JP2014195710A - Biological information measuring apparatus, biological information measuring method, and biological information measuring program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological information measuring apparatus which can drastically reduce power consumption.SOLUTION: A biological information measuring apparatus 1 which is attached to a user's body and measures biological information on the user has: a pulse wave measurement section 10 which measures a pulse wave signal including a signal composition equivalent to pulsation of the user; a status determination section 43 which determines whether or not the user is in a sleeping status; and a measurement control section 45 which allows the pulse wave measurement section to intermittently perform measurement operation of the pulse wave signal when the status determination section determines that the user is in the sleeping status.

Description

  The present invention relates to a biological information measuring device, and more particularly to a biological information measuring device that measures a pulsation signal derived from a heartbeat. The present invention also relates to a measurement method of the biological information and a biological information measurement program.

  The biological information measuring device is equipped with various sensors attached to a human body, and measures pulse staying, body temperature, presence / absence of body movement, and the degree thereof based on signals from the sensors. Such a biological information measuring device has been originally developed for medical use. However, in recent years, interest in health has increased in general users, and users can easily measure their own biological information by themselves. Various information measuring devices are provided.

  And for general purpose biological information measuring devices, the purpose is to manage the health condition in detail, to calculate calorie consumption due to body movement in daily life as well as during exercise, and to use it for diet etc. There is also a biological information measuring device of a type (always measuring type) that can be always attached to a human body, such as a wristwatch type, and continuously measures biological information.

  However, the continuous measurement type biological information measurement apparatus has a problem that it is difficult to reduce power consumption because it is necessary to always operate various sensors and constantly monitor signals from the sensors.

  In addition, low power consumption is also difficult for arithmetic processing for measuring available information (heart rate, calorie consumption, body temperature, etc.) by analyzing signals from sensors. In particular, in the case of measuring a heart rate based on blood flow fluctuation (pulse wave) accompanying a heartbeat, a DSP is used to remove a noise component derived from the body motion from the blood flow disturbed by the body motion. Only a signal (beat signal) derived from the heartbeat is extracted by FFT (Fast Fourier Transform) analysis. Therefore, the biological information measuring device based on the constant wearing and the constant measurement has a higher level of processing capability, and it is more difficult to reduce the power consumption.

  Note that Patent Documents 1 to 3 below describe techniques for reducing power consumption in a biological information measurement apparatus. Patent Document 4 describes a technique for reducing the power consumption of a hearing aid that is an electronic device that is not always a biological information measurement device but is always worn on the human body.

JP 7-227383 A JP 2003-70757 A JP 2009-11850 A JP-A-9-182193

  However, it has been found that the low power consumption technology in the conventional continuous measurement type biological information measuring device including the low power consumption technology described in each of the above-mentioned patent documents is not sufficient. For example, the pulsometer described in Patent Document 1 includes a pulse wave sensor and an acceleration sensor for detecting body movement, and performs FFT analysis on a signal from the pulse wave sensor including the influence of body movement to Only the signal is detected. As described above, since FFT requires high-level arithmetic processing, the processing load on the CPU and the DSP for FFT increases, and it is difficult to reduce power consumption. Therefore, paying attention to the fact that it is not necessary to detect body movement when the biological activity is reduced, such as during sleep or at rest, and when the activity is reduced, the FFT processing is suspended to reduce power consumption.

  However, even when the activity is reduced, it is necessary to keep the pulse wave sensor operating as long as the pulse signal is measured. Also, considering the situation in which exercise suddenly starts from a certain state when the activity is reduced, it is necessary to keep the acceleration sensor running to prepare for sudden changes in body movement even if the FFT processing is stopped . Therefore, power consumption cannot be dramatically reduced.

  The pulsometer described in Patent Document 2 includes a sensor that detects contact with the skin, determines whether or not it is correctly attached, and stops measurement when it is not correctly attached. . The hearing aid described in Patent Document 4 sets a time zone to be used, and pauses operation outside of that time zone. Therefore, the techniques described in Patent Documents 2 and 4 are not techniques that can be applied to regular measurement applications.

  The biological information measuring apparatus described in Patent Document 3 measures user's biological information and wirelessly communicates the measurement information to other information processing apparatuses, and aims to reduce power consumption associated with the communication. . And the time of awakening and the time of sleep are discriminate | determined based on the signal from a pulse wave sensor, and the frequency | count of communication is reduced at the time of sleep. However, advanced calculation technology is necessary for the discrimination process itself between awakening and sleep based on the pulse wave, and as long as the calculation process is continued, a large reduction in power consumption cannot be expected.

  Therefore, an object of the present invention is to provide a biological information measuring device that can significantly reduce power consumption. Other purposes will be clarified in the following description.

A main invention for achieving the above object is a biological information measuring device that is mounted on a user's body and measures the biological information of the user,
A pulse wave measurement unit for measuring a pulse wave signal including a signal component corresponding to a user's pulsation;
A state discriminating unit for discriminating whether or not the user is in a sleeping state;
When it is determined that the state determination unit is in a sleep state, a measurement control unit that intermittently performs a pulse wave signal measurement operation by the pulse wave measurement unit, and
It is characterized by having.

It is an external view when the biological information measuring device concerning the embodiment of the present invention is seen from the front. They are the external view (A) when the said biological information measuring device is seen from the back, and the external view (B) when it sees from the side. It is a structural diagram of a pulse wave sensor provided in the biological information measuring device. It is a functional block diagram of the said biological information measuring device. It is a figure which shows the pulsation signal measurement method when the said biological information measuring device exists in a rest mode. It is the schematic of the biometric information measuring method in 1st Example of this invention. It is a figure for demonstrating the point which should be considered in the said 1st Example. It is a flowchart of the process in connection with the biometric information measuring method in 1st Example of this invention.

=== Embodiments and Examples of Other Invention ===
The subject of the present invention is a pulse that can be always worn, detects a blood flow fluctuation including a noise component caused by body movement as a pulse wave, and reflects a heartbeat based on the detected signal (pulse wave signal). This is a biological information measuring device for measuring a motion signal, or a method for measuring a pulsation signal as biological information. In the technology as a comparative example of the present invention, when it is determined that the activity is reduced in order to reduce the power consumption related to the measurement of the pulsation signal when the activity such as resting or sleeping is reduced, the FFT is performed. Processing with heavy loads such as processing is suspended and the pulse wave signal is measured as a pulsation signal.

  Here, when considering the sleep state, the time in the sleep state that occupies the day may be shorter than the time in the other state, but the characteristics of the sleep state are mostly considering the disturbance of the pulse wave due to body movement. It is a state that does not have to be present, and that state continues for a long time. The present invention was created by paying attention to the feature point of the sleep state, and the embodiment of the present invention is mounted on the user's body and measures a pulsation signal as the user's biological information. The biological information measuring apparatus according to the embodiment of the present invention is a biological information measuring apparatus capable of dramatically reducing power consumption related to measurement of a pulsation signal during sleep and power consumption related to measurement of the pulsation signal. Is a measurement method that can dramatically reduce A program for causing a computer to accurately measure a pulsation signal while reducing power consumption is also an embodiment of the present invention.

  And the Example which concerns on the biometric information measuring apparatus of this invention is good also as providing the following each characteristic in addition to the characteristic with which the Example corresponding to the said main invention is provided.

While calculating the pulsation period based on the appearance time interval of the peak of the pulse wave signal measured by the pulse wave measurement unit, predicting the appearance time of the next peak of the pulse wave signal based on the pulsation period, A measurement period setting unit that sets a predetermined period before and after the forecast time as a measurement period,
When the measurement control unit determines that the state determination unit is in a sleep state, the pulse wave measurement unit is continuously operated and the measurement period is set by the measurement period setting unit. Stop the continuous operation of the measurement unit, and when the set measurement period is reached, cause the pulse wave measurement unit to measure a pulse wave signal and cause the measurement period setting unit to reset the measurement period.

  The measurement control unit causes the pulse wave measurement unit to continuously measure the pulse wave signal when the peak of the pulse wave signal is not detected in the measurement period of a predetermined number of times.

A body motion signal measuring unit for measuring a body motion signal associated with the body motion of the human body;
Based on the pulse wave signal and the body motion signal, a pulse extraction unit that removes a noise signal in the pulse wave signal and extracts a pulse signal reflecting a user's beat, and the pulse wave measurement An pulsation measuring unit that calculates a pulsation period based on an appearance time interval of a peak of a pulse wave signal measured by the unit or a pulsation signal extracted by the pulsation extraction unit;
With
The state determination unit determines the exercise state, the rest state, and the sleep state as the user state,
The measurement control unit
When in the exercise state, while operating the body motion signal measurement unit and the pulsation extraction unit, let the pulsation measurement unit calculate the pulsation cycle based on the pulsation signal,
When in the resting state, at least the operation of the pulsation extraction unit is paused, and the pulsation measurement unit is allowed to calculate the pulsation period based on the appearance time interval of the peak of the pulse wave signal,
When in the sleep state, the operation of the pulsation extraction unit and the body motion signal measurement unit is paused, and the pulsation cycle is based on the appearance time interval of the peak of the pulse wave signal in the pulsation measurement unit. Let's calculate.

The state determination unit receives a predetermined user input and determines that the state is the sleep state. Alternatively, a biological information measuring unit that measures predetermined biological information is provided,
When the state determination unit receives designation information of a sleep state start time point by a predetermined user input, the state determination unit monitors the biological information measured by the biological information measurement unit for a predetermined period including the start time point. When it is determined that the patient is in a sleep state based on the information, the pulse wave measurement unit is operated intermittently.

In addition, the embodiment of the biological information measuring method of the present invention includes a pulse wave sensor that measures a pulse wave signal that can be worn on the user's body and includes a signal component corresponding to the user's pulsation. Depending on the computer
A state determination process for determining whether or not the user is in a sleep state;
When it is determined by the state determination process that the patient is in a sleep state, a measurement control process for intermittently performing a pulse wave signal measurement operation by the pulse wave sensor;
It is characterized by performing.

The biological information measurement program is also an object of the present invention, and the embodiment according to the program measures a pulse wave signal that can be worn on the user's body and includes a signal component corresponding to the user's pulsation. Installed on a computer equipped with a pulse wave sensor,
A state determination process for determining whether or not the user is in a sleep state;
When it is determined by the state determination process that the patient is in a sleep state, a measurement control process for intermittently performing a pulse wave signal measurement operation by the pulse wave sensor;
It is characterized by executing.

=== Embodiment of the Invention ===
As a specific embodiment of the present invention, a wristwatch-type biological information measuring device (hereinafter, measuring device) is given. This measuring device converts, for example, a pulse wave when a person wearing this measuring device (hereinafter referred to as a wearer) is walking or jogging into an electrical signal (pulse wave signal) using a sensor, By analyzing the pulse wave signal, it has a function of displaying and displaying the heart rate and calorie consumption calculated based on the heart rate to the wearer. Furthermore, even when the wearer is sleeping, the pulse wave detection and pulsation signal measurement operation are continued, and the measurement results include, for example, the average heart rate during sleep and the total during wakefulness and sleep And calculate calorie consumption. The calculation result is displayed and output when, for example, a predetermined operation input is received. And the measuring apparatus of this embodiment can reduce the power consumption of a measuring apparatus as much as possible, measuring a pulsation signal correctly at the time of sleep.

<Structure>
FIG. 1 shows an external view of the measuring apparatus 1. This measuring device 1 has an appearance similar to that of a general digital wristwatch, and includes a wristband 2 for wearing on a wrist of a person. A time, an operating state of the device, and various living bodies are provided on the front surface of a case 3. A liquid crystal display (LCD) 4 for displaying information (heart rate, calorie consumption, body temperature, etc.) by letters, numbers, or icons is arranged. Various buttons 5 for operating the measuring device 1 are disposed around the case 3 and on the frame portion on the front surface of the case 3. The measuring device 1 operates using a built-in secondary battery as a power source, and a charging terminal 6 for charging the built-in secondary battery connected to an external charger is disposed on the side of the case 3. Has been.

  FIG. 2A shows an external view of the measuring device 1 when viewed from the rear surface, that is, the back surface of the case 3. FIG. 2B shows a side view of the measuring apparatus 1 in a state of being worn on the wearer's arm 100. A pulse wave sensor 10 for detecting a wearer's pulse wave and outputting a pulse wave signal is disposed on the back surface of the case 3. The pulse wave sensor 10 detects a pulse wave at the wrist 100 of the wearer in contact with the back surface of the case 3. In the present embodiment, a configuration for optically detecting a pulse wave is provided.

  FIG. 3 is an enlarged view when the internal structure of the pulse wave sensor 10 is viewed from the side surface of the case 3. A light source 12 such as an LED and a light receiving element 13 such as a phototransistor are incorporated in a hemispherical storage space having a circular bottom surface on the back side of the case 3. The inner surface of the hemisphere is a mirror surface 11, and the light receiving element 13 and the light source 12 are respectively mounted on the upper surface and the lower surface of the substrate 14 when the bottom surface side of the hemisphere is downward.

  When the light Le is emitted from the light source 12 toward the skin 101 of the wearer's wrist 100, the irradiated light Le is reflected by the subcutaneous blood vessel 102 and returns to the hemisphere as reflected light Lr. The reflected light Lr is further reflected by the hemispherical mirror surface 11 and enters the light receiving element 13 from above.

  The intensity of the reflected light Lr from the blood vessel 102 changes due to the light absorption action of hemoglobin in the blood, reflecting the change in blood flow. The pulse wave sensor 10 causes the light source 12 to blink at a predetermined cycle earlier than the pulsation, and the light receiving element 13 outputs a pulse wave signal corresponding to the received light intensity by photoelectric conversion for every lighting opportunity of the light source 12. In the present embodiment, the light source 12 is blinked at a frequency of 128 Hz.

<Functional block configuration>
FIG. 4 shows a functional block configuration of the measuring apparatus 1. The hardware configuration of the measuring device 1 is a computer specialized in functions related to timing such as time and timer, and functions for measuring biological information such as pulsation, body movement, and body temperature. The measuring apparatus 1 uses a computer body including a CPU 20, a RAM 21, and a ROM 22 as a control unit, an oscillation circuit 23 for generating a reference clock for operating the control unit, and a clock for clocking from the reference clock. A frequency dividing circuit 24 is provided. In addition, a multiplier 25, which is a DSP that performs dedicated operations related to FFT, is provided.

  As a configuration related to the user interface, a display unit 26 for displaying information on the LCD 4 according to an instruction from the CPU 20, an alarm unit 28 for outputting an alarm sound or vibration using a piezoelectric vibrator 27, and the operation buttons 5 are provided. An input unit 29 for generating operation data describing the operation state and inputting it to the CPU 20 is provided.

  Moreover, the measuring apparatus 1 is equipped with various sensors (10, 30, 31) as a structure for measuring biological information. As described above, the pulse wave sensor 10 is mainly composed of a light source 12 such as an LED and a light receiving element 13. The body motion sensor 30 is a three-axis acceleration sensor, and outputs three systems of body motion signals according to respective accelerations in the three-axis directions. For example, as shown in FIG. 1, the normal direction of the front surface of the case 3 (from the back to the front of the paper) is the Z axis, and the direction from 6 o'clock to 12 is the Y axis. The direction orthogonal to the two axes can be the X axis. In this case, the X axis substantially coincides with the direction from the elbow to the wrist with the measuring device 1 attached. For example, the temperature sensor 31 utilizes the fact that the resistance value changes according to the temperature, and outputs the voltage between the terminals of the resistor as a temperature signal. In the present embodiment, the temperature sensor 31 is disposed on the back surface of the case 3 and, like the pulse wave sensor 10, can be in contact with the wrist 100 of the wearer to measure the temperature of the contact portion. It has become.

  Furthermore, the pulse wave signal amplifying circuit 32 and the body motion signal amplifying circuit 33 for amplifying the pulse wave signal from the pulse wave sensor 10 and the body motion signal from the body motion sensor 30, respectively, and the amplifier circuits (32, 33). The pulse wave signal and body motion signal amplified through the above and the temperature signal from the temperature sensor 31 are individually sampled and digitized every predetermined sampling period, and the respective signals are converted into pulse wave signal data and body motion signal data. And an A / D conversion circuit 34 for converting the temperature data. In this embodiment, each signal is A / D converted at a sampling frequency of 16 Hz.

  The pulse waveform shaping circuit 35 and the body motion waveform shaping circuit 36 respectively use the pulse wave signal and the body motion signal amplified through the pulse wave signal amplification circuit 32 and the body motion signal amplification circuit 33 as a predetermined threshold value. Based on the comparison, binarization is performed. The CPU 20 detects the presence or absence of a pulse wave or body movement based on the input signals from these waveform shaping circuits (35, 36). The pulsation extraction unit 41, pulsation measurement unit 42, state determination unit 43, heart rate calculation unit 44, and measurement control unit 45 are functional blocks realized by the CPU 20 executing a program stored in the ROM 22 or the like. This configuration does not exist as individual hardware in this embodiment. Of course, these configurations (41 to 45) can be replaced with a DSP or the like.

  The communication unit 50 performs information processing related to data communication between an external information processing apparatus such as a personal computer and the CPU 20. The CPU 20 transfers various data to the information processing apparatus via the communication unit 50 and receives various data from the information processing apparatus. Note that the communication unit 50 and the external information processing apparatus may be directly connected via a cable conforming to a predetermined communication standard, or may be connected via an intermediate device that is also used as a charger called a cradle. There may be a form. A form in which communication is performed using a radio signal is also conceivable. In the case of cable connection, a connector for connecting to the cable may be provided on the outer surface of the case 3. In the case of wireless communication, it is only necessary that the information processing apparatus has an interface for wireless communication.

  In the present embodiment, the communication unit 50 employs a form that communicates with the information processing apparatus via a cradle. The communication unit 50 and the cradle communicate with each other by a radio signal, and the cradle and the information processing apparatus are configured to communicate with each other through a wired connection. As a result, the information processing apparatus does not require a special wireless communication interface, and the measuring apparatus 1 does not require a connector.

  Specifically, the cradle has a shape that allows the measuring device 1 to be detachably mounted, and a configuration for communicating with the communication device 50 of the measuring device 1 by a wireless signal with the measuring device in the mounted state, and an information processing device And a configuration for communicating with a protocol in accordance with a general-purpose communication standard such as USB, and interprets and mutually converts signals having different protocols transmitted and received in communication between both the measuring apparatus 1 and the information processing apparatus. Thereby, the CPU 20 can perform data communication with the information processing apparatus via the communication unit 50.

  With the above-described configuration of the measuring apparatus 1, the CPU 20 executes a predetermined program stored in the ROM 22 in accordance with operation data from the input unit 29, and the execution result, data from the A / D conversion circuit 34, etc. Is written into the RAM 21 and the written data is read out from the RAM 21. Further, the display unit 26 is controlled to display the execution result of information processing, the operation state of the measuring apparatus 1 or the time on the LCD 4, and the alarm unit 28 is controlled to output a signal by voice or vibration.

=== Operation mode ===
The main function of the measuring apparatus 1 according to the present embodiment having the above-described configuration is to constantly detect a pulse wave and constantly measure a pulsation signal. And CPU20 of measuring device 1 measures a pulsation signal with a different algorithm according to a wearer's activity state. Specifically, the measuring device 1 is different between an exercise in which the wearer exercises and the body movement becomes active, a rest such as desk work but a little body movement, and a sleep. The pulsation signal is measured based on a different algorithm in the operating state (operation mode). As described above, the measurement apparatus 1 according to the present embodiment is capable of finely managing power consumption by providing various operation modes, and achieves both low power consumption and ensuring measurement accuracy.

  However, the feature of the measuring apparatus 1 according to the present embodiment is not only that the operation is possible in various modes. And the biggest feature is in the measurement method of the pulsation signal in the operation mode (sleep mode) during sleep, and in the sleep mode, the power consumption can be saved to the limit by the measurement method. ing. In the following, first, a pulsation signal measurement operation (exercise mode) and an operation mode at rest (rest mode) for exercise are described as conventional examples of the present invention, and then beats during sleep are described. A motion signal measurement operation (sleep mode) will be described as an embodiment of the present invention.

=== Exercise mode ===
The pulse wave signal output from the pulse wave sensor 10 during exercise reflects the fluctuation of blood flow disturbed by the influence of body movement. The state determination unit 43 is in a state where it is determined that body movement is detected based on a signal from the body movement waveform shaping circuit 36, and body movement is greater than or equal to a predetermined value based on body movement data from the A / D conversion circuit If it is in the intensity of, it is determined that it is during exercise. Alternatively, a predetermined operation may be performed on the measurement device 1 before the wearer consciously starts exercise, and the state determination unit 43 may determine that it is during exercise by inputting the operation signal. In any case, the measurement control unit 45 switches to the exercise mode when the state determination unit 43 outputs information indicating the exercise.

  In the exercise mode, the pulsation extraction unit 41 removes a noise component correlated with body movement from the pulse wave signal data and extracts only the pulsation signal. Specifically, the pulsation extraction unit 41 is a digital filter that is realized by the CPU 20 executing a predetermined program. From the pulse wave signal including noise using an application filter configured by an FIR filter or the like. Extract the beat signal. Then, the pulsation measurement unit 42 specifies the pulsation frequency (or period) by performing FFT analysis on the extracted pulsation signal data using the multiplier 25. The heart rate calculation unit 44 calculates a beat per minute, that is, a heart rate based on the specified frequency and cycle. The CPU 20 stores the heart rate data in, for example, the RAM 21, displays it on the LCD 4 in accordance with the wearer's operation, and transfers it to an external information processing apparatus via the communication unit 50.

=== Resting mode ===
The waveform of the pulse wave signal at the time of rest substantially reflects the heartbeat as the waveform 110 shown in FIG. Therefore, even if the filtering process and the FFT process are suspended, if the peak Ph that appears periodically in the pulse wave signal waveform is detected, the time tp between adjacent peaks can be regarded as the pulsation period. The heart rate calculation unit 44 can calculate the heart rate from the cycle. Even at rest, if noise is generated by hitting the measuring apparatus 1 with something, a peak Pn that is not correlated with the pulse wave signal 110 is detected, which is mistaken for the pulsation peak Ph. There is a possibility of detection. Therefore, an upper limit value TH and a lower limit value TL may be set as threshold values in the pulse wave signal 110, and only the appearance interval time of the peak Ph within the set value range may be measured.

  Thus, in the resting mode, low power consumption is achieved by suspending filtering processing and FFT processing with high load and large power consumption. For example, the body movement signal amplitude based on the body movement signal data is monitored, and when the amplitude equal to or less than a predetermined value continues for a predetermined time, it is regarded as a resting mode and the resting mode is determined. You can migrate. Of course, the mode may be changed according to user input by the wearer.

  In addition, when the wearer is awake at rest, there is a high possibility that the body motion will change suddenly, so the body motion sensor 30 needs to be always operated. If necessary, the sampling period may be lengthened to save some power. If the body motion signal continues for a predetermined time or more with an amplitude of a predetermined value or more, the mode may be shifted to the exercise mode.

=== Sleep mode ===
As described above, in the rest mode, low power consumption is achieved by pausing the filtering process and the FFT process. Even in the sleep mode, unnecessary processing is paused in the same manner as at rest. However, in the sleep mode, the power consumption can be further reduced as compared with the rest mode by devising the measurement method itself of the pulsation signal. And the measuring method of the pulsation signal in this sleep mode becomes an Example of this invention. In the following, specific examples of the procedure for measuring the pulsation signal in the sleep mode will be given as examples.

=== First Embodiment ====
As a first embodiment, a basic principle of a method for measuring a pulsation signal in a sleep mode will be described. For example, if the heart rate is 60, that is, 1 Hz, the pulse wave sensor 10 blinks the light source 11 at a frequency of 128 Hz. The A / D conversion circuit 34 A / D-converts the pulse wave signal from the pulse wave sensor 10 at a sampling frequency of 16 Hz. Accordingly, of the 128 lighting operations per second, the lighting operation is useless except for the lighting opportunity for detecting the peak of the pulse wave signal. Of the 16 sampling opportunities, the sampling opportunity other than the sampling opportunity required for peak detection is wasted. Sampling operation.

  FIG. 6 shows an outline of the pulsation signal measurement method in the first embodiment. FIG. 6A is a diagram showing the relationship between the lighting opportunity 111 of the light source 12 and the sampling opportunity 112 with respect to the pulsation signal 110, and FIG. 6B is an enlarged view inside the circle 113 in FIG. In the first embodiment, the method for measuring the pulsation period is the same as in the resting mode, and the detection period of the peak Ph of the pulse wave signal is set as the pulsation period. However, in the first embodiment, the control of the pulse wave sensor 10 and the A / D conversion circuit 34 when measuring the pulsation signal is devised. As shown in FIG. 6A, a measurement period ta for executing the measurement operation itself and a measurement pause period ts for stopping the measurement operation are provided, and as shown in FIG. 6B, the light source 12 is used only in the measurement period ta. Is turned on at 128 Hz to perform sampling. In the measurement suspension period ts, the light source 12 is not turned on and sampling is not performed. That is, the pulsation signal is measured intermittently. Thereby, the power consumption by the light source 12 related to the detection of the pulse wave itself and the power consumption related to sampling can be greatly reduced. In the sleep mode, the filtering process and the FFT process are suspended, and the operations of the body motion sensor 30, the body motion signal amplification circuit 33, and the body motion waveform shaping circuit 36 are also suspended.

  Note that the alternating period between the measurement period ta and the measurement pause period ts is, for example, the pulsation period immediately before the transition to the sleep mode or the past heart rate history is stored and the lowest heart rate is set. The period may be set together. In addition, regarding the ratio ta / ts of the length of the measurement period ta and the measurement suspension period ts, a predetermined value may be stored in advance in the ROM or the like.

=== Second Embodiment ===
When the intermittent measurement operation of the pulsation signal is constantly performed from the start of the measurement as in the first embodiment, the heart rate gradually changes during the sleep for a long time, and finally shown in FIG. As described above, there is a possibility that the measurement period ta and the appearance time tp of the peak Ph in the pulse wave signal 110 are greatly shifted. In this case, the peak Ph of the pulse wave signal 110 cannot be detected, and the pulsation signal cannot be measured. The measurement period ta may be made relatively longer than the measurement suspension period ts. However, if the measurement period ta is made longer, the effect of reducing power consumption is reduced. Therefore, in the second embodiment, the peak appearance time tp of the pulse wave signal 110 is predicted, and a predetermined period before and after that prediction time is set as the measurement period ta.

FIG. 8 is a flowchart of information processing performed by the CPU 20 based on the pulsation signal measurement method in the second embodiment. When the CPU 20 shifts to the sleep mode, the intermittent measurement operation is not started immediately, and the pulse wave signal measurement process is continuously executed until the peak appearance time tp can be predicted. In this embodiment, measurement is performed until the peak of the pulse wave signal is detected twice (s1 to s5). That is, if a peak is detected twice, the time between the peaks becomes a pulsation cycle, and the next peak appearance time tp can be predicted. If the peak of the pulse wave signal is detected twice, the time interval between the two detected peaks is set as the pulsation period, and the heart rate is calculated based on the pulsation period and stored (s5 → s6 to s8). In the second embodiment, prior to the calculation of the heart rate and the storage process (s8), a parameter (the number of peaks not detected: N), which will be a forced termination condition in the sleep mode, is set to an initial value. (S6).
Furthermore, starting from the second peak detection time point, the time after the pulsation cycle has elapsed is predicted as the current time point of the next peak, and a predetermined time range including the predicted time point is set as the measurement period (s9, s10). For example, if the time in the range of the next measurement period is T and the predicted occurrence time of the next peak is T1, an appropriate time range Δt (for example, a pulsation cycle) centered on the time T1 is set. 10%) is added before and after the center thereof as the next measurement period. That is, the range of T may be T1−Δt ≦ T ≦ T1 + Δt.

  If the next measurement period is predicted, the measurement operation of the pulsation signal is stopped (s11), and the arrival of the measurement period is monitored. When the measurement period starts, the measurement operation of the pulsation signal is started (s12 → s13), and if the peak of the pulse wave signal is detected during the measurement period, the elapsed time from the previous peak detection time is calculated as a new beat. The motion period is set (s14 → s15 → s7), the heart rate is calculated and stored again, and the current peak prediction process is executed again to reset the measurement period (s8 to s10).

  However, if the prediction is wrong and the peak Ph is not detected within the set measurement period, 1 is added to the number N of undetected peaks, and the measurement period is reset based on the previous pulsation cycle ( s15 → s16, s17 → s7). If the number of undetected peaks Ph reaches the predetermined value n, the sleep mode is terminated and the rest mode is entered (s17 → s18), assuming that the heart rate has fluctuated greatly.

  As described above, in the second embodiment, by predicting the peak appearance time of the pulse wave signal, a very short period of the prediction time may be set as the pulse wave signal measurement period. The measurement suspension period can be greatly increased, and power consumption can be dramatically reduced.

=== Third embodiment ===
The first and second embodiments are characterized in the method for measuring the pulsation signal in the sleep mode. The third embodiment is characterized by an operation for shifting from another mode to a sleep mode. Below, the conditions and procedure for making it transfer to the sleep mode are shown as a 3rd Example.

<User input>
The most reliable way to enter sleep mode is by user input. That is, the user himself / herself operates the measuring apparatus 1 to switch the mode. As a user input, there are a case where an instruction is directly given to the measuring device 1 and a case where a timer reservation function which is implemented as a standard as a timekeeping function in the measuring device 1 is used to designate a time to shift to the sleep mode. . In addition, the surroundings are often darkened while sleeping, and a light receiving element may be arranged in addition to the back of the case 3 to detect that the surrounding brightness has suddenly darkened, thereby shifting to the sleep mode. . That is, in this case, the wearer performs an operation of darkening the surroundings, and the measuring apparatus 1 accepts a change in received light intensity by the light receiving element as a user input. In addition, in some cases, the location of the light receiving element may be temporarily shielded, or the room may be turned off and moved to another room. The sleep mode may be shifted after detecting that the dark state continues for a predetermined time.

  Thus, if it switches to sleep mode with a predetermined user input as an opportunity, the electric power required in order to detect a sleep state can be saved.

<User input + status monitoring>
If the wearer is in a resting state before going to bed, the transition operation to the sleep mode based on the user input can predict the peak current time point of the pulse wave signal with a certain degree of accuracy. However, the wearer himself / herself is not necessarily in a resting state or a sleeping state at the time of operation input or when the timer reservation is set.

  Therefore, for example, in the second embodiment, if the measurement period is set by predicting the current peak peak current time of the pulse wave signal before the wearer actually enters the sleep state, the set measurement period In addition, the peak of the pulse wave signal may not be detected. Therefore, if a transition to sleep mode is instructed by the user's input to the measurement device directly or indirectly by the wearer, whether or not the sleep mode is entered immediately after the transition to sleep mode. To monitor. As a result, the sleep mode can be shifted to the sleep mode after the sleep state has been reliably established, and the heart rate during sleep can be accurately measured. In addition, when designating time and making it transfer to sleep mode, what is necessary is just to make the period which monitors a wearer's state after the time or the predetermined time before and after that time.

  Moreover, what is necessary is just to monitor a body motion signal in order to determine whether it is in a sleep state. Alternatively, it can be determined using a temperature sensor. During sleep, it is known that the body temperature decreases compared to when awake, and the temperature of the periphery (such as limbs) increases due to heat dissipation immediately before sleep. It is possible to determine whether or not a sleep state has been detected by detecting an increase in temperature.

=== Other Embodiments / Examples ===
In the measurement apparatus 1 of the above embodiment, the pulse wave is detected optically. Not only this embodiment but a pulse wave can also be measured using passive elements, such as a piezoelectric element. Passive devices consume little power, even in active mode. Therefore, in a measuring apparatus using a passive element as a pulse wave sensor, power can be saved by sampling the signal from the passive element only in the measurement period in the sleep mode.

  In the said 2nd Example, an example of the transfer procedure from sleep mode to rest mode was shown. The method for ending the sleep mode is not limited to this example, and a method based on user input is conceivable as in the third embodiment. That is, if the measuring device 1 is directly operated, it can be determined that the wearer is surely awake. Alternatively, there is a method of forcibly awakening by setting an alarm alarm.

  Of course, the alarm may wake up before the alarm is activated. In some cases, the alarm does not wake up. Therefore, a process for determining whether or not the wearer is in a sleep state is performed by setting a scheduled wake-up time in advance and setting a predetermined period before and after that time as a state monitoring period. Whether or not the patient is in a sleep state can be determined by detecting a change in the body motion signal.

  Note that the form of the measuring device 1 is not limited to the wristwatch type as long as it can be always worn. On the other hand, there are general-purpose computers such as a wristwatch that can be always worn, and it is easy to mount a pulse wave sensor on such a computer. Therefore, a program that is installed in an always-mounted computer equipped with a pulse wave sensor and causes the computer to function as a biological information measuring device can be used as an embodiment of the present invention.

  The present invention can be applied to a device that outputs information related to the pulsation of a human body. For example, a pulsometer, a device that calculates calorie consumption based on a heart rate, and an electrocardiograph The present invention can be applied to a device that displays and outputs a time series change by a waveform or the like.

  DESCRIPTION OF SYMBOLS 1 Biological information measuring device, 4 Liquid crystal display, 5 Operation button, 10 Pulse wave sensor, 20 CPU, 21 RAM, 22 ROM, 23 Oscillation circuit 25, 24 Dividing circuit, 25 Multiplier, 26 Display part, 28 Alarm part , 29 input unit, 30 body motion sensor, 31 temperature sensor, 34 A / D conversion circuit, 41 pulsation extraction unit, 42 pulsation measurement unit, 43 state determination unit, 44 heart rate calculation unit, 45 measurement control unit.

Claims (8)

A biological information measuring device that is mounted on a user's body and measures the biological information of the user,
A pulse wave measurement unit for measuring a pulse wave signal including a signal component corresponding to a user's pulsation;
A state discriminating unit for discriminating whether or not the user is in a sleeping state;
When it is determined that the state determination unit is in a sleep state, a measurement control unit that intermittently performs a pulse wave signal measurement operation by the pulse wave measurement unit, and
A biological information measuring device comprising: In claim 1,
While calculating the pulsation period based on the appearance time interval of the peak of the pulse wave signal measured by the pulse wave measurement unit, predicting the appearance time of the next peak of the pulse wave signal based on the pulsation period, A measurement period setting unit that sets a predetermined period before and after the forecast time as a measurement period,
When the measurement control unit determines that the state determination unit is in a sleep state, the pulse wave measurement unit is continuously operated and the measurement period is set by the measurement period setting unit. Stop the continuous operation of the measurement unit, and when the set measurement period, the pulse wave measurement unit to measure the pulse wave signal, the measurement period setting unit to reset the measurement period,
The biological information measuring device characterized by the above-mentioned.   3. The measurement control unit according to claim 2, wherein the pulse wave measurement unit continuously measures the pulse wave signal when the peak of the pulse wave signal is not detected in the measurement period of a predetermined number of times. A biological information measuring device characterized by the above. In any one of Claims 1-3,
A body motion signal measuring unit for measuring a body motion signal associated with the body motion of the human body;
Based on the pulse wave signal and the body motion signal, a pulse extraction unit that removes a noise signal in the pulse wave signal and extracts a pulse signal reflecting a user's beat, and the pulse wave measurement An pulsation measuring unit that calculates a pulsation period based on an appearance time interval of a peak of a pulse wave signal measured by the unit or a pulsation signal extracted by the pulsation extraction unit;
With
The state determination unit determines the exercise state, the rest state, and the sleep state as the user state,
The measurement control unit
When in the exercise state, while operating the body motion signal measurement unit and the pulsation extraction unit, let the pulsation measurement unit calculate the pulsation cycle based on the pulsation signal,
When in the resting state, at least the operation of the pulsation extraction unit is paused, and the pulsation measurement unit is allowed to calculate the pulsation period based on the appearance time interval of the peak of the pulse wave signal,
When in the sleep state, the operation of the pulsation extraction unit and the body motion signal measurement unit is paused, and the pulsation cycle is based on the appearance time interval of the peak of the pulse wave signal in the pulsation measurement unit. The biological information measuring device characterized by calculating.   5. The biological information measuring apparatus according to claim 1, wherein the state determination unit receives a predetermined user input and determines that the sleep state is established. In any one of Claims 1-4,
A biological information measuring unit for measuring predetermined biological information;
When the state determination unit receives designation information of a sleep state start time point by a predetermined user input, the state determination unit monitors the biological information measured by the biological information measurement unit for a predetermined period including the start time point. When it is determined that the patient is in a sleep state based on the information, the biological information measuring device operates the pulse wave measuring unit intermittently. With a computer equipped with a pulse wave sensor that can be worn on the user's body and measures a pulse wave signal containing a signal component equivalent to the user's pulsation,
A state determination process for determining whether or not the user is in a sleep state;
When it is determined by the state determination process that the patient is in a sleep state, a measurement control process for intermittently performing a pulse wave signal measurement operation by the pulse wave sensor;
The living body information measuring method characterized by performing. Installed in a computer equipped with a pulse wave sensor that measures a pulse wave signal that can be worn on the user's body and includes a signal component corresponding to the user's pulsation.
A state determination process for determining whether or not the user is in a sleep state;
When it is determined by the state determination process that the patient is in a sleep state, a measurement control process for intermittently performing a pulse wave signal measurement operation by the pulse wave sensor;
The biological information measurement program characterized by performing this.

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