the device body 10 and the 6 o'clock position and the 12 o'clock position of the device body 10 and is wound around a user's arm (wrist). 11 and is configured so that the user can easily wear it when performing exercises such as jogging and running.

The apparatus main body 10 includes a display unit 15 that displays various information such as a pulse rate and time, and a plurality of operation switches 16A, 16B, and 16C that function as operation units for a user to perform various instructions. In addition, various electrical components constituting the biological information detection unit 20 and the like, a battery for supplying operating power of the pulse measuring device 1 and the like are provided.
The operation switch 16A is an operator for starting / stopping pulse measurement. For example, every time the operation switch 16A is operated, the operation mode is switched between a pulse measurement mode (see FIG. 1) and a time display mode. The operation switch 16B is an operation element for instructing start of various setups such as time setting and an operation mode change instruction, and the operation switch 16C is an operation element for clearing the setup and turning on a light (not shown). In the example shown in the figure, the operation switches 16A to 16C are shown as push-type switches, but may be electrostatic switches or touch switches using membrane electrodes.

  The biological information detection unit 20 is disposed on the surface of the user's arm (wrist: blood flow site) X, and includes one light emitting element 21 and one light receiving element 22 as shown in FIG. An optical sensor configured. The light emitting element 21 emits light L1 having a wavelength of 700 nm or more. Specifically, the light emitting element 21 emits infrared light that is not easily absorbed in the body compared to visible light having a single peak wavelength, or red light having a single peak wavelength. LED is applied. As shown in FIG. 2B, the light emitting element 21 emits light L1 toward the user's arm X through a transparent cover (not shown) provided on the back side of the apparatus body 10.

  As the light receiving element 22, a phototransistor capable of receiving light in the wavelength region of the light emitting element 21 and external light L3 (for example, a phototransistor having a light receiving wavelength region of 700 nm or more) is applied. Is provided with an optical filter 22A that suppresses light to a level that does not electrically saturate. The light receiving element 22 is provided at a position where the center of the casing of the apparatus main body 10 is removed as shown in FIG. 2A, and is provided on the back side of the apparatus main body 10 as shown in FIG. The reflected light L2 reflected by the blood vessel K or the like of the arm X is received through the transparent cover (not shown), and a received light signal S1 having a signal level corresponding to the amount of received light is output.

Here, since the light intensity of the light L1 emitted from the light emitting element 21 changes according to the blood flow flowing through the blood vessel K, the amount of reflected light L2 (transmitted light) changes according to the blood flow. In this case, the blood flow in the blood vessel K changes not only due to pulsation but also due to body movement (the movement of the body itself such as arm swinging or the movement of the skin surface that changes when a joint such as a wrist is bent). Therefore, the amount of the reflected light L2 of the light L1 that has reached the blood vessel K changes according to pulsation and body movement.
The reason why the light receiving wavelength region of the light receiving element 22 is set to 700 nm or more is to reliably receive the reflected light of the light L1 of the light emitting element 21 and to be able to receive external light L3 such as sunlight or illumination light. is there. In the present embodiment, a case where the reflection type is configured to receive reflected light will be described. However, the present invention is not limited to this, and in the case where a pulse is detected from a blood vessel such as a finger by the biological information detection unit 20, Or the like).
Further, as described above, in this configuration, since an element capable of receiving the external light L3 is used as the light receiving element 22, a conventional light receiving element that does not include the external light L3 such as sunlight or illumination light in the light receiving wavelength band is used. Compared to the optical pulse measuring device, a general-purpose light receiving element can be widely applied. The light receiving element 22 is not limited to a general-purpose phototransistor but can be a widely distributed photoelectric sensor such as a general-purpose photodiode.

As shown in FIG. 2 (B), the wristband 11 of the pulse measuring device 1 extends to the back side of the device body 10, and includes a back side portion 11A of the device body 10 and a continuous portion 11B continuous to the back side portion 11A. 11C is formed of a translucent member such as a transparent resin or a translucent resin. For this reason, when the pulse measuring device 1 is mounted on the user's arm X, the back side portion 11A and the continuous portions 11B and 11C made of the translucent member are located between the light receiving element 22 and the living body (arm X), External light L3 can be easily introduced between the light receiving element 22 and the living body (arm X). Therefore, as shown in FIG. 2B, when a predetermined gap Y is left between the wristband 11 (biological information measurement unit 20) and the arm X due to the user's arm swinging or the like during running, And external light L3 such as illumination light passes through the gap Y, the back side portion 11A, and the continuous portions 11B and 11C, and is reflected by the arm X or the like and then received by the light receiving element 22. However, even when the gap Y is vacant, the external light L3 may be hardly received by the light receiving element 22 depending on the posture of the pulse measuring device 1 and the incident angle of the external light L3.
On the other hand, when there is almost no gap between the wristband 11 (biological information measuring unit 20) and the arm X, the external light L3 is blocked by the wristband 11 or the case of the apparatus main body 10 and is almost blocked by the light receiving element 22. No light is received. Note that the infrared light component and the red light component of the external light L3 are particularly difficult to be absorbed by the living body such as the arm X, and therefore easily pass through the living body (arm X, surface of the living body (skin etc.)). The light passing through the living body may be received by the light receiving element 22.

That is, the back side portion 11 </ b> A and the continuous portions 11 </ b> B and 11 </ b> C formed by these translucent members function as the external light introducing portion 30 that introduces the external light L <b> 3 to the light receiving surface side of the light receiving element 22. In the following description, these will be referred to as the external light introducing unit 30.
The external light introduction unit 30 is not limited to the translucent member, and may be an opening formed in the wristband 11. In short, the light receiving element is configured so that the amount of received external light L3 varies depending on body movement. If it can be introduced into the system 22, any design is possible. In addition, the wristband 11 may be a colored member other than the external light introduction unit 30 or may be a translucent member other than the external light introduction unit 30.

As described above, in the present embodiment, the external light introduction unit 30 is provided so that the external light L3 can be received by the light receiving element 22 according to body movement. However, in an environment where there is almost no sunlight or illumination light, for example, at night time or on a cloudy day, the light receiving element 22 hardly receives the external light L3. For this reason, in this configuration, as shown in FIGS. 2A and 2B, a pseudo external light irradiation unit 25 that irradiates light L5 (hereinafter referred to as pseudo external light) instead of the external light L3 is provided. Provided.
More specifically, as shown in FIG. 2A, the pseudo external light irradiation unit 25 has one pseudo external light emitting element 26 in the apparatus body 10, and the pseudo external light emitting element 26 includes The LED that emits pseudo external light L5 that can be received by the light receiving element 22 is applied, specifically, an LED that emits the same light as the light emitting element 21 (light of 700 nm or more), more specifically, a single LED. An LED that emits infrared light that is not easily absorbed in the body compared to visible light having one peak wavelength or red light having a single peak wavelength is used.

The pseudo-external light emitting element 26 is disposed close to the outer peripheral portion of the apparatus main body 10, thereby being positioned near the entrance of the external light L 3 on the back side of the apparatus main body 10. The pseudo external light emitting element 26 emits pseudo external light L5 toward the user's arm X via the transparent cover on the back side of the apparatus main body 10 and the external light introducing unit 30.
The emission direction of the pseudo external light L5 is directed to the light receiving element 22 side, and the incident angle with respect to the arm X is set large. For this reason, the pseudo external light L5 is incident on the arm X at substantially the same incident angle as the external light L3, is substantially totally reflected on the surface of the arm X, and has a predetermined gap Y between the wristband 11 and the arm X. The amount of light reaching the light receiving element 22 changes according to the change. Thereby, the pseudo external light irradiation unit 25 irradiates the pseudo external light L5 that the light receiving element 22 can receive in conjunction with the body movement of the living body.

  FIG. 3 is a block diagram of the pulse measuring device 1, and FIG. 4 is a diagram showing a circuit configuration thereof. In FIG. 3, the light emission control unit 50 performs light emission control of the light emitting element 21. The light emission control unit 50 divides an oscillation signal (for example, 32 kHz) of an oscillation circuit (not shown) by 2 kHz (1/16 division). When a signal is input, the driving power is supplied to the light emitting element 21 when the 2 kHz signal is at the H level, and the driving power supply is stopped when the 2 kHz signal is at the L level, and thereby a time corresponding to a 2 kHz duty ratio of 50%. Repeat lighting / extinguishing at intervals. That is, in this pulse measuring device 1, 2 kHz is set as the light emission frequency (also referred to as intermittent drive frequency) that defines the time interval of light emission.

  The current-voltage conversion unit 51 performs current / voltage conversion on the light reception signal S1 output from the light receiving element 22, and connects the output of the operational amplifier 51A and the input − through a resistor 51B as shown in FIG. A capacitor 51C is connected in parallel, a current proportional to the amount of received light is converted into a voltage, amplified by an operational amplifier 51A, and output.

The light reception signal S2 converted by the current-voltage conversion unit 51 is output to a band-pass filter unit (first filter) 52 and a low-pass filter unit (second filter) 53, respectively.
The band pass filter unit 52 extracts a signal component (first signal component) in a first frequency range including the light emission frequency (2 kHz) from the light reception signal S2 output from the current-voltage conversion unit 51. More specifically, the band-pass filter unit 52 uses the emission frequency as the center frequency (f0) and has a higher frequency range than the low frequency range that passes through the low-pass filter unit 53 (1 kHz or more in this configuration). The signal component of is passed. As a result, the signal component of the light passing through the living body (the reflected light L2 of the light L1) can be extracted. In other words, the signal component whose amplitude level varies according to the blood flow variation (variation due to pulsation and body movement). Can be taken out.

As shown in FIG. 4, the band-pass filter unit 52 connects the output of the operational amplifier 52A and the input − through the resistor 52B, and connects through the capacitors 52C and 52D, and on the input side to the input −. It is composed of a multiple feedback active filter circuit to which resistors 52E and 52F are connected. For this reason, compared with the case where it comprises with a passive filter circuit, there exists an advantage that the freedom degree of the frequency characteristic obtained is high and can be amplified.
Here, the reason why the pass frequency of the band pass filter unit 52 is set to 1 kHz or more is to remove a frequency signal (corresponding to a noise component) of 1 kHz or less that is generally used in an infrared home appliance remote controller.

The low-pass filter unit 53 extracts a signal component in the second frequency range lower than the pulsation frequency from the light reception signal output from the current-voltage conversion unit 51. In other words, the light-receiving element according to the body motion 22 is configured as a filter capable of extracting a body motion component due to the external light L3 incident on the lens 22.
Here, the body motion component (the body motion such as arm swing during walking or running or the movement of the skin surface that changes when the wrist joint is bent) is usually greater than 0 Hz and less than or equal to 10 Hz. Therefore, the low-pass filter unit 53 is configured as a filter having a cutoff frequency (fc) of 10 Hz, for example. As shown in FIG. 4, the low-pass filter unit 53 is composed of an active filter circuit in which resistors 53A and 53B, capacitors 53C and 53D, and an operational amplifier 53E are combined. The obtained frequency characteristics have a high degree of freedom and can be amplified.

  As shown in FIG. 3, an amplification unit (first amplification unit) 55 whose amplification factor can be changed by an amplification factor changing unit 54 and a detection unit (first detection unit) are arranged at the subsequent stage (output side) of the bandpass filter unit 52. 56) are connected in order, and an amplification unit (second amplification unit) 58 whose amplification factor can be changed by the amplification factor changing unit 57 is connected to the subsequent stage (output side) of the low-pass filter unit 53.

  The amplifying unit 55 and the amplification factor changing unit 54 are for amplifying the received light signal S3 having passed through the band-pass filter unit 52 to a signal level suitable for arithmetic processing (frequency analysis processing) by the arithmetic processing unit 60. . As shown in FIG. 4, the amplifying unit 55 and the amplification factor changing unit 54 switch the resistors 54A, 55C, and 54C in a feedback path that connects the output and the input − of the operational amplifier 55C in which the resistors 55A and 55B are arranged at the front and rear. The circuit is configured to be connectable via the elements 54D, 54E, and 54F, and the amplification factor is changed by controlling the on / off of each of the switching elements 54D to 54F under the control of the arithmetic processing unit 60.

  The detector 56 detects the envelope of the received light signal S3 amplified by the amplifier 55. As shown in FIG. 4, the input signal is passed through a Schottky diode 56A, and a parallel circuit of a resistor 56B and a capacitor 56C. The circuit received in is applied. By appropriately designing the time constants of the resistor 56B and the capacitor 56C, the output waveform can be made close to the envelope of the input waveform.

  Instead of the detection unit 56, a detection unit may be provided for peak-holding the local maximum values or the local minimum values of the light reception signal S3 and connecting them to detect the envelope. In this case, the detection unit includes a digital memory scope that acquires waveform data obtained by analog-to-digital conversion of the received light signal S3, and peaks and holds the local maximum values or the local minimum values of the waveform data acquired in the digital memory scope. What is necessary is just to acquire the obtained envelope. In this way, by obtaining an envelope connecting the maximum values or the minimum values, the influence of the noise component can be reduced and the envelope can be detected. In this case, the envelope does not include the waveform of the pulsation itself, but includes a waveform of ½ frequency of the pulsation.

  The amplifying unit 58 and the amplification factor changing unit 57 are for amplifying the received light signal S4 that has passed through the low-pass filter unit 53 to a signal level suitable for arithmetic processing (frequency analysis processing) by the arithmetic processing unit 60. Yes, the same circuit as the amplifying unit 55 and the amplification factor changing unit 54 is applied. In other words, as shown in FIG. 4, the amplifying unit 58 and the amplification factor changing unit 57 are provided with resistors 57A, 57C, and 57C in a feedback path that connects the output and the input − of the operational amplifier 58C in which resistors 58A and 58B are arranged at the front and rear, respectively. The circuit is configured to be connectable via the switching elements 57D, 57E, and 57F, and the amplification factor is changed by controlling the on / off of each of the switching elements 57D to 57F under the control of the arithmetic processing unit 60. .

The input selection unit 61 switches either the light reception signal S3 amplified by the amplification unit 55 or the light reception signal S4 amplified by the amplification unit 58 to the A / D conversion unit 62 under the control of the arithmetic processing unit 60. As shown in FIG. 3, switching elements 61A and 61B are arranged on the output sides of the amplifying units 55 and 58, respectively, and the A / D input selection from the arithmetic processing unit 60 is performed on one switching element 61A. A circuit for switching on / off by applying the signal level of the A / D input selection signal SS inverted by an inverter 61C is applied to the other switching element 61B.
The A / D conversion unit 62 receives either the envelope signal S3A or the light reception signal S4 of the light reception signal S3, performs analog-digital conversion, and outputs it to the arithmetic processing unit 60.

  The pseudo external light irradiation unit 25 includes a pseudo external light emitting element 26 and a pseudo external light drive unit 27, and the pseudo external light drive unit 27 emits light for pseudo external light under the control of the arithmetic processing unit 60. The light emission control of the element 26 is performed. As shown in FIG. 4, the pseudo-external light drive unit 27 connects the collector of the transistor 27A to the pseudo-external light light-emitting element 26 via a resistor 27B, grounds the emitter of the transistor 25A, and connects the resistance to the base. A circuit having a configuration in which a control signal (signal to turn on / off) from the arithmetic processing unit 60 is input via the 27C is applied, and the pseudo external light emitting element 26 is selectively driven based on the control signal.

  The arithmetic processing unit 60 includes a computer configuration including a CPU, a ROM, and a RAM (in this example, including an FFT RAM 1 and an FFT RAM 2), and the CPU executes a control program stored in the ROM. , Such as a frequency analysis unit that performs frequency analysis processing (FFT processing) of input data, a pulse rate specification unit that specifies a pulse rate based on the frequency analysis result, and a pulse measurement such as processing that causes the display unit 15 to display the specified pulse rate It functions as a control unit that controls each unit of the device 1.

  In the present embodiment, a case where the arithmetic processing unit 60 functions as a frequency analysis unit, a pulse rate specifying unit, and a control unit by software processing will be described. However, the present invention is not limited to this, and the frequency analysis unit, the pulse rate specifying unit, and You may comprise by the hardware circuit which comprises a control part. The arithmetic processing unit 60 also incorporates a clock circuit that measures time based on a frequency-divided signal (1 Hz signal) of an oscillation signal (not shown) of an oscillation circuit. Since a known configuration may be applied to the configuration of the timepiece circuit, detailed description is omitted.

Next, the operation | movement at the time of the pulse measurement of this pulse measuring device 1 is demonstrated. FIG. 5 is a flowchart showing the operation in this case.
When the user operates the operation switch 16A to instruct the start of pulse measurement, first, a CPU in the arithmetic processing unit 60 (hereinafter referred to as a control unit) outputs an output (this book) obtained by dividing an oscillation signal of an oscillation circuit (not shown). In the example, an interrupt of 32 Hz signal) is permitted (step SP 1), and the A / D conversion unit 62 is taken in and the input selection unit 61 performs input switching using the 32 Hz interrupt as a trigger. In addition, the control unit sets the variable N to a value of 0 (step S2), and then causes the light emission control unit 50 to start light emission control of the light emitting element 21 at a time interval of 2 kHz (light emission frequency) with a duty ratio of 50%.

For this reason, the light receiving signal S1 is output from the light receiving element 22, and is converted into a current voltage by the current-voltage converting unit 51, and a light receiving signal S2 that is a modulated wave of 2 kHz is output as shown in FIG. Then, the light reception signal S2 passes through the band-pass filter 52 having a center frequency of 2 kHz, so that a light reception signal S3 indicating a modulation component of 2 kHz is output as shown in FIG. 6B. Next, when the detection unit 56 performs detection processing on the light reception signal S3, an envelope signal S3A indicating an envelope of the light reception signal S3 is output as shown in FIG. 6C.
The waveform of the envelope signal S3A includes information on the pulsation component (pulse waveform) and the body motion component (body motion waveform).

In addition, the light reception signal S2 passes through the low-pass filter unit 53 that passes 10 Hz or less, thereby obtaining the light reception signal S4 from which the pulsation component has been removed. The waveform of the light reception signal S4 includes the body motion component and Information on noise components (such as disturbance light components that do not depend on body movement) is included.
Next, after executing the process of step S2, the control unit sets the A / D input selection signal SS to the H level and waits until the 32 Hz interrupt flag is turned on (step SP4). The 32 Hz interrupt flag is a flag for determining whether or not one period (1/32 second) of the 32 Hz interrupt signal has elapsed. In other words, the 32 Hz interrupt flag is taken in by the A / D converter 62. This is a flag for detecting the timing of input switching.

When the A / D input selection signal SS is set to the H level, the switching element 61A of the input selection unit 61 is set to an open state and the switching element 61B is set to a closed body, so that the envelope signal S3A is It is output to the A / D converter 62, where it is analog-digital converted and output to the arithmetic processor 60.
When the 32 Hz interrupt flag is turned on (step SP5: YES), the control unit clears the 32 Hz interrupt flag (step SP6) and stores digital data (envelope waveform data) in the FFT RAM 1 (step SP6). SP7).

  Subsequently, the control unit switches the A / D input selection signal SS to the L level, switches the switching element 61A of the input selection unit 61 to the closed state, and switches the switching element 61B to the open state. For this reason, the received light signal S4 that has passed through the low-pass filter unit 53 is input to the A / D conversion unit 62, converted from analog to digital, and output to the arithmetic processing unit 60. When the 32 Hz interrupt flag is turned on (step SP8: YES), the control unit clears the 32 Hz interrupt flag (step SP9) and stores the digital data (waveform data of the light reception signal S4) in the FFT RAM 2 ( Step SP10).

  Next, the control unit adds 1 to the variable N (step SP11), and determines whether or not the variable N has reached the value 256 (step SP12). At this time, if the value 256 has not been reached (step SP12: NO), the process proceeds to step SP3, and the acquisition of the waveform data of the envelope and the acquisition of the waveform data of the light reception signal S4 are started again. As a result, the acquisition of these data is repeated until the variable N reaches the value 256, and the acquisition of the data is repeated until the waveform data of each 16 Hz 256 points is stored in the FFT RAM 1 and the FFT RAM 2.

Subsequently, when the variable N reaches the value 256 (step SP12: YES), the control unit performs FFT (Fast Fourier Transform) on the waveform data (the waveform data of the envelope of the light reception signal S3) stored in the FFT RAM 1. ) By executing the process (frequency analysis) (step SP13), as shown in FIG. 7A, the first frequency analysis result that can specify a plurality of frequency spectra (local peaks) included in the waveform is obtained. obtain.
Next, the control unit performs similar FFT (Fast Fourier Transform) processing (frequency analysis) on the waveform data (waveform data of the light reception signal S4) stored in the FFT RAM 2 (step SP14), As shown in FIG. 7B, a second frequency analysis result that can identify one or a plurality of frequency spectra (local peaks) included in the waveform is obtained.

Here, as described above, the waveform data stored in the FFT RAM 1 includes information on the pulsation component (pulse waveform) and the body motion component (body motion waveform). It can be seen that the two frequency spectra f1 and f2 correspond to a pulsation component and a body motion component. However, it is difficult to specify which frequency spectrum f1, f2 is a pulsating component only with this information.
On the other hand, since the waveform data stored in the FFT RAM 2 includes the body motion component and the noise component and does not include the pulsation component (pulse waveform) as described above, the large waveform shown in FIG. It can be seen that the frequency spectra f3, f4, and f5 are either body motion components or noise components.

  For this reason, the control unit compares the first frequency analysis result and the second frequency analysis result, thereby obtaining the frequency spectra f2 and f3 of the same frequency included in both frequency analysis results as body motion components (body Dynamic spectrum) and is included in the first frequency analysis result but is not included in the second frequency analysis result, and a process of specifying the frequency spectrum f1 as a pulsation component (pulsation spectrum) is executed (step SP15). .

  Subsequently, the control unit determines whether or not the body motion component has been detected (step SP16). If the body motion component has been detected (step SP16: YES), the frequency of the frequency spectrum f1 is determined per minute. The pulse rate is calculated in terms of the number of amplitudes, the calculated pulse rate is displayed on the display unit 15 (step S17), and the process proceeds to step SP2.

On the other hand, when the body movement component cannot be detected (step SP16: NO), the control unit determines whether or not the pseudo external light irradiation unit 25 is irradiating the pseudo external light L5 (step SP18), and pseudo external light. If the irradiation is not in progress (step SP18: NO), the pseudo-external light driving unit 27 drives the pseudo-external light-emitting element 26 to irradiate the pseudo external light L5 (step SP19). And a control part transfers to the process of step SP2 after pseudo external light L5 irradiation, and performs the redetection process (steps SP2-SP17) of a pulse rate.
For this reason, in the situation where the external light L3 cannot be received in the night time zone or on a cloudy day, the pseudo external light L5 is used instead of the external light L3, and the second frequency analysis result corresponds to the body motion component. Frequency spectrum (corresponding to the above f3) appears. Therefore, the control unit can detect the body motion component by comparing the first frequency analysis result and the second frequency analysis result, and can detect the pulse rate with high accuracy.

If it is determined in step S18 that pseudo-external light irradiation is being performed (step SP18: YES), the control unit proceeds to the process in step SP2, and executes the processes in steps SP2 to SP16 again. Re-detect the pulse rate. As a result, if no body motion component happens to be detected, the pulse rate can be accurately detected when the body motion component is detected next time.
In this flowchart, the case where the pulse rate re-detection process is executed when the body motion component cannot be acquired despite the irradiation of the pseudo external light L5 (step SP18: YES) is described. In such a case, since it can be determined that there is no body movement, that is, a situation where the user is not exercising, the pulse rate is estimated based on only the first frequency analysis result and the pulse rate is displayed. You may make it do.

  Specifically, for example, when the frequency spectrum (local peak) obtained from the first frequency analysis result is one and within the frequency range of the pulse, the frequency spectrum is identified as the pulsation component. There is a method of calculating and displaying the pulse rate from the frequency spectrum. In addition, for example, when there are a plurality of frequency spectra (local peaks) obtained from the first frequency analysis result, the frequency spectrum within the frequency range of the pulse is extracted from these frequency spectra, There is a method of calculating and displaying the pulse rate from this frequency spectrum.

  The operation described above is continuously repeated until a stop of pulse measurement is instructed by the user, and the real-time pulse rate can be displayed on the display unit 15. The above is the operation at the time of pulse measurement. As described above, when the frequency spectra f2 and f3 can be specified as body motion components and the frequency spectrum f1 as pulsation components, the frequency spectra f4, f5, and f6 can be specified as noise components. For this reason, by storing these noise components and then performing a learning process for estimating noise components, it is possible to help improve detection accuracy thereafter.

  On the other hand, when the stop of pulse measurement is instructed by the user and the start of time display is instructed, the control unit acquires the time measured by the clock circuit and displays it on the display unit 15. In this case, driving of the light emitting element 21, signal output from the light receiving element 22 to the current-voltage conversion unit 51, driving of the pseudo external light emitting element 26, and the like are stopped to save power consumption. Yes.

  As described above, the pulse measuring device 1 of the present embodiment receives a single light emitting element 21 that irradiates the light L1 at a predetermined time interval (corresponding to the light emission frequency) and the light L1 through the living body. At the same time, a single light receiving element 22 capable of receiving external light L3 incident from the outside through a gap Y formed between the arm X and the biological information measuring unit 20 by body movement, and the light receiving element 22 outputs the light. A band-pass filter unit 52 for extracting a first signal component in a first frequency range having a light emission frequency corresponding to the time interval as a center frequency from the received light signal, and a second frequency range lower than the pulsation frequency from the received light signal. And a low-pass filter unit 53 for extracting the second signal component of the signal, the band-pass filter unit 52 extracts the signal component of only the light that has passed through the living body (reflected light L2 of the light L1), and fluctuations in blood flow. The pulse that appears in It is possible to take out the component and the body motion component, by a low-pass filter unit 53 can take out the body motion components appearing in the received light quantity changes in external light L3.

  Therefore, the frequency spectra f1 and f2 corresponding to either the pulsation component or the body motion component are identified from the signal component that has passed through the band pass filter unit 52, and the body from the signal component that has passed through the low pass filter unit 53. An arithmetic processing unit 60 for specifying the frequency spectrum of the dynamic component f3 is provided, and the arithmetic processing unit 60 specifies the frequency spectrum f1 included in the first signal component but not included in the second signal component as the pulsation spectrum. Since the pulse rate is calculated based on the frequency of the pulsation spectrum, the pulsation component f1 and the body motion component f2 (= f3) can be detected with high accuracy, and the pulse detection accuracy and the body motion detection accuracy can be improved. it can.

Moreover, in this configuration, since the pseudo external light irradiation unit 25 that irradiates the pseudo external light L5 instead of the external light L3 is provided, the pseudo external light can be used when the arithmetic processing unit 60 cannot identify the body motion component (body motion spectrum). By irradiating the pseudo external light L5 from the irradiation unit 25, a body motion component (body motion spectrum) can be extracted by the low-pass filter unit 53 even in a situation where the external light L3 cannot be received. Therefore, the pulse rate can be detected with high accuracy regardless of the time zone and place.
Furthermore, in this configuration, the living body information detection unit 20 only needs to include one light emitting element 21 and one light receiving element 22, respectively. In addition, the pseudo external light irradiation unit 25 includes one light emitting element 26 for pseudo external light. Since it only needs to be provided, the number of light emitting elements and light receiving elements can be reduced although the pulse detection accuracy is higher than the conventional one.

Further, in this configuration, the wristband 11 is provided with the external light introduction unit 30 that introduces the external light L3 so that the amount of incident external light incident on the light receiving element 22 is changed by the user's body movement. The external light L3 can be more reliably received with the amount of incident light corresponding to the body movement.
It is also possible to adopt a configuration in which the external light introducing unit 30 is not provided. Even in a configuration in which the external light introducing unit 30 is not provided, in a body-mounted type such as the wristwatch-type pulse measuring device 1, a predetermined gap Y is provided between the biological information measuring unit 20 and the arm X by the user's movement such as arm swinging. This is because the external light L3 that has passed through the gap Y may be received by the light receiving element 22 because it is vacant. In addition, since the external light L3 may reach the light receiving element 22 through the living body (arm X, biological surface (skin etc.)), the external light L3 may be received by the light receiving element 22 due to this. . However, it is clear that the provision of the external light introducing portion 30 is more reliable in order for the light receiving element 22 to reliably receive the external light L3.

  Further, in this configuration, as shown in FIG. 2A, the center of gravity of the apparatus main body 10 is shifted from the center position by installing the light receiving element 22 at a position away from the center of the apparatus main body 10. Accordingly, a gap Y is easily formed between the biological information measuring unit 20 and the arm X due to a user's movement such as swinging the arm, and the external light L3 is easily received by the light receiving element 22 to improve detection accuracy of body movement. be able to.

Furthermore, in this configuration, since the first filter that extracts only the signal component of the light passing through the living body (the reflected light L2 of the light L1) is configured in the band-pass filter unit 52, the high-frequency component corresponding to the noise component is removed in advance. It is possible.
In addition, since the input selection unit 61 that switches and outputs the first signal component that has passed through the band-pass filter unit 52 and the second signal component that has passed through the low-pass filter unit 53 to the A / D conversion unit 62 is provided. The A / D conversion unit 62 and the arithmetic processing unit 60 (frequency analysis unit) used for signal processing of these signal components can be shared by one, and the number of components can be reduced accordingly.
In the above-described embodiment, the case where the light emission frequency is 2 kHz is exemplified, but the present invention is not limited to this. For example, when a crystal oscillation circuit generally used for a watch is used as the oscillation circuit, it is preferable to use a frequency that is an integer multiple of 2048 Hz or 1024 Hz, which is the frequency division frequency.

Second Embodiment
FIG. 8 is a block diagram of the pulse measuring device 1 according to the second embodiment. The pulse measuring device 1 includes an A / D conversion unit 62A dedicated to a signal (envelope signal S3A) that has passed through the band-pass filter unit 52 and a first frequency analysis unit (FFT) 70A, and a low-pass filter unit. The pulse measuring device 1 according to the first embodiment is different from the pulse measuring device 1 according to the first embodiment in that an A / D conversion unit 62B and a second frequency analysis unit (FFT) 70B dedicated to the signal (light reception signal S4) that has passed through 53 are provided. Since the configuration other than this is substantially the same as that of the first embodiment, the same reference numerals are given, and redundant description is omitted.

  The A / D conversion unit 62A inputs the envelope signal S3A of the received light signal S3 that passes through the bandpass filter unit 52 and is output from the detection unit 56, and analog-digital converts this to the first frequency analysis unit 70A. Output. Then, the first frequency analysis unit 70A performs an FFT (Fast Fourier Transform) process on the input envelope signal S3A data, and outputs the frequency analysis result to the arithmetic processing unit 60.

  The A / D conversion unit 62B receives the received light signal S4 that has passed through the low-pass filter unit 53, converts the received signal S4 from analog to digital, and outputs the converted signal to the second frequency analysis unit 70B. Then, the second frequency analysis unit 70B performs an FFT (Fast Fourier Transform) process on the input data of the received light signal S4, and outputs the frequency analysis result to the arithmetic processing unit 60.

  As described above, in the present embodiment, the A / D conversion unit 62A and the first frequency analysis unit 70A dedicated to the signal that has passed through the bandpass filter unit 52 are provided, and the A dedicated to the signal that has passed through the low-pass filter unit 53 is provided. Since the A / D conversion unit 62A and the second frequency analysis unit 70B are provided, the frequency analysis processing with a large amount of calculation can be performed by the dedicated frequency analysis units 70A and 70B, thereby reducing the burden on the arithmetic processing unit 60 (CPU). can do. As a result, it is possible to employ a CPU having a relatively low calculation capability for the CPU in the calculation processing unit 60, and it is possible to use general-purpose frequency analysis IC chips as the frequency analysis units 70A and 70B.

<Third Embodiment>
FIG. 9 is a block diagram of the pulse measuring device 1 according to the third embodiment. The pulse measuring device 1 is an optical pulse measuring device that irradiates the user's finger X2 with the light L1 of the light emitting element 21 and receives the reflected light L2 with the light receiving element 22, and includes an external light introducing unit 30, The difference from the pulse measuring device 1 according to the second embodiment is that the amplification factor changing units 54 and 57 are not provided. Since the other configuration is substantially the same as that of the second embodiment, the same reference numerals are given, and redundant description is omitted.
In this pulse measuring device 1, the amplification factors 55 and 58 are fixed to a predetermined constant value. This fixed value is set to a value that is most appropriate when pulse waves are measured in various environments. According to this configuration, it is possible to reduce the number of components compared to the first embodiment and the second embodiment because the amplification factor changing unit or the like for changing the amplification factor of the amplification units 55 and 58 is not provided. The burden on the arithmetic processing unit 60 (CPU) can be reduced.

In addition, this invention is not limited to the above-mentioned embodiment, The deformation | transformation in the range which can achieve the objective of this invention, improvement, etc. are included in this invention.
For example, in the above-described embodiment, the case where the control program for executing the pulse measurement process is stored in the pulse measurement device 1 in advance has been described. However, the control program is stored in a magnetic recording medium, an optical recording medium, a semiconductor, and the like. It may be stored in a computer-readable recording medium such as a recording medium, and the computer may read and execute the control program from the recording medium. The control program may be downloaded from a distribution server on the communication network.
Moreover, although the above-mentioned embodiment demonstrated the case where this invention was applied to a wristwatch-type pulse measuring device, it is not restricted to this. For example, an optical sensor unit (corresponding to a biological information detection unit) provided with a light emitting element 21 and a light receiving element 22 is attached to a blood flow site of a living body such as a person or an animal, and the other configurations are separate pulses. It can be widely applied to measuring devices and the like. In addition, the blood flow site for pulse detection is not limited to the wrist and fingers, but may be the ear.

It is a figure which shows the pulse measuring device which concerns on 1st Embodiment of this invention. (A) is a top view which shows the layout of the light emitting element of a pulse measuring device, a light receiving element, and the light emitting element for pseudo external light, (B) is the sectional side view. It is a block diagram of a pulse measuring device. It is a figure which shows the circuit structure of a pulse measuring device. It is a flowchart which shows the operation | movement at the time of a pulse measurement. (A)-(D) are figures which show the signal waveform of each part in a pulse measuring device. (A) is a figure which shows the frequency analysis result of the signal which passed the band pass filter part, (B) is a figure which shows the frequency analysis result of the signal which passed the low-pass filter part. It is a block diagram of the pulse measuring device concerning a 2nd embodiment of the present invention. It is a block diagram of the pulse measuring device concerning a 3rd embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Pulse measuring device, 10 ... Apparatus main body, 11 ... Wristband, 15 ... Display part, 20 ... Biological information detection part, 21 ... Light emitting element, 22 ... Light receiving element, 30 ... External light introduction part, 50 ... Light emission control part , 51 ... current-voltage converter, 52 ... band-pass filter (first filter), 53 ... low-pass filter (second filter), 54, 57 ... amplification factor changing unit, 55, 58 ... amplifying unit, 56 ... detection unit, 60 ... calculation processing unit, 61 ... input selection unit, 62 ... A / D conversion unit, f1-f6 ... frequency spectrum.

Claims (12)

A single light emitting element that emits light at a predetermined time interval toward a detection site of a living body,
A single light receiving element that is arranged to receive the light via the living body and generates a light reception signal corresponding to the amount of light received;
Wherein a transparent or semi-transparent light transmitting member extending between the light-receiving element and the living body by transmitting external light around pulse rate measuring device is reflected by the living body, the reflected light, the light receiving A translucent member that allows the element to receive light;
A first filter for extracting a first signal component in a first frequency range including a light emission frequency of the light emitting element corresponding to the time interval from the light reception signal;
A second filter for extracting a second signal component in a second frequency range lower than the pulsation frequency of the living body from the received light signal;
A frequency analysis unit that performs frequency analysis on the first signal component to identify a plurality of frequency spectra, and performs a frequency analysis on the second signal component to identify a body motion spectrum of the living body;
When the frequency analysis unit cannot identify a body motion spectrum, pseudo external light serving as a substitute for the external light is emitted toward the living body through the translucent member, and the reflected light is emitted from the body motion of the living body. A pseudo external light irradiator that causes the light receiving element to receive light with a light amount according to
A pulse rate specifying unit for specifying a pulse rate based on the frequency of the frequency spectrum excluding the body motion spectrum out of the frequency spectrum included in the first signal component when the frequency analysis unit specifies the body motion spectrum; A pulse measuring device comprising: In the pulse measuring device according to claim 1,
The pulse measuring device, wherein the light receiving element includes an optical filter that suppresses light to a level at which the light receiving element is not electrically saturated even by direct sunlight. In the pulse measuring device according to claim 1 or 2,
The pseudo external light irradiating unit includes a single pseudo external light emitting element, and a pseudo external light driving unit that drives the pseudo external light emitting element when the frequency analysis unit cannot identify a body motion spectrum. A pulse measuring device characterized by comprising: In the pulse measuring device according to any one of claims 1 to 3,
The pulse measuring device according to claim 1, wherein the first filter is a band-pass filter having the emission frequency as a substantially central frequency. In the pulse measuring device according to any one of claims 1 to 4,
The pulse measuring device according to claim 2, wherein the second filter is a low-pass filter that allows the body motion frequency range of the living body to pass through. In the pulse measuring device according to any one of claims 1 to 5,
A pulse measuring apparatus characterized in that the emission frequency is set to a frequency exceeding 1 kHz. In the pulse measuring device according to any one of claims 1 to 6,
A detection unit that detects an envelope of the signal component extracted by the first filter, and the frequency analysis unit performs frequency analysis on the output signal of the detection unit to correspond to a pulsation component and a body motion component. A pulse measuring device characterized by specifying a spectrum. In the pulse measuring device according to claim 7,
The pulse detector according to claim 1, wherein the detection unit peaks and holds local maximum values or local minimum values between signals extracted by the first filter and connects them to form the envelope. In the pulse measuring device according to any one of claims 1 to 8,
An input selection unit that selectively switches a signal input to the frequency analysis unit between a first signal component extracted by the first filter and a second signal component extracted by the second filter. Pulse measuring device. In the pulse measuring device according to any one of claims 1 to 9,
The pulse measuring device, wherein the light emitting element emits infrared light having a single peak wavelength or red light having a single peak wavelength. In the pulse measuring device according to any one of claims 1 to 10,
Further comprising an amplifier unit for amplifying each of said first filter and the signal component second filter is extracted, and the amplification factor changes section for variably controlling the respective amplification factor in accordance with a signal level of each signal component of the amplified A pulse measuring device characterized by the above. A single light emitting element that irradiates light at a predetermined time interval toward the detection site of the living body, and a single light emitting element that is arranged so as to be able to receive the light through the living body and generates a light reception signal corresponding to the amount of light received a light receiving element, wherein a transparent or semi-transparent light transmitting member extending between the light-receiving element and the living body, it is reflected by the living body by transmitting external light around pulse rate measuring device, the reflected light A method for controlling a pulse measuring device comprising a translucent member that allows the light receiving element to receive light,
Aiming at a detection site of a living body, irradiating light from the single light emitting element at a predetermined time interval,
The light is received through the living body by the single light receiving element, and a light reception signal corresponding to the amount of light received is generated,
The first filter extracts a first signal component in a first frequency range including a light emission frequency corresponding to the time interval from the light reception signal,
The second filter extracts a second signal component in a second frequency range lower than the pulsation frequency of the living body from the light reception signal,
The frequency analysis unit performs frequency analysis on the first signal component to specify a plurality of frequency spectra, and performs frequency analysis on the second signal component to specify the body motion spectrum of the living body,
When the body motion spectrum cannot be specified, the pseudo external light irradiation unit emits pseudo external light instead of the external light toward the living body through the translucent member, and the reflected light is emitted from the living body. The light receiving element receives light with a light amount corresponding to the body movement of
When the body motion spectrum is specified, the pulse rate is specified based on the frequency of the spectrum excluding the body motion spectrum out of the frequency spectrum included in the first signal component. Method.

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