JP6079075B2 - Pulse measuring device, pulse measuring method and pulse measuring program - Google Patents

Description

  The present invention relates to a pulse measuring device, and more particularly to a pulse measuring device that detects the pulsation of a blood vessel of a measurement subject and measures the pulse rate.

  The present invention also relates to a pulse measuring method and a pulse measuring program, and more particularly to a pulse measuring method and a pulse measuring program for detecting a pulse of a blood vessel of a measurement subject and measuring the pulse rate.

  Conventionally, as a device for measuring a subject's pulse, a belt to which an electrocardiographic sensor is attached is wound around the chest of the subject and the heartbeat of the subject is measured electrocardiographically. Thus, there is a device for measuring the pulse rate (heart rate) of the person being measured.

  In addition, while the above-described device detects the heartbeat of the measurement subject electrocardiographically, there is also a device that measures the pulse rate by detecting the pulsation of the blood vessel of the measurement subject non-electrocardiographically.

  As the latter device, for example, there is a device that measures the pulse rate of the measurement subject by photoelectrically detecting the pulsation of the subcutaneous blood vessel of the measurement subject using a photoelectric sensor (for example, Patent Document 1 (Japanese Patent Laid-Open No. 10-234684).

  In such a latter apparatus, a signal (pulse wave signal) representing the pulsation of the subcutaneous blood vessel of the measurement subject is acquired, and the pulse rate is measured based on the periodicity of the time fluctuation of the pulse wave signal. .

Japanese Patent Laid-Open No. 10-234684

  However, in a device that measures the pulse rate of the measurement subject by detecting the pulsation of the subcutaneous blood vessel of the measurement subject non-electrocardially, for example, photoelectrically, the measurement subject moves, for example, It is difficult to correctly measure the pulse rate of the person being measured.

  The reason is that if the measurement subject exercises during the measurement, the blood vessel accelerates due to the exercise, thereby disturbing the blood flow. The disturbance is superimposed on the pulse wave signal as a disturbance component. Therefore, it becomes difficult to extract a period of time fluctuation caused by pulsation from the pulse wave signal.

  Further, when the measurement subject exercises, the sensor means attached to the body part of the measurement person also accelerates, causing the sensor means to be displaced relative to the body part or temporarily. However, an event occurs in which the sensor means deviates from the body part. These events are also superimposed on the pulse wave signal as a disturbance component. Such an event also contributes to making it difficult to extract a period of time variation caused by pulsation from the pulse wave signal.

  In a pulse wave signal, it is extremely difficult to correctly distinguish between fluctuations in signal intensity caused by pulsation of blood vessels and fluctuations in signal intensity caused by disturbance components as described above. For this reason, when the method of measuring the pulse rate of the measurement subject by detecting the pulsation of the subcutaneous blood vessel of the measurement subject non-electrocardially, for example, photoelectrically, the above disturbance component is superimposed on the pulse wave signal. In order to avoid this, the person to be measured had to remain at rest during the measurement.

  This was a factor limiting the convenience of the pulse measuring device, the measurement conditions, and the diversity of the measurement environment.

  Accordingly, an object of the present invention is to provide a pulse measuring device capable of correctly measuring the pulse rate of the subject even if the subject is not in a resting state.

  Another object of the present invention is to provide a pulse measuring method capable of correctly measuring the pulse rate of the measured person even when the measured person is not at rest, and such a pulse measuring method to a computer. The object is to provide a pulse measurement program that can be executed.

In order to solve the above problems, the pulse measuring device of the present invention is
A data acquisition unit for detecting a pulse wave of the measurement subject by a pulse wave sensor and acquiring a pulse wave signal representing the pulse;
A storage unit for storing the pulse wave signal;
A frequency conversion unit for converting the pulse wave signal in the time domain stored in the storage unit into a frequency domain and obtaining a frequency spectrum of the pulse wave signal;
In the intensity axis of the frequency spectrum, a search intensity range setting unit for setting a search intensity range for searching for an intensity peak;
A peak extractor for extracting an intensity peak in a search intensity range set on the intensity axis of the frequency spectrum;
A pulse rate calculation unit that calculates the pulse rate of the person to be measured according to the frequency of the extracted intensity peak ,
The search intensity range setting unit changes the search intensity range according to the pulse rate calculated by the pulse rate calculation unit .

  In this specification, the data acquisition unit may directly acquire the pulse wave signal from the pulse wave sensor, or instead, the pulse wave signal from the pulse wave sensor is temporarily stored in a server (having a storage unit). It may be stored and acquired (indirect acquisition) from the server or the like.

  The “pulse rate” refers to the number of pulses per unit time (for example, beat per minute (BPM) which is the number of pulses per minute).

  In the pulse measuring device of the present invention, the data acquisition unit detects a pulse wave of the measurement subject by the pulse wave sensor and acquires a pulse wave signal representing the pulse. The storage unit stores the pulse wave signal. The frequency conversion unit converts the time domain pulse wave signal stored in the storage unit into the frequency domain to obtain a frequency spectrum of the pulse wave signal. The search intensity range setting unit sets a search intensity range for searching for an intensity peak on the intensity axis of the frequency spectrum. The peak extraction unit extracts an intensity peak in the search intensity range in which the frequency spectrum is set. A pulse rate calculation part calculates | requires a to-be-measured person's pulse rate according to the frequency of the extracted intensity | strength peak.

  Here, the search intensity range setting unit sets a search intensity range for searching for an intensity peak in the intensity axis of the frequency spectrum. It means to exclude from the intensity range of intensity peak extraction by the peak extraction unit. By doing so, the pulse rate of the person to be measured can be correctly calculated even if the person to be measured is not at rest.

Furthermore, in this pulse measurement device, the search intensity range setting unit changes the search intensity range according to the pulse rate calculated by the pulse rate calculation unit .

  The exercise performed by the subject affects the pulse rate and blood flow. For example, if the measurement subject exercises strongly, the pulse rate increases and the blood flow also increases. Further, if the intensity of exercise of the measurement subject decreases, the pulse rate decreases and the blood flow also decreases. The increase and decrease in blood flow appear as an increase and decrease in the spectral intensity of the frequency (pulse rate) corresponding to the fluctuation component caused by the pulsation of the blood vessel in the frequency spectrum of the pulse wave signal. Therefore, by predicting the tendency of fluctuation of the intensity peak appearing in the frequency spectrum in accordance with the pulse rate and changing the search intensity range, the frequency component derived from the pulsation of the blood vessel of the measured person in the pulse wave signal It is ensured that the intensity peak of component) is included in the search intensity range. Therefore, even if the measurement subject is not in a resting state, the pulse rate of the measurement subject can be correctly calculated.

  In the pulse measurement device of one embodiment, the frequency conversion unit, the search intensity range setting unit, the peak extraction unit, and the pulse rate calculation unit repeat the processing at a predetermined cycle, and in the first cycle When the intensity peak extracted by the peak extraction unit is a first intensity, the search intensity range setting unit calculates a value included in a ratio range predetermined for the first intensity, The search intensity range for the second period following the first period is set.

  In the pulse measurement device of this aspect, when the peak extraction unit extracts the intensity peak having the first intensity in the first period, the search intensity range for the second period following the first period is set as the first search intensity range. A value included in a predetermined ratio range is set for the intensity of. Therefore, also in the second period, it becomes more certain that the intensity peak of the frequency component (the fundamental frequency component) derived from the pulsation of the blood vessel of the measurement subject is included in the search intensity range. Therefore, even if the measurement subject is not in a resting state, the pulse rate of the measurement subject can be correctly calculated.

  In the pulse measuring device according to an embodiment, the search is performed when the pulse rate calculated by the pulse rate calculation unit in a fourth period following the third period is larger than the pulse rate measured in the third period. The intensity range setting unit sets an intensity range shifted to a higher intensity side than the search intensity range for the third period as the search intensity range for the fourth period. .

  In the pulse measuring device of this embodiment, when the pulse rate calculated in the fourth period is larger than the pulse rate measured in the third period, the pulse intensity is shifted to a higher intensity side than the search intensity range for the third period. The intensity range is set to the search intensity range for the fourth period. By doing so, even in the fourth period, it becomes more certain that the intensity peak of the frequency component (the fundamental frequency component) derived from the pulsation of the blood vessel of the measurement subject is included in the search intensity range. Therefore, even when the exercise intensity of the measurement subject changes, the pulse rate can be calculated correctly.

  In the pulse measurement device according to one embodiment, the search intensity range setting unit has the same width as the intensity width of the search intensity range for the third period, so that the search for the fourth period is performed. An intensity range is set.

  In the present specification, the “intensity range of the search intensity range” refers to the absolute value of the difference between the intensity value corresponding to the upper limit of the search intensity range and the intensity value corresponding to the lower limit. The unit of intensity here may be arbitrary.

  In this form of pulse measuring device, the processing load of the device is reduced.

  In the pulse measurement device according to one embodiment, an exercise intensity acquisition unit that further detects a movement of the measurement subject by a body motion sensor and acquires an exercise intensity signal representing the intensity of the exercise performed by the measurement subject; A search frequency range setting unit that sets a search frequency range for searching for the intensity peak on the frequency axis of the frequency spectrum, and the search frequency range setting unit adjusts the exercise intensity indicated by the exercise intensity signal. Accordingly, the search frequency range is changed, and the peak extraction unit is configured to have a common range between the search intensity range set on the intensity axis of the frequency spectrum and the search frequency range set on the frequency axis of the frequency spectrum. In the method, an intensity peak included in the search intensity range is extracted.

  In this specification, the exercise intensity acquisition unit may directly acquire the exercise intensity signal from the body motion sensor, or instead, the exercise intensity signal from the body motion sensor is transmitted to a server (having a storage unit). It may be stored once and acquired (indirect acquisition) from the server or the like.

  In the pulse measurement device of this aspect, the exercise intensity acquisition unit detects the movement of the measurement subject by the body motion sensor and acquires an exercise intensity signal representing the intensity of the exercise performed by the measurement subject. The search frequency range setting unit sets a search frequency range for searching for an intensity peak on the frequency axis of the frequency spectrum. The peak extraction unit extracts an intensity peak in a common range of the search intensity range set on the frequency axis and the search frequency range set on the frequency axis. A pulse rate calculation part calculates | requires a to-be-measured person's pulse rate according to the frequency of the extracted intensity | strength peak. The search frequency range setting unit changes the search frequency range according to the exercise intensity indicated by the exercise intensity signal. The search frequency range setting unit sets a search frequency range for searching for an intensity peak on the frequency axis of the frequency spectrum. The peak extraction unit extracts frequency components and harmonic components derived from the exercise performed by the measurement subject. It means to exclude from the frequency range of intensity peak extraction by. Therefore, even when the exercise intensity of the measurement subject changes, the pulse rate can be calculated correctly.

The pulse measuring method of this invention is
A pulse measurement method for measuring a pulse rate of a measurement subject performed by a pulse measurement device,
A data acquisition step of acquiring a pulse wave signal representing the pulse of the measurement subject by a pulse wave sensor;
A storage step of storing the pulse wave signal in a storage unit;
A frequency conversion step of converting the pulse wave signal in the time domain stored in the storage unit into a frequency domain and obtaining a frequency spectrum of the pulse wave signal;
A search intensity range setting step for setting a search intensity range for searching for an intensity peak on the intensity axis of the frequency spectrum;
A peak extraction step of extracting an intensity peak in the set search intensity range of the frequency spectrum;
Repeating the pulse rate calculating step for determining the pulse rate of the person to be measured according to the frequency of the extracted intensity peak ,
In the search intensity range setting step, the search intensity range is changed according to the pulse rate calculated in the previous pulse rate calculation step .

According to the pulse measurement method of the present invention, by predicting the tendency of fluctuation of the intensity peak appearing in the frequency spectrum according to the pulse rate and changing the search intensity range, the pulse wave signal can be changed to the pulsation of the blood vessel of the measurement subject. It is ensured that the intensity peak of the derived frequency component (its fundamental frequency component) is included in the search intensity range. Therefore, even if the measurement subject is not in a resting state, the pulse rate of the measurement subject can be correctly calculated.

The pulse measurement program of the present invention is a program for causing a computer to execute the above-described pulse measurement method .

According to the pulse measurement program of the present invention, the above-described pulse measurement method can be executed by a computer.

As is clear from the above, according to the pulse measuring device and the pulse measuring method of the present invention, the pulsation of the blood vessel of the measured person in the pulse wave signal is changed by changing the search intensity range according to the calculated pulse rate. It is ensured that the intensity peak of the frequency component (fundamental frequency component) derived from is included in the search intensity range. Therefore, even if the measurement subject is not in a resting state, the pulse rate of the measurement subject can be correctly calculated.

Moreover, according to the pulse measurement program of this invention, it is possible to cause a computer to execute the above-described pulse measurement method .

It is a typical perspective view of the external appearance of the pulse measuring device of one embodiment of this invention. It is typical sectional drawing of the pulse measuring device of one Embodiment of this invention. It is a block diagram which shows the functional structure of the said pulse measuring device. It is a figure which illustrates the circuit structure of the pulse wave sensor part for measuring the pulse wave signal of the said pulse measuring device. It is a figure which shows the operation | movement flow of the said pulse measuring device. It is a figure which shows an example of a pulse wave signal (time domain). It is a figure which shows an example of the AC component of a pulse wave signal (time domain). It is a figure which shows an example of the pulse wave signal AC component (frequency domain). (A) It is a figure which shows the example of the time change of a to-be-measured person's exercise intensity. (B) It is a figure which shows the relationship between the pulse rate calculation timing, and the time range of the pulse wave signal AC component used for pulse rate calculation in each timing. (C) It is a figure which shows the example of the time change of a pulse rate. It is a figure which shows the example of the search frequency range changed according to exercise intensity. It is a figure which shows the example of the search intensity | strength range changed according to a pulse rate. It is a block diagram which shows the functional structure of the pulse measuring device of another one Embodiment of this invention. It is a figure which shows the operation | movement flow of the pulse measuring device of another one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1A and 1B schematically show a configuration of a pulse measuring device according to an embodiment. FIG. 1A is a schematic perspective view of an appearance of a pulse measuring device according to an embodiment, and FIG. 1B is a schematic cross-sectional view of the pulse measuring device. For convenience of explanation, the side of the measurement site (not shown) is the “lower surface side” of the main body 10, and the opposite side of the measurement site is the “upper surface side” of the main body 10.

The pulse measuring device 1 includes a main body 10 and a band 20. As shown in Figure 1A, pulse measuring device 1, as in the wristwatch, the target part 3 of the band 20 the subject (e.g., wrist) by turning around a to fix the main body to the wrist of the subject be able to.

  The main body 10 of the pulse measuring device 1 is disposed in close contact with a measurement target region (not shown) of the measurement subject, and forms a contact surface with the measurement target region on the opposite side of the lower surface 13. And a top surface 11 located. The main body 10 has a constricted shape w whose size is small with respect to the surface direction along the lower surface 13 (FIG. 1B).

Body 10 of the pulse measuring device 1 includes a pulse wave sensor unit 15 as a pulse wave sensor which is arranged on the side of the lower surface 13 by measuring the pulse rate of the subject, is disposed on the side of the upper surface 11 pulse wave sensor unit 15 And a display unit 14 for displaying information related to the pulse measured by. The pulse wave sensor unit 15 disposed on the lower surface 13 side includes a light emitting element 16 such as a light emitting diode that emits measurement light (for example, infrared light or near infrared light), and light reception such as a photodiode or a phototransistor. An optical sensor including the element 17. The light emitting element 16 functions as a light emitting unit that irradiates light with a certain light emission intensity toward the measurement site. The light receiving element 17 functions as a light receiving unit that receives reflected light or transmitted light from the measurement site.

In a state where the main body 10 is disposed in close contact with the measurement site 3, measurement light (for example, infrared light or near-infrared light) emitted from the light emitting element 16 is transmitted to a blood vessel (for example, an artery) under the measurement site. ) Is reflected by red blood cells flowing through the artery, and the reflected light is received by the light receiving element 17. The amount of reflected light received by the light receiving element 17 changes according to the pulsation of the artery. Therefore, the pulse wave sensor unit 15 can detect the pulse wave information and measure the pulse rate. In FIG. 1, the pulse wave sensor unit 15 is arranged so as to be in contact with the lower surface 13, but the pulse wave sensor unit 15 is arranged inside the main body 10 and the pulse wave arranged inside the main body 10. The structure provided with the space part connected with the sensor part 15 and the lower surface 13 of the main body 10 may be sufficient. 1A and 1B includes a pulse wave sensor unit 15 including a light emitting element 16 and a light receiving element 17 disposed in the vicinity of the light emitting element 16, and Although the type of detecting the reflected light is illustrated, the pulse wave sensor unit 15 is composed of a light emitting element 16 and a light receiving element 17 arranged to face the light emitting element 16, and passes through the measurement site 3. It is also possible to use a type that detects transmitted light.

Since this pulse measuring device 1 includes the pulse wave sensor unit 15 including a photoelectric sensor as a pulse wave sensor, it is possible to accurately detect pulse wave information including the pulse with a simple configuration.

The display unit 14 is disposed on the upper surface 11 side of the main body 10. The display unit 14 includes a display screen (for example, an LCD (Liquid Crystal Display) or an EL (Electroluminescence) display). The display unit 14 displays information (for example, the pulse rate) on the measurement subject's pulse on the display screen. The display screen is controlled by a control unit 31 (CPU) (described later) that functions as a display control unit.

  The band 20 for attaching the main body 10 to the measurement site 3 of the person to be measured has a main body holding portion 21 for tightly holding the main body 10 and a surrounding portion 25 for surrounding the measurement site.

  An opening is formed in the main body holding portion 21 so as to substantially match the outer size of the constricted shape w of the main body 10, whereby the main body 10 and the band 20 are engaged with each other at the constricted shape w portion. Yes.

  A buckle member 22 refracted into a substantially rectangular shape is attached to one end of the main body holding portion 21. Through the hole 23 of the buckle member 22, the end portion 24 of the winding portion 25 is inserted outward from the measurement site 3 and folded.

  A portion of the surrounding portion 25 other than the end portion 24 is provided with a long female side fastener extending in the longitudinal direction on the outer side surface (the surface opposite to the inner side surface in contact with the measurement site 3). The male side fastener 26 attached to the end 24 is detachably engaged.

  In this way, the main body 10 is held in close contact with the measurement site 3 by the band 20.

  FIG. 2 shows a functional block configuration of the pulse measuring device 1. The main body 10 of the pulse measuring device 1 includes a control unit (CPU) 31, a storage unit 32, a display unit 14, an operation unit 34, a pulse wave sensor unit 15, and a body motion sensor unit 33. The pulse measuring device 1 may further include a communication unit (not shown). In that case, the pulse measuring device 1 can perform data communication with an external device (not shown).

  The control unit 31 includes a CPU (Central Processing Unit) and its auxiliary circuit, controls each part of the pulse measuring device 1, and performs various processes according to programs and data stored in the storage unit 32. Run. That is, the control unit (CPU) 31 processes data input from the operation unit 34, pulse wave sensor unit 15, body motion sensor unit 33, and communication unit (not shown), and stores the processed data in the storage unit 32. They are stored, displayed on the display unit 14, or output from the communication unit.

  The storage unit 32 stores a RAM (Random Access Memory) used as a work area necessary for executing a program by the control unit (CPU) 31 and a basic program to be executed by the control unit (CPU) 31. ROM (Read Only Memory). A semiconductor memory (memory card, SSD (Solid State Drive)) or the like can be used as a storage medium of an auxiliary storage device for assisting the storage area of the storage unit 32. The storage unit 32 can store, in time series, a pulse wave signal (particularly its AC component) representing the pulse of the measurement subject detected by the pulse wave sensor unit 15 for each measurement subject.

  The operation unit 34 is, for example, a power switch operated to turn on or off the power of the pulse measuring device 1 and any person to be measured for storing the measurement result for each person to be measured in the storage unit 32. Or an operation switch operated to select what kind of measurement is to be performed. The operation unit 34 can be installed on the upper surface 11 side or the side surface 12 of the main body 10.

  Thus, the pulse measuring device 1 can be configured as a single device. However, it can also be used on a network by providing a communication unit (not shown).

  A communication unit (not shown) transmits data generated by the control unit (CPU) 31 and data stored in the storage unit 32 to a server or a control unit (not shown) of the server via a wired or wireless network. ) And data stored in a storage unit (not shown) of the server. Here, in addition to a normal server, a server is, for example, a stationary terminal such as a personal computer, a mobile phone, a smartphone, a PDA (Personal Digital Assistance), a tablet (tablet), and It means a broad concept including a portable terminal such as a remote controller of an AV device such as a television and a computer built in the AV device such as a television.

  In addition, electric power is supplied to each part of the pulse measuring device 1 from a power source (not shown) according to a user operation on the power switch of the operation unit 34.

  FIG. 3 illustrates a circuit configuration of the pulse wave sensor unit 15 of the pulse measuring device 1. The pulse wave sensor unit 15 includes a pulse wave sensor controller 41 that controls the operation of the pulse wave sensor unit 15 by operating under the control of the CPU 31.

  The pulse wave sensor controller 41 controls the pulse driving circuit 42 to drive the light emitting element 16 in pulses. That is, the pulse drive circuit 42 controls the light emission state (frequency and duty) of the light emitting element 16 by switching the npn transistor in accordance with the drive pulse supplied from the pulse wave sensor controller 41.

  The pulse wave sensor controller 41 controls the light emission intensity control circuit 43 to control the light emission intensity (that is, the drive current) of the light emitting element 16. That is, the light emission intensity control circuit 43 emits light with a drive current defined by the resistance value by changing the resistance value of the variable resistor in accordance with the light emission intensity control signal from the pulse wave sensor controller 41 controlled by the CPU 31. The element 16 is driven to control the light emission intensity of the light emitting element 16. That is, as the drive current flowing through the light emitting element 16 increases, the light emission intensity (that is, the amount of emitted light) of the light emitting element 16 increases.

The light receiving element 17 outputs a photoelectric output corresponding to the intensity of the received light. The pulse wave sensor controller 41 controls the light emitting element 16 as described above, and also controls the light receiving sensitivity adjustment circuit 44 to control the light receiving sensitivity of the light receiving element 17 (that is, the photoelectric output gain). The light receiving sensitivity adjustment circuit 44 increases or decreases the resistance value of the variable resistor in accordance with the photoelectric output control signal from the pulse wave sensor controller 41 controlled by the CPU 31 to thereby output the photoelectric output from the light receiving element 17 (in FIG. 5A). The magnitude of the pulse wave DC component P _DC ) is adjusted.

Here, the photoelectric output from the light receiving element 17 is called a pulse wave DC component P _DC. Actually, the photoelectric output output from the light receiving element 17 is a pulsating flow in which an AC component is superimposed on a certain level (DC component), but the magnitude of the pulsation is extremely small compared to the magnitude of the photoelectric output. here, the photoelectric output from the light receiving element 17, also referred to as the pulse wave DC component P _DC.

The photoelectric output from the light receiving element 17 (pulse wave DC component P _DC in FIG. 5A) is bifurcated, one is input to the bandpass filter (BPF) 45, and the other is the A / D conversion circuit (for DC component). ADC) 47D.

BPF 45 has a function of taking out the AC component from the photoelectric output _{P DC} from the light receiving element 17, the amplifier 46 has the effect of amplifying the output from the BPF 45. The pass band of the BPF 45 may include a frequency band (0.5 Hz to 5 Hz) corresponding to a general human pulse rate range (30 BPM to 300 BPM). From the amplifier 46, the photoelectric output _{P DC} AC component (pulse wave AC component PS in FIG. 5A (t)) is output, the output is input to the A / D converter (ADC for AC component) 47A.

The photoelectric signal _{P DC} output from the light receiving element 17 via the A / D conversion circuit 47D, is converted from an analog signal to a digital signal, the digital signal is CPU31 of the pulse wave AC component PS (t) from the output of ADC47A Entered. The digital signal of the pulse wave AC component PS (t) is used for calculating the pulse rate of the measurement subject and determining the search intensity range, as will be described later. From the output of the ADC 47D, a photoelectric signal (pulse wave DC component P _DC ) is input to the CPU 31 and used for arithmetic processing such as a parameter for controlling the emission intensity.

  In this example, digital signals output from the ADC 47A (AC component ADC) and the ADC conversion circuit 47D (DC component ADC) are input to the CPU 31, but the ADCs 47A and 47D are incorporated in the CPU 31. There may be.

  The body motion sensor unit 33 includes an acceleration sensor 48. The acceleration sensor 48 measures the magnitude of acceleration acting on the measurement site and outputs the measurement result to the amplifier 49. The output of the amplifier 49 is input to an A / D conversion circuit (ADC) 50, and a digital signal including acceleration information is input to the CPU 31 from the ADC 50. Here, the magnitude of the acceleration acting on the acceleration sensor 48 is considered to correspond well with the intensity of the exercise performed by the measurement subject, and the output of the acceleration sensor 48 is expressed as the intensity of the exercise performed by the measurement subject. Use as an exercise intensity signal to represent.

  This pulse measuring device 1 operates as a whole according to the flow of the pulse measuring method shown in FIG.

  Schematically, the pulse measuring device 1 first calculates the pulse rate (resting pulse rate) of a measurement subject who is in a resting state at the start of measurement. Then, in the next measurement cycle, the pulse measuring device 1 determines the peak of the spectral intensity in the pulse wave signal (more specifically, the pulse wave AC component) expressed in the frequency domain based on the pulse rate at rest. The frequency range to be searched (search frequency range) and the intensity range (search intensity range) to search for the peak of the spectrum intensity in the pulse wave signal (more specifically, the pulse wave AC component) are determined, and the search intensity range And the peak of the spectrum intensity which exists in the common range of the search frequency range is extracted, and the pulse rate of the measurement subject is calculated based on the frequency of the extracted intensity peak. In the subsequent measurement cycle, the pulse measurement device 1 uses the search frequency range in the previous measurement according to the exercise intensity signal that is output from the body motion sensor unit and represents the intensity of the exercise performed by the measurement subject. The search intensity range is shifted from the search intensity range used in the previous measurement according to the calculated pulse rate and shifted from the frequency range, and the common range is reset based on the search frequency range and the search intensity range. By extracting the peak of the spectrum intensity, the pulse rate in the current measurement cycle is calculated so as to track the change in the pulse rate from the pulse rate calculated in the previous measurement cycle.

  i) First, as shown in step S1, in order to measure the pulse rate in a resting state, the CPU 31 determines whether or not the subject is resting based on the exercise intensity signal output from the body motion sensor unit 33. To determine. If the CPU 31 determines that the measurement subject is in a resting state (“YES” in step S1), the process proceeds to step S2. Otherwise, the CPU 31 repeats step S1 at a preset cycle. In step S1, the CPU 31 obtains the frequency spectrum of the pulse wave signal (pulse wave AC component PS (t)) acquired from the pulse wave sensor unit, and the measurement subject is in a resting state from the shape of the spectrum intensity distribution. It may be determined whether or not.

ii) Next, as shown in step S <b> 2, the CPU 31 acquires a resting pulse wave signal (pulse wave AC component PS (t)) representing the pulse of the measurement subject from the pulse wave sensor unit 15. Works as. More specifically, CPU 31 that operates as a data acquisition unit acquires the AC component PS (t) contained in the photoelectric signal _{P DC.} (See FIGS. 5A and 5B.)

FIG. 5A is a diagram illustrating an example of a photoelectric signal (pulse wave DC component P _DC ) output from the light receiving element 17. 5A, the horizontal axis indicates time expressed in seconds and the vertical axis represents the intensity of pulse wave DC component P _DC (in arbitrary units). As described above, the photoelectric signal (pulse wave DC component P _DC ) is a pulsating flow including a minute AC component. That is, the pulse wave DC component P _DC is caused by pulsation of the living body (that is, a direct current component) that does not vary periodically due to light absorbed and scattered by tissues and staying blood. It is output as a pulsating flow in which a component (AC component) PS (t) that periodically changes reflecting the pulse wave of blood) is superimposed. Normally, the magnitude (amplitude) of the pulse wave AC component PS (t) that varies periodically is about two orders of magnitude smaller than the magnitude of the component (DC component) at a certain level. Therefore, it is desirable to extract the pulse wave AC component PS (t) from the photoelectric signal (pulse wave DC component P _DC ) and amplify it so that it can be handled as data. In this example, the amplifier 46 includes an operational amplifier, and controls the amplification gain of the pulse wave AC component by adjusting the resistance ratio between the input resistance and the feedback resistance under the control of the CPU 31. The pulse wave AC component PS (t) output from the amplifier 46 passes through the ADC 47A and becomes a pulse wave AC component PS (t) of a digital signal and is input to the CPU 31.

  FIG. 5B illustrates the waveform of the pulse wave AC component PS (t) input to the CPU 31. In FIG. 5B, the horizontal axis represents time (seconds), and the vertical axis represents the intensity (unit is arbitrary) of the pulse wave AC component PS (t). The pulse wave AC component PS (t) periodically changes according to the pulsation of the living body (that is, the pulse wave of blood). That is, the pulse wave AC component PS (t) is a pulse wave signal representing the pulse of the measurement subject. The pulse wave AC component PS (t) is stored in time series in the storage unit 32 shown in FIG.

  iii) Next, as shown in step S3 of FIG. 4, the CPU 31 converts the pulse wave signal (pulse wave AC component PS (t)) in the time domain stored in the storage unit 32 into the frequency domain. , And operates as a frequency converter that obtains the frequency spectrum (PS (f)) of the pulse wave signal (pulse wave AC component PS (t)). More specifically, the CPU 31 that operates as a frequency conversion unit converts the resting pulse wave signal (pulse wave AC component PS (t)) stored in the storage unit 32 into the frequency domain, The frequency spectrum PS (f) of the pulse wave AC component at the time is obtained. In this example, the CPU 31 performs fast Fourier transform (FFT) on the resting pulse wave signal (pulse wave AC component PS (t)) by operating as frequency conversion. As illustrated in FIG. 7B, the CPU 31 determines a period Td (for example, a predetermined length) of the pulse wave AC component PS (t) at rest stored in the storage unit 32 in time series. The frequency spectrum PS (f) of the AC component PS (t) at rest included in 16 seconds, 8 seconds, 4 seconds, etc.) is obtained.

  FIG. 6 is a diagram illustrating an example of a resting pulse wave AC component PS (f) converted into the frequency domain. In FIG. 6, the horizontal axis represents the pulse rate (the unit is BPM (30 BPM is equivalent to 0.5 Hz)), and the vertical axis is the spectrum intensity (the unit is arbitrary). In this example, the resting AC component PS (f) converted to the frequency domain has a large peak at about 60 BPM. The harmonic components appear at about 120 BPM and about 180 BPM.

  iv) Next, as shown in step S4 of FIG. 4, the CPU 31 operates as a peak extraction unit that extracts an intensity peak in a search frequency range in which a frequency spectrum is set. At the start of measurement (when obtaining the pulse rate (resting pulse rate) of the subject in a resting state), the search frequency range is the entire frequency range (for example, 30 BPM to 300 BPM, that is, 0.5 Hz to 5 Hz). As good as In the example of FIG. 6, the CPU 31 extracts the intensity peak of the frequency spectrum PS (f) at approximately 60 BPM. The CPU 31 discards a relatively small intensity peak at approximately 120 BPM and approximately 180 BPM as a harmonic component of an intensity peak that appears at approximately 60 BPM. Next, the CPU 31 operates as a pulse rate calculation unit that obtains the pulse rate of the measurement subject at rest according to the frequency of the extracted intensity peak, whereby the frequency of the extracted intensity peak (in the case of FIG. 6). 1 Hz), the measurement subject's resting pulse rate is determined to be approximately 60 BPM.

  v) Next, as shown in step S5 of FIG. 4, the CPU 31 operates as a search frequency range setting unit that sets a search frequency range for searching for an intensity peak on the frequency axis of the frequency spectrum. Specifically, the CPU 31 that operates as the search frequency range setting unit has a ratio range (for example, a predetermined rate range) with respect to the pulse rate calculated in the previous measurement (here, the pulse rate at rest (approximately 60 BPM)). A value included in (within plus or minus 20%) is set in the search frequency range for the next measurement cycle. For example, the CPU 31 sets a range of values within plus or minus 20% with respect to the pulse rate (resting pulse rate) calculated in the previous measurement cycle as the search frequency range for the next measurement cycle. If the pulse rate calculated in the previous measurement cycle is 60 BPM as shown in FIG. 6, the range of 48 BPM to 72 BPM is set as the search frequency range for the next measurement cycle.

  vi) Next, as shown in step S6 of FIG. 4, the CPU 31 operates as a search intensity range setting unit that sets a search intensity range for searching for an intensity peak on the intensity axis of the frequency spectrum. Specifically, the CPU 31 operating as the search intensity range setting unit has a predetermined ratio with respect to the intensity peak value in the pulse rate calculated in the previous measurement (here, the pulse rate at rest (approximately 60 BPM)). An intensity peak value included in a range (for example, within plus or minus 20%) is set as the search intensity range for the next measurement cycle. For example, if the pulse rate calculated in the previous measurement cycle is 60 BPM as shown in FIG. 6, the CPU 31 has a plus or minus 20% intensity value 1 (unit is arbitrary) at 60 BPM of the frequency spectrum PS (f). A range of 0.8 to 1.2 (arbitrary unit) is set as a search intensity range for the next measurement.

  Hereinafter, the processing loop from step S7 to step S17 in FIG. 4 is a processing flow related to the pulse rate measurement for the second and subsequent times from the start of measurement. A series of processing from step S7 to step S17 is performed by one pulse rate measurement. This series of processing is performed at a predetermined measurement cycle (for example, at intervals of 5 seconds (time interval Ts in FIG. 7)) until the end of measurement. The pulse measuring device 1 sets the search frequency range to the previous search frequency as necessary based on the exercise intensity signal output from the body motion sensor unit 33 in the second and subsequent pulse rate measurements from the start of measurement. In addition to shifting from the range, the search intensity range is shifted from the search intensity range used in the previous measurement according to the calculated pulse rate, and the common range is changed based on the search frequency range and the search intensity range. The CPU 31 that operates as a peak extraction unit extracts a spectrum intensity peak that is obtained in this way and includes an intensity value in the common range of the search frequency range and the search intensity range, and the CPU 31 that operates as a pulse rate calculation unit. The pulse rate is calculated according to the frequency of the extracted peak.

  vii) As shown in step S <b> 7 of FIG. 4, the CPU 31 operates as an exercise intensity acquisition unit, and acquires from the body motion sensor unit 33 an exercise intensity signal representing the intensity of exercise performed by the measurement subject.

  viii) Next, as shown in step S8, the CPU 31 operating as the search frequency range setting unit calculates the exercise intensity of the measurement subject in the previous measurement cycle and the exercise intensity of the measurement subject in the current measurement cycle. Comparison is made based on the intensity signal, and it is determined whether the exercise intensity in the current measurement cycle has increased, has not changed, or has been reduced compared to the exercise intensity in the previous measurement cycle.

  FIG. 7A is a diagram illustrating a relationship between a time change example (three examples) of exercise intensity and a measurement cycle. The horizontal axis represents time, and the vertical axis represents the exercise intensity of the measurement subject determined based on the exercise intensity signal. The exercise intensity here may be a value at each time of acceleration output from the body motion sensor unit 33 (acceleration sensor 48). Alternatively, the exercise intensity may be a value obtained by integrating the output of the acceleration sensor 48 over a predetermined time interval, or an exercise intensity signal output from the body motion sensor unit 33 by another predetermined calculation method. It may be a value obtained by processing. For example, the walking pitch (running pitch) of the measurement subject may be obtained from the output of the body motion sensor unit 33 (acceleration sensor 48), and the pitch may be used as the exercise intensity.

  The first exercise intensity time change example WLa is an example in which the exercise intensity in the current measurement cycle is increased from the exercise intensity in the previous measurement cycle. In the first exercise intensity time change example WLa, the exercise intensity was la1 in the previous measurement cycle (time t1), whereas the exercise intensity was la2 (la2: la2> la1 in the current measurement cycle (time t2). ). In such a case, the CPU 31 determines in step S8 that the exercise intensity in the current cycle has changed so as to increase from the exercise intensity in the immediately preceding cycle (“YES” in step S8). Therefore, the process proceeds to step S9.

  The second exercise intensity time change example WLb is an example in which there is no change between the exercise intensity in the previous measurement cycle and the exercise intensity in the current measurement cycle. In the second exercise intensity time change example WLb, the exercise intensity is lb1 in the previous measurement cycle (time t1), and the exercise intensity is lb2 (lb2: lb2 = lb1) in the current measurement cycle (time t2). . In such a case, the CPU 31 determines in step S8 that the exercise intensity of the current cycle has not changed from the exercise intensity of the immediately preceding cycle ("NO" in step S8). Therefore, the process proceeds to step S10.

  The third exercise intensity time change example WLc is an example showing a case where the exercise intensity in the current measurement cycle is lower than the exercise intensity in the previous measurement cycle. In the third exercise intensity time variation example WLc, the exercise intensity was lc1 in the previous measurement cycle (time t1), whereas the exercise intensity was lc2 (lc2: lc2 <lc1) in the current measurement cycle (time t2). ). In such a case, the CPU 31 determines in step S8 that the exercise intensity of the current cycle has changed so as to decrease from the exercise intensity of the immediately preceding cycle (“YES” in step S8). Therefore, the process proceeds to step S9.

  ix) As shown in step S9 of FIG. 4, the CPU 31 operates as a search frequency range setting unit, and the exercise intensity in the current measurement cycle is larger than the exercise intensity in the previous measurement cycle (FIG. 7 (a) ), The search frequency range is shifted (shifted) to the higher frequency side (high BPM side) than the previous search frequency range.

  Conversely, if the exercise intensity in the current measurement cycle is smaller than the exercise intensity in the previous measurement cycle (such as the exercise intensity WLc in FIG. 7A), the CPU 31 searches the search frequency range for the previous search. Shift (shift) to a lower frequency side (lower BPM side) than the frequency range.

  As shown in step S10, the CPU 31 determines the search frequency when the exercise intensity in the current measurement cycle has not changed from the exercise intensity in the previous measurement cycle (like the exercise intensity WLb in FIG. 7A). The range is not changed from the previous search frequency range.

  FIG. 8 is a diagram illustrating how the search frequency range is changed (maintained) in steps S9 and S10 of FIG. The horizontal axis represents the pulse rate (BPM), and the vertical axis represents the spectrum intensity (unit is arbitrary). Of the time-domain pulse wave signal (pulse AC component PS (t)) shown in FIG. 7B, the pulse wave signal PS (t) from t = t2−Td to t = t2 is converted into the frequency domain. What is the frequency spectrum PS (f) in FIG. In the example of FIG. 8, the search intensity range is set to a range having an intensity width (PH1−PL1) from the spectrum intensity PL1 to PH1 (PL1 <PH1).

  In the example of FIG. 8, the search frequency range of the previous measurement cycle is the frequency range SR1. The frequency range SR1 is a frequency range having a frequency width (fH1−fL1) defined by the lower limit frequency fL1 and the upper limit frequency fH1, and in the previous pulse measurement, an intensity peak is extracted in this range.

  In step S9 of FIG. 4, the CPU 31 determines the search frequency range when the exercise intensity in the current measurement cycle is larger than the exercise intensity in the previous measurement cycle (such as the exercise intensity WLa in FIG. 7A). The frequency range SR2a on the higher frequency side (high BPM side) than the previous search frequency range SR1 is shifted (shifted). Thereby, the search frequency range in the current measurement cycle is a frequency range (fH2a−fL2a) defined by the lower limit frequency fL2a (fL2a = fL1 + dPb) and the upper limit frequency fH2a (fH2a = fH1 + dPt). Here, dPb = dPt may be set, and in this case, the frequency width of the current search frequency range is the same as the frequency width of the previous search frequency range. Further, the CPU 31 increases the difference between the exercise intensity in the current measurement cycle and the exercise intensity in the previous measurement cycle (the exercise intensity difference (la2-la1) in FIG. 7A) is larger in the search frequency range. The amount of shift (dPt and dPb in Fig. 8) may be increased, so that the pulse rate that will increase as the exercise load increases can be tracked more reliably.

  Conversely, if the exercise intensity in the current measurement cycle is smaller than the exercise intensity in the previous measurement cycle (such as the exercise intensity WLc in FIG. 7A), the CPU 31 searches the search frequency range for the previous search. Shift (shift) to the frequency range SR2c on the lower frequency side (low BPM side) than the frequency range SR1. As a result, the search frequency range in the current measurement cycle is a frequency range (fH2c-fL2c) defined by the lower limit frequency fL2c (fL2c = fL1-dMb) and the upper limit frequency fH2c (fH2c = fH1-dMt). . Again, dMb = dMt, and in this case, the frequency width of the current search frequency range is the same as the frequency width of the previous search frequency range. Further, the CPU 31 increases the difference between the exercise intensity in the current measurement cycle and the exercise intensity in the previous measurement cycle (the exercise intensity difference (lc1-lc2) in FIG. 7A) is larger in the search frequency range. The amount of shift (dMt and dMb in Fig. 8) may be increased, which makes it possible to more reliably track the pulse rate that will decrease as the exercise load decreases.

  In step S10 of FIG. 4, the CPU 31 searches when the exercise intensity in the current measurement cycle has not changed from the exercise intensity in the previous measurement cycle (such as the exercise intensity WLb in FIG. 7A). The frequency range is not changed from the previous search frequency range SR1.

  x) As shown in step S11 of FIG. 4, the CPU 31 operates as a data acquisition unit to store time-series data of the pulse wave signal (pulse wave AC component PS (t)) for the current measurement cycle. Obtained from the unit 32. For example, when the time series data of the pulse wave signal (pulse wave AC component PS (t)) as shown in FIG. 7B is stored in the storage unit 32, the CPU 31 measures the current measurement cycle from time t2-Td. The time-series data of the pulse wave signal (pulse wave AC component PS (t)) up to time t2 is acquired from the storage unit 32.

  xi) Next, as shown in step S12 of FIG. 4, the CPU 31 operates as a frequency conversion unit, thereby storing a time-domain pulse wave signal (pulse wave AC component) stored in the storage unit 32 and acquired by the data acquisition unit. PS (t)) is converted into the frequency domain, and the frequency spectrum (PS (f)) of the pulse wave signal (pulse wave AC component PS (t)) is obtained. For example, the CPU 31 performs fast Fourier transform (FFT) on the time-series data of the pulse wave signal (pulse wave AC component PS (t)) of the predetermined period Td acquired in step S11, as shown in FIG. The frequency spectrum PS (f) of the pulse wave signal is derived.

xii) Then, as shown in step S13 of FIG. 4, the CPU 31 operates as a peak extraction unit, so that the search frequency range (SR2a, SR2b, or SR2b) of the current measurement period set in step S9 or step S10 SR2c) and the intensity peak (maximum point) of the frequency spectrum included in the common range of step S6 or the search intensity range (PL1 to PH1) of the current measurement period set in step S15 or step S16 in the previous measurement period. To extract. Then, CPU 31, by operating as pulse rate calculating section calculates the number of pulse rate of the subject in accordance with the frequency of the extracted intensity peak.

  xiii) For example, when the measurement subject in a resting state starts exercising, the pulse rate increases and the blood flow increases, and the frequency spectrum of the pulse wave signal (pulse wave AC component PS (t)) increases due to the increase in blood flow. Among PS (f), it is expected that the spectrum intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel will increase. Similarly, when the intensity of the exercise performed by the subject further increases, the pulse rate further increases and the blood flow increases, and the increase in the blood flow causes the pulse wave signal (pulse wave AC component PS (t)) to increase. Of the frequency spectrum PS (f), it is expected that the spectrum intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel will increase. On the contrary, when the intensity of the exercise performed by the measurement subject decreases, the pulse rate decreases and the blood flow decreases, and the frequency of the pulse wave signal (pulse wave AC component PS (t)) decreases due to the decrease in blood flow. It is expected that the spectrum intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel in the spectrum PS (f) will decrease.

  Therefore, even when the intensity value of the spectrum intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel included in the frequency spectrum PS (f) varies, the intensity value is within the search intensity range. As shown in step S14 in FIG. 4, the CPU 31 functions as a search intensity range setting unit that sets a search intensity range for searching for an intensity peak on the intensity axis of the frequency spectrum. Specifically, the CPU 31 as the search intensity range setting unit compares the pulse rate of the measurement subject in the previous measurement cycle with the pulse rate of the measurement subject in the current measurement cycle, and the pulse rate in the current measurement cycle. Is increased, not changed, or decreased from the pulse rate in the previous measurement cycle.

  FIG.7 (c) is a figure which shows the relationship between the time change example (3 examples) of a pulse rate, and a measurement period. The horizontal axis represents time, and the vertical axis represents the pulse rate of the measurement subject calculated by the pulse rate calculation unit in each measurement cycle.

  The first pulse rate time change example Pa is an example showing a case where the pulse rate in the current measurement cycle has increased from the pulse rate in the previous measurement cycle. In the first pulse rate time change example Pa, the pulse rate was B1 in the previous measurement cycle (time t1), whereas the pulse rate was Ba2 (Ba2: Ba2> B1 in the current measurement cycle (time t2). ). In such a case, the CPU 31 determines in step S14 in FIG. 4 that the pulse rate of the current cycle has changed so as to increase from the pulse rate of the immediately preceding cycle (“YES” in step S14). Therefore, the process proceeds to step S15.

  The second exercise intensity time change example Pb is an example in which there is no change between the pulse rate in the previous measurement cycle and the pulse rate in the current measurement cycle. In the second pulse rate time change example Pb, the pulse rate is B1 in the previous measurement cycle (time t1), and the pulse rate is Bb2 (Bb2: Bb2 = B1) in the current measurement cycle (time t2). . In such a case, the CPU 31 determines in step S14 in FIG. 4 that the pulse rate of the current cycle has not changed from the pulse rate of the immediately preceding cycle (“NO” in step S14). Therefore, the process proceeds to step S16.

  The third exercise intensity time change example Pc is an example in which the pulse rate in the current measurement cycle is lower than the pulse rate in the previous measurement cycle. In the third pulse rate time change example Pc, the pulse rate was B1 in the previous measurement cycle (time t1), whereas the pulse rate was Bc2 (Bc2: Bc2 <B1) in the current measurement cycle (time t2). ). In such a case, the CPU 31 determines in step S14 in FIG. 4 that the pulse rate of the current cycle has changed so as to decrease from the pulse rate of the immediately preceding cycle (“YES” in step S14). Therefore, the process proceeds to step S15.

  xiv) As shown in step S15 of FIG. 4, the CPU 31 operates as a search intensity range setting unit, and the pulse rate in the current measurement cycle is larger than the pulse rate in the previous measurement cycle (FIG. 7C). ), The search intensity range is shifted (shifted) to a higher intensity side than the current search intensity range.

  Conversely, when the pulse rate in the current measurement cycle is smaller than the pulse rate in the previous measurement cycle (as in the case of the pulse rate Pc in FIG. 7C), the CPU 31 searches the search intensity range for the previous search. Shift (shift) to a lower intensity side than the intensity range.

  As shown in step S16 of FIG. 4, the CPU 31 determines that the pulse rate in the current measurement cycle has not changed from the pulse rate in the previous measurement cycle (as in the case of the pulse rate Pb in FIG. 7C). The search intensity range is not changed from the current search intensity range.

  FIG. 9 is a diagram illustrating how the search intensity range is changed (maintained) in steps S15 and S16 of FIG. The horizontal axis represents the pulse rate (BPM), and the vertical axis represents the spectrum intensity (unit is arbitrary). Of the time-domain pulse wave signal (pulse AC component PS (t)) shown in FIG. 7B, the pulse wave signal PS (t) from t = t2−Td to t = t2 is converted into the frequency domain. What is the frequency spectrum PS (f) in FIG.

  In the example of FIG. 9, the search intensity range of the current measurement period is the intensity range PR1 (PL1 to PH1 (PL1 <PH1)). The intensity range PR1 is an intensity range of an intensity width (PH1-PL1) defined by the lower limit intensity value PL1 and the upper limit intensity value PH1, and in this pulse measurement, an intensity peak is extracted in this range. To do.

  In step S15 in FIG. 4, the CPU 31 determines the search intensity range when the pulse rate in the current measurement cycle is larger than the pulse rate in the previous measurement cycle (such as the exercise intensity Pa in FIG. 7C). , Shift (shift) the intensity range PR2a (PL2a to PH2a (PL2a <PH2a)) higher than the current search intensity range PR1. Thereby, the search intensity range in the next measurement cycle becomes an intensity range of the frequency width (PH2a−PL2a) defined by the lower limit intensity value PL2a (PL2a = PL1 + dPPb) and the upper limit frequency PH2a (PH2a = PH1 + dPPt). Here, dPPb = dPPt may be set, and in this case, the intensity width of the next search intensity range is the same as the intensity width of the current search intensity range. Further, the CPU 31 increases the difference between the pulse rate in the current measurement cycle and the pulse rate in the previous measurement cycle (the difference in pulse rate (Ba2-B1) in FIG. The amount of shift (dPPt and dPPb in FIG. 9) may be increased, which makes it possible to more reliably track the peak value of the spectral intensity that will increase as the pulse rate increases.

  Conversely, when the pulse rate in the current measurement cycle is lower than the pulse rate in the previous measurement cycle (as in the case of the exercise intensity Pc in FIG. 7C), the CPU 31 searches the search intensity range for the current search. Shift to the intensity range PR2c on the lower intensity side than the intensity range PR1. Thereby, the search intensity range in the next measurement cycle is the intensity range of the intensity width (PH2c-PL2c) defined by the lower limit intensity value PL2c (PL2c = PL1-dPMb) and the upper limit intensity value PH2c (PH2c = PH1-dPMt). It becomes. Here, dPMb = dPMt may be set, and in this case, the intensity width of the next search intensity range is the same as the intensity width of the current search intensity range. In addition, the CPU 31 increases the difference between the pulse rate in the current measurement cycle and the pulse rate in the previous measurement cycle (the difference in pulse rate (B1−Bc2) in FIG. The amount of shift (dPMt and dPMb in FIG. 9) may be increased, which makes it possible to more reliably track the peak value of the spectral intensity that will decrease as the pulse rate decreases.

  In step S16 in FIG. 4, the CPU 31 searches when the pulse rate in the current measurement cycle has not changed from the pulse rate in the previous measurement cycle (like the exercise intensity Pb in FIG. 7C). The intensity range is not changed from the current search intensity range PR1.

  Therefore, in the next measurement cycle, the CPU 31 that operates as a peak extraction unit performs peak extraction for a spectrum intensity peak having a peak value included in the search intensity range set on the intensity axis of the frequency spectrum. For example, referring to FIG. 9, it is assumed that the intensity range PR2a is set as the search intensity range of the next measurement period in the current measurement period. In step S8, step S9, and step S10 of the next measurement cycle, it is assumed that the frequency range SR is set as the search frequency range. In this case, the CPU 31 operating as a peak extraction unit extracts a spectrum intensity peak having a peak value included in the common range C of the search intensity range PR2a and the search frequency range SR. In the example of FIG. 9, the CPU 31 that operates as a peak extraction unit extracts the peak p. In this case, the CPU 31 operating as the pulse rate calculation unit calculates the pulse rate as 160 BPM according to the peak P frequency of 160 BPM (= 160/60 hertz).

  xv) In step S17 of FIG. 4, the CPU 31 determines whether or not to end the pulse measurement. If it is determined to continue the pulse measurement, the CPU 31 returns to step S7 and performs processing for the next measurement cycle. .

  As described above, the pulse measurement device 1 according to the embodiment predicts the tendency of pulse fluctuation based on the intensity of the exercise performed by the measurement subject, and considers the directionality of the predicted pulse fluctuation in advance. The search frequency range is shifted to the high frequency side or the low frequency side, or the previous search frequency range is maintained as it is, and the frequency range for extracting the peak of the spectrum intensity caused by the pulse is set. In addition, the pulse measuring device 1 predicts the trend of fluctuation of the intensity value of the spectrum intensity peak derived from the pulse based on the pulse rate of the person to be measured, and considers the directionality of the predicted intensity value fluctuation, The search intensity range is shifted to the high intensity side or the low intensity side, or the current search intensity range is maintained as it is, and the intensity range for extracting the spectrum intensity peak derived from the pulse is set. Then, the pulse measuring device 1 extracts a spectrum intensity peak having an intensity value included in the common range of the search frequency range and the search intensity range set in this way from the pulse wave signal in the frequency domain. By doing so, even if the disturbance component is superimposed on the pulse wave signal due to the subject's exercise, the peak of the spectral intensity caused by the disturbance component is It is no longer mistakenly recognized as a peak (at least the frequency of misrecognition is reduced), and even when the subject is not at rest, the pulse rate of the subject can be measured correctly. Yes.

  In the above-described example, the pulse measuring device 1 predicts an increase / decrease in blood flow from fluctuations in the pulse rate, and obtains a range of intensity values for extracting a spectrum intensity peak derived from the pulse. However, the pulse measuring device 1 grasps the tendency of fluctuation in the intensity of the exercise performed by the person to be measured based on the exercise intensity signal output from the body motion sensor unit 33, and responds to the grasped tendency of the fluctuation in exercise intensity. Thus, a range of intensity values from which a spectrum intensity peak derived from the pulse should be extracted may be obtained. The reason is that when the measurement subject in a resting state starts exercising, the blood flow increases, and the increase in the blood flow causes the frequency spectrum PS (f) of the pulse wave signal (pulse wave AC component PS (t)) to increase. This is because the spectral intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel is considered to increase. Similarly, when the intensity of the exercise performed by the measurement subject further increases, the blood flow increases, and the frequency spectrum PS (f (pulse wave AC component PS (t)) of the pulse wave signal (pulse wave AC component PS (t)) increases as the blood flow increases. ), The spectral intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel is considered to increase, and conversely, when the intensity of the exercise performed by the subject decreases, The spectrum intensity of the frequency (pulse rate) corresponding to the fluctuation component derived from the pulsation of the blood vessel in the frequency spectrum PS (f) of the pulse wave signal (pulse wave AC component PS (t)) due to the decrease in blood flow. It is because it is thought that falls.

  In the above-described example, the pulse measuring device 1 sets the range of the intensity value of the spectrum intensity peak derived from the pulse from the fluctuation of the pulse rate, and the intensity of the exercise of the measurement subject detected by the body motion sensor unit 33. Accordingly, the range of the frequency from which the spectrum intensity peak derived from the pulse is to be extracted is set, and the spectrum intensity peak whose intensity value is included in the common range of both ranges is extracted.

  However, in the pulse measuring device according to another embodiment of the present invention, a tendency of increase / decrease in blood flow is predicted based on the pulse rate, and a range of intensity values for extracting a spectrum intensity peak derived from the pulse is obtained. Alternatively, a spectrum intensity peak having an intensity value included in the intensity range may be extracted, and the pulse rate may be calculated according to the frequency of the extracted spectrum intensity peak. That is, in this embodiment, the search frequency range need not be reset based on the exercise intensity signal output from the body motion sensor unit 33 (FIG. 2 and the like).

  FIG. 10 is a block diagram showing a functional configuration of a pulse measuring device according to another embodiment. In this case, the body motion sensor unit 33 (FIG. 2 and the like) included in the pulse measuring device 1 according to the previous embodiment is omitted.

  FIG. 11 is a diagram showing an operation flow of the pulse measuring device. In this case, processing related to setting of the search frequency range (processing corresponding to steps S5, S8, S9, and S10 in FIG. 4) is omitted.

  Other configurations and operations in the pulse measurement device are the same as the configurations and operations of the pulse measurement device 1 according to the embodiment, and thus detailed description thereof is omitted. Similarly, this pulse measuring device can correctly calculate the pulse rate even if the measurement subject is not in a resting state. Note that a process corresponding to the process of step S5 in FIG. 4 may be provided, and a frequency range for searching for a spectrum intensity peak may be set based on the pulse rate at rest.

  When the body motion sensor unit 33 (FIG. 2 and the like) is omitted as described above, in step S101 of FIG. 11, the CPU 31 detects the pulse wave signal (pulse wave AC component PS ( The frequency spectrum of t)) may be obtained, and it may be determined from the shape of the spectrum intensity distribution whether or not the measurement subject is in a resting state. Alternatively, in the pulse measurement device according to the present embodiment, step S101 in FIG. 11 may be omitted, and the first measurement (measurement of the pulse rate at rest in steps S102 to S106) may be performed simultaneously with the start of measurement.

  The pulse measuring device 1 in each of the above embodiments is a pulse measuring device that calculates the pulse rate of the person to be measured based on the frequency spectrum intensity distribution of the pulse wave signal acquired non-electrocardiographically. Non-electrocardiographic means, for example, a photoelectric method, but is not limited thereto. Non-electrocardiographic methods include a piezoelectric method in addition to a photoelectric method.

Pulse measuring device 1 in the above embodiment, as the pulse wave signal, is utilized to removed components varying in a cycle of the range assumed as pulse rate of the subject (30BPM~300BPM) of the photoelectric output P _DC . However, may be utilized photoelectric output P _DC as it pulse wave signal.

Moreover, you may construct | assemble as a program for making a computer perform the above-mentioned pulse measuring method .

  Further, such a program (pulse measurement program) may be recorded on a computer-readable recording medium such as a CD-ROM and distributed. By installing the pulse measurement program in a general-purpose computer, the pulse measurement method can be executed by the general-purpose computer.

  The program stored in the storage unit 32 is encoded in a memory or other non-transitory computer-readable recording medium (memory, hard disk drive, optical disk, etc.), and the above-described pulse measuring method is applied to a general-purpose computer. It may be executed. The program may be distributed through the Internet or the like.

In the above example, the CPU 31 performs the fast Fourier transform (FFT) as the conversion to the frequency domain. However, the present invention is not limited to this. As long as it can convert a photoelectric signal P _DC of the time domain to the frequency domain, it may employ other conversion method.

Further, as the CPU 31, a dedicated hardware logic circuit that executes the pulse measuring method may be used. That is, at least one of the data acquisition unit, the exercise intensity acquisition unit, the search frequency range setting unit, the peak extraction unit, and the pulse rate calculation unit may be realized by a dedicated hardware circuit.

  In the above example, when it is determined in step S1 of FIG. 4 that the measurement subject is in a resting state, the maximum intensity peak included in the frequency spectrum of the pulse wave signal is shown in step S4 of FIG. The frequency was determined as the pulse rate of the subject's resting state. However, the present invention is not limited to this. The number of peaks or valleys of the pulse wave signal (pulse wave AC component PS (t)) is counted, and the number of fluctuations per minute is calculated from the number of repetitions of the fluctuation of the pulse wave signal (pulse wave AC component PS (t)). The pulse rate in the resting state of the measurement subject may be obtained based on the obtained value.

  The above embodiments are merely examples, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Pulse measuring device 10 Main body 15 Pulse wave sensor part 16 Light emitting element 17 Light receiving element 31 CPU
32 storage unit 33 body motion sensor unit

Claims (7)

A data acquisition unit for detecting a pulse wave of the measurement subject by a pulse wave sensor and acquiring a pulse wave signal representing the pulse;
A storage unit for storing the pulse wave signal;
A frequency conversion unit for converting the pulse wave signal in the time domain stored in the storage unit into a frequency domain and obtaining a frequency spectrum of the pulse wave signal;
In the intensity axis of the frequency spectrum, a search intensity range setting unit for setting a search intensity range for searching for an intensity peak;
A peak extractor for extracting an intensity peak in a search intensity range set on the intensity axis of the frequency spectrum;
A pulse rate calculation unit that calculates the pulse rate of the person to be measured according to the frequency of the extracted intensity peak,
The pulse intensity measuring device, wherein the search intensity range setting unit changes the search intensity range according to the pulse rate calculated by the pulse rate calculating unit. In the pulse measuring device according to claim 1 ,
The frequency conversion unit, the search intensity range setting unit, the peak extraction unit, and the pulse rate calculation unit repeat processing at a predetermined cycle,
When the intensity peak extracted by the peak extraction unit in the first period is the first intensity, the search intensity range setting unit is included in a ratio range that is predetermined with respect to the first intensity. The pulse measurement device is characterized in that a value to be set is set in the search intensity range for a second period following the first period. In the pulse measuring device according to claim 1 or 2 ,
When the pulse rate calculated by the pulse rate calculation unit in the fourth cycle following the third cycle is larger than the pulse rate measured in the third cycle, the search intensity range setting unit An intensity range shifted to a higher intensity side than the search intensity range for the period is set as the search intensity range for the fourth period. In the pulse measuring device according to claim 3 ,
The search intensity range setting unit sets the search intensity range for the fourth period to have the same width as the intensity width of the search intensity range for the third period. A pulse measuring device. In the pulse measuring device according to any one of claims 1 to 4 ,
further,
An exercise intensity acquisition unit that detects the movement of the measurement subject by a body motion sensor and acquires an exercise intensity signal representing the intensity of the exercise performed by the measurement subject;
A search frequency range setting unit for setting a search frequency range for searching for the intensity peak in the frequency axis of the frequency spectrum,
The search frequency range setting unit changes the search frequency range according to the exercise intensity indicated by the exercise intensity signal,
The peak extraction unit includes an intensity peak included in the search intensity range in a common range of a search intensity range set on the intensity axis of the frequency spectrum and a search frequency range set on the frequency axis of the frequency spectrum. A pulse measuring device, characterized by extracting the pulse. A pulse measurement method for measuring a pulse rate of a measurement subject performed by a pulse measurement device,
A data acquisition step of acquiring a pulse wave signal representing the pulse of the measurement subject by a pulse wave sensor;
A storage step of storing the pulse wave signal in a storage unit;
A frequency conversion step of converting the pulse wave signal in the time domain stored in the storage unit into a frequency domain and obtaining a frequency spectrum of the pulse wave signal;
A search intensity range setting step for setting a search intensity range for searching for an intensity peak on the intensity axis of the frequency spectrum;
A peak extraction step of extracting an intensity peak in the set search intensity range of the frequency spectrum;
Repeating the pulse rate calculating step for determining the pulse rate of the person to be measured according to the frequency of the extracted intensity peak ,
In the search intensity range setting step, the search intensity range is changed according to the pulse rate calculated in the previous pulse rate calculation step . A pulse measurement program executable by a computer of the pulse measurement device,
A pulse measurement program for causing the computer to execute the pulse measurement method according to claim 6 .

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