JP6436186B2 - Biological information detection device - Google Patents

Description

  The present invention relates to a biological information detection device and the like.

  2. Description of the Related Art In recent years, biological information detection devices that are worn on a user's arm or the like are widely known. As biological information detected by the biological information detecting device, for example, pulse wave information such as a pulse rate can be considered. In this case, the biological information detection device is a pulse meter in a narrow sense, and measures a user's pulse rate based on a signal from a pulse wave sensor included in the pulse meter.

  In a biological information detection device worn on an arm or the like, it is important information whether the biological information detection device is in a wearing state or a non-wearing state. For example, the pulse wave sensor includes a light emitting unit (LED, etc.) and a light receiving unit (photodiode, etc.), and the light receiving unit detects reflected light reflected by the living body or transmitted light that has passed through the living body. Consider the case. In this case, the light to be detected by the light receiving unit is the reflected light or transmitted light, and the reflected light or transmitted light can be detected if the biological information detection device is in the worn state. The relative positional relationship with the living body is indefinite, and reflected light and transmitted light cannot be detected appropriately.

  Furthermore, in a non-wearing state, there is a high possibility that the light receiving unit will detect external light such as ambient light. In this case, the pulse wave sensor outputs a signal value that has nothing to do with the user's pulse. By misidentifying a signal value unrelated to the pulse as a pulse wave signal, the calculated pulse rate does not reflect the user's pulse state, and processing using the pulse rate (for example, the health of the target user) (Advice processing for the condition) is also adversely affected.

  If the user inputs the wearing state of the biological information detection device each time, the wearing state can be detected with high accuracy. However, since such an operation is cumbersome, there is a great demand for automatically determining the wearing state of the biological information detection device from the viewpoint of user friendliness.

  For example, Patent Document 1 describes that the output voltage value of the pulse wave sensor differs between the wearing state and the non-wearing state. Therefore, it is considered that it is possible to discriminate between the wearing state and the non-wearing state by performing a comparison process between the voltage value of the pulse wave sensor and a given threshold value.

JP 2005-270544 A

  The output voltage value of the pulse wave sensor varies depending on various factors. For example, the voltage value of the pulse wave sensor is different between when the subject is outdoors on a fine day when the influence of outside light is great and when the subject is in a dark room. Alternatively, the amount of hemoglobin or melanin in the user's skin varies among individuals, but the voltage value of the pulse wave sensor changes due to the difference in the attenuation rate of LED light due to the difference in the amount. Furthermore, it is known that the voltage value of the pulse wave sensor varies depending on the pressure representing the pressure on the living body (skin) in the pulse wave sensor portion of the biological information detection device.

  Therefore, if the output voltage value of the pulse wave sensor is simply compared with the predetermined threshold value, it is not possible to deal with the fluctuation of the voltage value due to the above factors, and there is a possibility of erroneous determination of wearing or non-wearing.

  According to some aspects of the present invention, a biological information detection apparatus and the like that accurately determine a wearing state and a non-wearing state by using a change value of a DC component of a pulse wave sensor signal in a given period are provided. be able to.

  One aspect of the present invention includes a pulse wave detection unit that outputs a pulse wave sensor signal, and a processing unit that processes the pulse wave sensor, wherein the processing unit is configured to output the pulse wave sensor signal in a given period. The present invention relates to a biological information detection apparatus that performs a removal detection process of the biological information detection apparatus based on a change value of the DC component.

  In one aspect of the present invention, the change value of the DC component of the pulse wave sensor signal is used for detection of removal of the biological information detection device. Therefore, even if various fluctuation factors are considered in the signal value of the DC component, the influence of the fluctuation factor can be suppressed by the process of obtaining the change value, and the removal detection process can be performed with high accuracy.

  In one embodiment of the present invention, the processing unit includes the change value of the DC component of the pulse wave sensor signal in the given period, and the given period and more than the given period. The removal detection process may be performed based on a second change value representing a change in the DC component of the pulse wave sensor signal in the second period, which is a long period.

  As a result, even when the change value of the DC component in a relatively short period shows a tendency similar to that at the time of removal (for example, when an impact is applied to the biological information detection device), By using the change value of the DC component, it is possible to suppress the possibility of misrecognizing that the removal has been performed.

  In the aspect of the invention, the processing unit may be configured such that the change value of the DC component of the pulse wave sensor signal in the given period exceeds a given threshold value and the change in the second period. If the second change value exceeds the second threshold value, it may be determined that the biological information detection device has been removed.

  Accordingly, it is possible to perform a removal detection process based on a comparison process between a change value of each DC component and a threshold value.

  The aspect of the invention may further include a body motion sensor that outputs a body motion signal, wherein the processing unit is configured such that the change value of the DC component of the pulse wave sensor signal in the given period is a given value. When the body motion signal in a period corresponding to the given period is less than or equal to a given body movement threshold, it may be determined that the biological information detection device has been removed.

  Thereby, even when the change value of the DC component in a relatively short period shows a tendency similar to that at the time of removal (for example, when an impact is applied to the biological information detection device), the body motion signal is used. Thus, it is possible to suppress the possibility of misidentifying that the removal has been performed.

  In the aspect of the invention, the processing unit may initialize parameters in the pulse wave determination process based on the pulse wave sensor signal when the removal of the biological information detection device is detected by the removal detection process. Processing may be performed.

  Thereby, when the removal is detected (when the biological information detection device is in a non-wearing state), it is possible to initialize the parameter for the pulse wave determination process.

  In one embodiment of the present invention, the processing unit sets a window corresponding to a given frequency range including a frequency determined as a pulse frequency in the determination processing of the pulse wave in the past, and is included in the window. Is performed as the determination processing of the pulse wave based on the pulse wave sensor signal, and the processing unit is configured to remove the biological information detection device by the removal detection processing. If detected, the initialization processing of the window may be performed.

  This makes it possible to initialize a window that is a parameter for pulse wave determination processing when removal is detected.

  In the aspect of the invention, the processing unit may apply the filter coefficient of the adaptive enhancer applied to the pulse wave sensor signal when the removal of the biological information detection device is detected by the removal detection process. The initialization process may be performed.

  This makes it possible to initialize the filter coefficients of the adaptive enhancer when removal is detected.

  In the aspect of the invention, the processing unit may perform the i-th DC component value at the i-th (i is a positive integer) sampling timing of the pulse wave sensor signal, and the j-th pulse wave sensor signal. A difference value from the j-th DC component value at a sampling timing (j is an integer satisfying j> i) is obtained as the change value of the DC component, and based on the obtained change value of the DC component, The removal detection process may be performed.

  This makes it possible to use a difference value between DC component values at two different sampling timings as a change value of the DC component in a given period.

  In the aspect of the invention, the processing unit may detect the biological information detection device when the change value of the DC component of the pulse wave sensor signal in the given period exceeds a given threshold value. It may be determined that has been removed.

  Accordingly, it is possible to perform the removal determination process based on the comparison process between the change value of the DC component and the threshold value.

  Moreover, in one aspect of the present invention, the processing unit includes the DC component of the pulse wave sensor signal in a third period that is a period after the removal of the biological information detection device is detected by the removal detection process. On the basis of the third change value representing the change, the reattachment detection process of the biological information detection device may be performed.

  This makes it possible to determine not only removal but also remounting based on the change value of the DC component.

The example of the mounting state of the biological information detection apparatus which concerns on this embodiment. An example of the configuration of a pulse wave sensor. The structural example of the biometric information detection apparatus which concerns on this embodiment. An example of a waveform of a pulse wave sensor signal when removal is performed. FIGS. 5A and 5B are diagrams for explaining a change value of a DC component of a pulse wave sensor signal in a given period. FIGS. 6A and 6B are diagrams for explaining the difference in the waveform of the DC component due to removal and impact. FIGS. 7A and 7B are waveform examples of the pulse wave sensor signal when an impact is applied. 8A and 8B show examples of waveforms of acceleration detection values when an impact is applied. FIGS. 9A and 9B are waveform examples of differential values of acceleration detection values when an impact is applied. FIG. 10A and FIG. 10B are waveform examples of the pulse wave sensor signal when attachment / detachment is performed. 11A and 11B show examples of waveforms of acceleration detection values when attachment / detachment is performed. FIGS. 12A and 12B are waveform examples of differential values of acceleration detection values when attachment / detachment is performed. FIGS. 13A and 13B show examples of the autocorrelation function of the AC component in the wearing state and the non-wearing state. The example of the state and event set by this embodiment. Example of state chart. The flowchart explaining the basic processing of this embodiment. 7 is a flowchart for explaining event occurrence determination processing. The flowchart explaining an event generation accompanying process. The flowchart explaining a state accompanying process. FIG. 20A shows a specific example of event occurrence associated processing, and FIG. 20B shows a specific example of state associated processing. 21A and 21B are explanatory diagrams of parameters of the pulse wave information calculation process. 22A to 22C are explanatory diagrams of the evaluation results of the method of the present embodiment.

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

1. First, the method of this embodiment will be described. As shown in FIG. 1, a biological information detection device worn on an arm or the like is widely used. The biological information detected by the biological information detection device may be, for example, pulse wave information such as a pulse rate, or information indicating an activity amount such as the number of steps. Pulse wave information can be obtained by using a pulse wave sensor, and information such as the number of steps can be obtained by using an acceleration sensor or the like.

  In the biological information detection apparatus as shown in FIG. 1, it is assumed that the biological information detection apparatus is appropriately worn on the user's arm or the like. For example, when the pulse wave sensor has a configuration including an LED and a PD (photodiode), the pulse wave sensor detects the reflected light obtained by reflecting the irradiation light from the LED with the living body by the PD, thereby detecting the pulse wave sensor signal. To get. In that case, it is considered that the irradiation light is appropriately irradiated on the living body, that the reflected light from the living body is detected by the PD with sufficient intensity, and that detection of light other than the reflected light is suppressed in the PD. For example, as shown in FIG. 2, for example, the pulse wave sensor needs to be in a positional relationship such that it closely contacts the living body.

  In the case of a clock-type biological information detecting device as shown in FIG. 1, such a positional relationship is obtained by providing a pulse wave sensor on the back side (side contacting the user's arm) of the dial portion, This is realized by appropriately fixing the detection device itself to the user's arm. In other words, it is a condition required for the calculation of pulse wave information using a pulse wave sensor that the biological information detection device is appropriately mounted.

  In addition, it is known that an appropriate pressure needs to be applied in the detection of an appropriate pulse wave sensor signal by the pulse wave sensor. The pressing here is the pressure on the living body in the pulse wave sensor as shown in FIG. In other words, by placing the biological information detection device in an appropriate wearing state, it is possible to apply an appropriate pressure by a holding mechanism such as a band, and the wearing state of the biological information detection device is also important for obtaining a pulse wave signal. It can be said that it is a thing.

  In other words, if the biological information is detected while the biological information detection device is not attached, an inappropriate result will be obtained. In the case of a pulse wave sensor, the PD detects external light that is assumed to be very strong compared to reflected light from a living body. In this case, even if the pulse wave information such as the pulse rate is obtained using the pulse wave sensor signal, it does not reflect the actual pulse rate of the user. Therefore, when processing such as generation of health advice for the user is performed using the obtained pulse rate or the like, there is a risk that inappropriate processing may be performed. Similar problems also occur in processing using signals other than pulse wave sensor signals. For example, if the number of steps is detected based on the sensor information of the acceleration sensor, the processing is performed based on the acceleration detection value resulting from walking, but when the arm is worn and not worn (for example, in a bag) In other words, the influence of the acceleration detection value due to walking should be different in the case where the band portion is held by the hand), and the same processing cannot be performed.

  That is, it is very important information whether the biological information detection device is in the mounted state or not. However, if the user inputs that information every time the biological information detection device is attached or detached, the operation becomes complicated, which is not preferable. Therefore, it is required to automatically discriminate between wearing and not wearing.

  On the other hand, Patent Document 1 describes that the voltage value of the pulse wave sensor differs between the wearing state and the non-wearing state. Therefore, it is considered possible to determine the wearing state and the non-wearing state based on this voltage value.

  However, the pulse wave sensor signal (the output voltage value of the pulse wave sensor) varies depending on various factors. For example, the magnitude of the pulse wave sensor signal is different because the amount of external light detected by the PD differs between when the subject is outdoors on a sunny day where the influence of outside light is large and when the subject is in a dark room. For example, in the non-wearing state, there is a high possibility that external light will be detected in the PD, so the pulse wave sensor signal changes greatly according to the external light condition. Even in the mounted state, since it is difficult to completely block the inflow of external light, the signal value may vary due to external light.

  It is also known that the attenuation rate of LED light varies depending on the hemoglobin and melanin of the skin. The amount of hemoglobin or melanin varies with different users, and even the same user can change due to fluctuations in physical condition or the like. That is, the pulse wave sensor signal in the wearing state fluctuates due to individual differences among users or physical condition fluctuations of the same user.

  Furthermore, it is known that the pulse wave sensor signal also fluctuates by pressing. Since the appropriate pressure is also affected by the internal pressure, which is the pressure inside the blood vessel, there are individual differences for each user and differences for the same user. Further, it is not guaranteed that each user applies the same pressing every time, that is, the mounting is performed under the same condition of a holding mechanism such as a band each time. In other words, the pulse wave sensor signal in the wearing state also varies depending on the pressure.

  As described above, since the pulse wave sensor signals in the wearing state and the non-wearing state change, it is difficult to set a threshold value that can clearly distinguish the wearing state and the non-wearing state. In other words, even if the threshold value is simply determined using the output voltage value of the pulse wave sensor, it is difficult to accurately determine whether or not the device is mounted.

  Therefore, the present applicant proposes a method for determining whether or not wearing is performed based on the change value of the DC component of the pulse wave sensor signal. As described above, since the value of the DC component itself varies depending on various factors, it is difficult to set an appropriate threshold value. However, it is possible to accurately determine attachment / detachment by using the change value of the DC component. . For example, a difference value between the maximum value and the minimum value in a given period may be obtained as the change value of the DC component. Since the fluctuation of the pulse wave sensor signal due to the above factors affects both the maximum value and the minimum value, the influence can be canceled (suppressed in a broad sense) by taking the difference value.

  As shown in FIG. 3, the biological information detection apparatus according to the present embodiment includes a pulse wave detection unit 10 that outputs a pulse wave sensor signal and a processing unit 100 that processes the pulse wave sensor signal. Based on the change value of the DC component of the pulse wave sensor signal in a given period, the biological information detection device removal detection process is performed.

  Thereby, as described above, it is possible to suppress the influence of fluctuations on the pulse wave sensor signal due to various factors, and to accurately determine the wearing state and the non-wearing state of the biological information detection device.

  Further, even if the biological information detection device is in a mounted state, if a strong impact is applied to the biological information detection device, there is a risk of erroneous determination that the biological information detection device is in a non-mounted state despite being in the mounted state. . This is because even if the biological information detection device is not removed from the arm, the pulse wave sensor may be momentarily separated from the skin if an excessive impact is applied in the vicinity of the wearing site unintentionally. In this case as well, since the pulse wave sensor signal (voltage value) changes in characteristics similar to the transition from the wearing state to the non-wearing state, the pulse meter is actually worn on the arm. There is a possibility of false detection as if it was removed from the arm.

  In view of this, the present embodiment also proposes a method for appropriately identifying the rise of the pulse wave sensor due to impact and the non-wearing state. For this, a change value (second change value) of the DC component of the pulse wave sensor signal in a second period longer than a given period targeted by simple attachment / detachment detection processing may be used. A body motion signal from a body motion sensor such as a sensor may be used. Details of each will be described later.

  Hereinafter, after describing a system configuration example of the biological information detection apparatus according to the present embodiment, a specific process of the above-described attachment / detachment detection method will be described. Furthermore, description will be given of setting of events used for states and state transitions, state transition diagrams, and the like when the processing of the present embodiment is realized as a state machine.

2. System Configuration Example FIG. 3 shows a system configuration example of the biological information detection apparatus according to this embodiment. As illustrated in FIG. 3, the biological information detection apparatus includes a pulse wave detection unit 10, a body motion detection unit 20, a processing unit 100, a display unit 200, a storage unit 300, and a communication unit 400. However, the biological information detection device and each part of the biological information detection device are not limited to the configuration in FIG. 3, and various modifications such as omitting or changing some of these components or adding other components. Implementation is possible.

  The pulse wave detection unit 10 outputs a signal based on sensor information (pulse wave sensor signal) of the pulse wave sensor. The pulse wave detection unit 10 can include, for example, a pulse wave sensor 11 and an A / D conversion unit 16.

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

  FIG. 2 is an enlarged schematic view of a part including the pulse wave sensor 11 in the biological information detection apparatus. As shown in FIG. 2, the pulse wave sensor 11 includes an LED 12 that irradiates light, a photodiode (PD) 13 that receives reflected light generated when the irradiated light is reflected by the living body, and contact with the living body. And a convex portion 14 serving as a portion. The pulse wave sensor 11 according to the present embodiment has a convex portion 14 shown in FIG. 2 and efficiently applies pressure (pressing) to a living body. Here, it is known that when detecting pulse wave information, it is possible to improve the detection accuracy by adjusting the pressure representing the pressure on the living body in the vicinity of the pulse wave sensor. Although the convex part 14 of FIG. 2 is a structure which considered press adjustment, since the method regarding the said press adjustment differs from the main point of the method of this embodiment, detailed description is abbreviate | omitted.

  The A / D converter 16 performs A / D conversion processing on the pulse wave sensor signal and outputs a digital signal.

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

  The processing unit 100 performs various processes based on the pulse wave sensor signal and the body motion signal. The processing unit 100 may include an attachment / detachment detection unit 110 and a pulse wave information calculation unit 120.

  The attachment / detachment detection unit 110 performs detection processing related to attachment / detachment of the biological information detection device based on the pulse wave sensor signal from the pulse wave detection unit 10. As shown in FIG. 3, the attachment / detachment detection unit 110 may use the body motion signal from the body motion detection unit 20 together. Specifically, the attachment / detachment detection unit 110 determines whether the device is in the attached state or the non-attached state, and performs processing in consideration of an intermediate state that is an intermediate state between the attached state and the non-attached state as described later. Also good. Details of processing of the attachment / detachment detection unit 110 will be described later.

  In addition, the attachment / detachment detection unit 110 is connected to the display unit 200, the storage unit 300, and the communication unit 400, and issues instructions regarding display, storage, and communication based on the result of the attachment / detachment detection process.

  The pulse wave information calculation unit 120 performs calculation processing of pulse wave information such as the pulse rate based on the pulse wave sensor signal. It is known that the AC component of the pulse wave sensor signal is a signal having periodicity according to the user's pulse cycle. Therefore, the pulse wave information calculation unit 120 may perform signal processing such as FFT on the AC component of the pulse wave sensor signal and perform processing for obtaining the peak frequency as the pulse frequency. Alternatively, a widely used pulse rate may be obtained by multiplying the obtained pulse frequency by 60 times.

  However, the processing in the pulse wave information calculation unit 120 is not limited to this, and various modifications can be made. For example, the frequency of the AC component of the pulse wave sensor signal may be obtained from the rise and fall of the signal on the time axis without performing conversion to the frequency axis. Moreover, since it is known that the pulse wave sensor signal includes body movement noise due to the body movement of the user, the body movement signal may be used to perform processing for reducing the body movement noise. In addition, various methods are known for calculating the pulse wave information based on the pulse wave sensor signal and the body motion signal, and in the present embodiment, they can be widely applied, and thus detailed description thereof is omitted.

  The pulse wave information calculation unit 120 outputs pulse wave information that is a calculation result to the display unit 200, the storage unit 300, and the communication unit 400.

  The display unit 200 is for displaying various display screens used for presenting the calculated pulse wave information and the like, and can be realized by, for example, a liquid crystal display or an organic EL display.

  The storage unit 300 serves as a work area for the processing unit 100 and the like, and its function can be realized by a memory such as a RAM, an HDD (hard disk drive), or the like. The storage unit 300 stores the pulse wave information calculated by the pulse wave information calculation unit 120.

  The communication unit 400 is connected to other devices via a network and communicates various information. The communication unit 400 transmits the pulse wave information calculated by the pulse wave information calculation unit 120 to another electronic device. The network here can be realized by a WAN (Wide Area Network), a LAN (Local Area Network), or the like, regardless of whether it is wired or wireless.

  An example of wearing the biological information detection apparatus of this embodiment is shown in FIG. FIG. 1 shows an example in which the biological information detection apparatus is a wristwatch type device. The base unit 500 including the pulse wave sensor 11 and the display unit 200 is attached to the left wrist of the subject (user) by a holding mechanism 600 (for example, a band).

3. Specific method of attachment / detachment detection Next, a specific method of attachment / detachment detection will be described. First, a basic method using the change value of the DC component of the pulse wave sensor signal will be described, and then a determination method from the case where an impact is applied to the biological information detection device will be described.

3.1 Basic Method Using DC Component Change Values FIG. 4 shows changes in the pulse wave sensor signal when the wearing state is changed to the non-wearing state. Here, it is assumed that the stronger the light detected by the PD 13 of the pulse wave sensor 11, the smaller the output voltage value of the pulse wave sensor signal. However, the relationship between the detected light amount and the output voltage value changes depending on the configuration of the pulse wave sensor 11, and the output voltage value may increase as the detected light amount increases.

  In FIG. 4, the biological information detection device is removed when the elapsed time is about 62 seconds. As can be seen from FIG. 4, the AC component (pulse AC) of the pulse wave sensor signal becomes a signal having periodicity corresponding to the pulse until about 56 seconds in the wearing state, and then the signal waveform is disturbed by the removal operation, and the removal is performed. Since the signal does not correspond to the pulse after the completion of, the waveform has no periodicity.

  On the other hand, the DC component (pulse DC) of the pulse wave sensor signal has a substantially constant value in a stable wearing state, and has a substantially constant value different from the wearing state in a stable non-wearing state after completion of removal. The value in the non-wearing state is a smaller value than the value in the wearing state. However, as described above, since the value in the wearing state and the value in the non-wearing state vary depending on various factors, it is difficult to accurately detect the attachment / detachment in the comparison process between each value and the threshold value. .

  Therefore, in the present embodiment, as indicated by Δ pulse DC in FIG. 4, the change value of the DC component of the pulse wave sensor signal is used. As can be seen from FIG. 4, the change value of the DC component is a value close to 0 in each of the wearing state and the non-wearing state, but the absolute value at the timing of switching from the wearing state to the non-wearing state (removal timing). Take a large value. The value in the wearing state and the value in the non-wearing state are subject to various factor variations, but the influence of the various factors is canceled on the change value of the DC component that is the difference value. The Therefore, by using the change value of the DC component, the attachment / detachment detection can be performed with high accuracy regardless of the external light condition, the difference in the hemoglobin of the user, or the fluctuation of the pressing state.

  Here, the DC component change value ΔDC1 is compared with the given threshold value Th1, and it is determined that the removal has been performed when the DC component change value is larger than the given threshold value (ΔDC1> Th1). . In FIG. 4, since ΔDC1> Th1 in the mounted state, it is determined that the mounted state has changed to the non-mounted state, that is, removal has been performed. However, in the case of a change from the non-wearing state to the wearing state (that is, remounting), the sign of the change value of the DC component is different, but the change value of the DC component should take a large value as well. Therefore, in the non-wearing state, whether or not ΔDC1> Th1 may be used for the determination of the remounting detection.

  Here, it is assumed that the change in the signal value of the DC component in the removal is performed in a relatively short period. The pulse wave sensor 11 in the mounted state is in close contact with the living body as shown in FIG. 2, and the pulse wave sensor 11 floats on the skin when removed, as shown in the vicinity of 62 seconds in FIG. A change in the DC component occurs. Then, as in the case of impact detection to be described later, a significant change appears in the DC component even if the biological information detection device floats slightly. In other words, the DC component changes greatly during the period from when the biological information detection apparatus is in contact with the skin until it floats, and it is unlikely that a long time (for example, on the order of several seconds) is required to lift the device.

  Therefore, in the present embodiment, the change value ΔDC1 of the DC component is obtained based on the DC component in a given period T1 that is somewhat short. Here, the period T1 may be a period corresponding to one period of the sampling period of the pulse wave sensor 11, for example. If the sampling frequency of the pulse wave sensor 11 is 16 Hz, the sampling period and the given period are 1/16 seconds. In this case, as shown in FIG. 5A, the difference value of the DC component of the pulse wave sensor signals that are temporally adjacent to each other becomes the change value of the DC component.

  However, the given period T1 is not limited to this, and periods corresponding to a plurality of sampling periods may be set. For example, FIG. 5B shows a case where a period of three cycles is T1. In this case, various methods for obtaining the change value of the DC component are conceivable. For example, as shown in FIG. 5B, if the difference value between the maximum value and the minimum value of the signal value of the DC component included in T1 is obtained. Good.

3.2 Impact Detection Processing As described above, the removal of the biological information detection device is detected by the comparison processing between the change value ΔDC1 of the DC component of the pulse wave sensor signal in the given period T1 and the given threshold value Th1. it can. However, when a strong impact is applied to the biological information detection apparatus, the biological information detection apparatus and the pulse wave sensor 11 provided in the biological information detection apparatus may float with respect to the living body (skin). In that case, the PD 13 of the pulse wave sensor 11 cannot appropriately detect the reflected light reflected by the living body of the irradiation light from the LED 12, and there is a possibility that external light may enter from the gap between the skin and the biological information detecting device. . Therefore, during the period when the pulse wave sensor 11 is floating, the pulse wave sensor signal exhibits the same characteristics as the non-wearing state.

  Specifically, when the removal is performed, the DC component of the pulse wave sensor signal changes as shown in FIG. 6A (decreases in the example of FIG. 6A). When added, the DC component value temporarily decreases as shown in FIG.

  Therefore, the change value ΔDC1 of the DC component in a given period T1 becomes a large value as shown in FIG. 6B even in the case of impact detection that is not actually removed. Th1 is exceeded. In such a case, it is not preferable because an erroneous determination that the device has been removed and shifted to the non-wearing state even though the wearing state is continued.

  A specific example will be described with reference to the drawings. FIG. 7A and FIG. 7B show changes in the pulse wave sensor signal when an impact is applied. In FIG. 7A and FIG. 7B, an impact is given to the biological information detection apparatus every 30 seconds from the time when 60 seconds have passed. As shown in FIG. 7A, at the timing when an impact is applied, a large value change is observed in both the AC component and the DC component of the pulse wave sensor signal. Therefore, the change value ΔDC1 of the DC component also takes a value that is somewhat large at the timing when the impact is applied, as shown in FIG. In FIG. 7B, the difference value of the DC component at the adjacent timing is the change value of the DC component, which corresponds to the case where the given period T1 is one sampling period.

  10A and 10B show changes in the pulse wave sensor signal when being removed and remounted. In FIGS. 10A and 10B, the biological information detection device is removed from the arm when 60 seconds, 120 seconds, and 187 seconds have elapsed, and the biological information detection device is armed when 90 seconds, 150 seconds, and 206 seconds have elapsed. It is attached to. As shown in FIG. 10A, a large value change is observed in both the AC component and DC component of the pulse wave sensor signal at the timing corresponding to both removal and mounting. Therefore, as shown in FIG. 10B, the change value ΔDC1 of the DC component also becomes a large value at the corresponding timing. Also, as shown in FIG. 10B, ΔDC1 takes a very large value when removed, but takes a relatively small value when reattached.

  When comparing FIG. 7B and FIG. 10B, when both removal and impact determination, and reattachment and impact determination are attempted, the difference in the value of ΔDC1 is not large (specifically, Since the value of ΔDC1 in the case of remounting and impact is close), it is difficult to discriminate only from ΔDC1. For example, when the threshold value Th1 for detecting both removal and remounting is set, there is a high possibility that the value of ΔDC1 when an impact is applied also exceeds Th1.

  Therefore, in this embodiment, the determination of impact detection may be performed in accordance with the determination using ΔDC1 at T1. Even when ΔDC1 exceeds Th1, if an impact is detected, it is determined that the change value of the DC component is due to the impact and that the removal has not been performed. Further, when ΔDC1 exceeds Th1 and no impact is detected, it may be determined that the removal has been performed.

  In the present embodiment, the collision determination may be performed using the change value ΔDC2 of the DC component in the second period T2 different from T1, or the collision determination is performed using the body motion signal from the body motion sensor. Or both of them may be used in combination. Hereinafter, each method will be described.

  First, a method using ΔDC2 at T2 will be described. As described above, the change value ΔDC1 of the DC component at T1 increases to some extent both in the case of removal and in the case of an impact, and it is difficult to accurately discriminate. However, the removal and the impact can be discriminated if a stable state where the signal value of the DC component is stable before and after T1 is seen.

  As shown in FIG. 4 and FIG. 6, it is understood that the signal value of the DC component is in a stable state in which a large fluctuation does not occur in a situation where the wearing state is continued or a non-wearing state is continued. Yes. Therefore, when the detachment is actually performed and the transition is made from the mounted state to the non-mounted state, as shown in FIG. 6A, before the DC component changes at T1 (specifically, the DC component due to the detaching operation). Before the effect on the device occurs), the value corresponding to the wearing state can be stably obtained, and after the change of the DC component at T1 (specifically, after the influence of the removal operation is sufficiently suppressed), the wearing state is not A value corresponding to is stably obtained. Accordingly, when the change value ΔDC2 of the DC component at T2 that includes T1 and is longer than T1 is obtained, ΔDC2 becomes a somewhat large value when there is a removal. Here, for example, as described above, T2 is a period of time including both the timing before the influence of the DC component on the signal value due to the removal operation and the timing after the influence is sufficiently reduced.

  On the other hand, when an impact is applied without being removed, both before and after the change of the DC component at T1 correspond to the mounted state. Therefore, as shown in FIG. 6B, when the change value ΔDC2 of the DC component in the period T2 is obtained, ΔDC2 becomes a value close to zero.

  As described above, it is possible to perform the collision determination based on the comparison process between ΔDC2 at T2 and the given threshold value Th2. Specifically, if ΔDC2 is larger than Th2, it is determined that the collision is not detected, and if ΔDC2 is equal to or smaller than Th2, it may be determined that the collision is detected.

  In other words, when combined with the determination of ΔDC1 at T1, it is determined that the biological information detection device has been removed when ΔDC1> Th1 and ΔDC2> Th2, and when ΔDC1> Th1 and ΔDC2 ≦ Th2, an impact is applied instead of removal. It may be determined that is added.

  Further, collision detection may be performed based on a body motion signal from a body motion sensor. As described above, there is a possibility that it may be mistaken for removal when the biological information detection apparatus is lifted, and specifically when a strong impact is applied to the biological information detection apparatus. Therefore, if the biological information detection device includes a motion sensor that detects a motion, the impact can be detected using the motion sensor.

  In order to detect body movement information (for example, information on the number of steps, information on exercise load, etc.) as biological information, or to reduce body movement noise included in the pulse wave sensor signal In many cases, a body motion sensor is provided. Therefore, it is not hindered to separately provide a sensor for detecting an impact, but in many cases, a body motion sensor can be used in combination with an impact detection and other processing. Hereinafter, an example in which an acceleration sensor is used as the body motion sensor will be described.

  Changes in the sensor information (acceleration detection value) of the acceleration sensor when an impact is applied to the biological information detection device every 30 seconds from the time when 60 seconds have passed, as in FIGS. 7A and 7B. Shown in (A). Here, a three-axis acceleration sensor is assumed, and changes in acceleration on each axis of XYZ are shown. Further, FIG. 8B is an enlarged view of a portion where the elapsed time is around 90 seconds in order to see the change in acceleration due to one impact in detail. As can be seen, at the timing corresponding to the impact, the acceleration detection value takes a value of about ± 2 to 4G. Further, from FIG. 8B, it is understood that a signal due to the impact appears in the acceleration detection value within about 1 second after the impact is applied.

  On the other hand, as in FIGS. 10A and 10B, the biological information detection device is removed from the arm when 60 seconds, 120 seconds, and 187 seconds have elapsed, and the biological information is detected when 90 seconds, 150 seconds, and 206 seconds have elapsed. FIG. 11A shows a change in sensor information (acceleration detection value) of the acceleration sensor when the detection device is worn on the arm. Further, FIG. 11B is an enlarged view of a portion where the elapsed time is around 90 seconds in order to see the change in acceleration in one attachment / detachment in detail. As can be seen from this, in the case of attachment / detachment, the change in the acceleration detection value is at most ± 1G.

  That is, the acceleration threshold Thacc is set so as to satisfy 1G ≦ Tacc ≦ 2G, and the absolute value of the acceleration detection value Accmax is compared with Thacc in a period of about 1 second including the timing when the DC component changes. By doing so, collision detection can be performed. Specifically, it is determined that a collision is detected when Accmax> Tacc, and it is determined that no collision occurs when Accmax ≦ Tacc.

  In other words, when combined with the determination of ΔDC1 at T1, it is determined that the biological information detection device has been removed when ΔDC1> Th1 and Accmax ≦ Tacc, and when ΔDC1> Th1 and Accmax> Tacc, it is not a removal but an impact. It may be determined that is added.

  As can be seen from the Z axis acceleration detection value accZ in FIGS. 8B and 11B, when the acceleration detection value itself is used, it is affected by the gravitational acceleration superimposed on the acceleration signal. . Therefore, in order to increase the accuracy of the collision determination using the acceleration detection value, the process may be performed using the discrete differential value of the acceleration detection value instead of the acceleration detection value itself. For example, as a discrete differential value, a difference value between acceleration detection values that are temporally adjacent may be used. FIG. 9A shows a discrete differential value corresponding to FIG. Similarly, FIG. 9B is a discrete differential value corresponding to FIG. 8B, FIG. 12A is a discrete differential value corresponding to FIG. 11A, and FIG. As can be seen by comparing FIG. 9B and FIG. 12B, even when a discrete differential value is taken, Accmax (strictly ΔAccmax) is greater when an impact is applied than when it is removed. Since the gravitational acceleration is canceled by taking the differentiation, the determination becomes more accurate than when the acceleration detection value itself is used.

  Moreover, the method of suppressing the influence by gravity acceleration is not limited to what takes a discrete differential value. For example, the high-pass filter processing may be performed on the acceleration detection value signal shown in FIGS. 8A and 11A, and then the comparison with Thacc may be performed.

3.3 Method Using Auto-Correlation Function of AC Component In the present embodiment, in addition to the above-described method, the auto-correlation function of the AC component signal of the pulse wave sensor signal is used to determine whether the device is mounted or not. Also good.

  Since the AC component of the pulse wave sensor signal in the wearing state is a signal corresponding to the pulse of the user, the signal has periodicity. In addition, when the user wearing the biological information detection device is exercising, the AC component may be superimposed with the signal value of the exercise, but there are many exercises with periodicity such as walking, etc. The AC component signal has periodicity.

  On the other hand, in a non-wearing state, it is difficult to consider a factor that causes the AC component to have periodicity, and the AC component signal generally has no periodicity.

  The autocorrelation function is a function given by the following equation (1), for example. Here, N is a target section, and may be, for example, 64 samples (a section for 4 seconds if the sampling frequency is 16 Hz).

  That is, R (j) is one correlation coefficient between a signal in a certain section of interest and a signal in a section of j samples in the past. The R (j) calculated over j = 1 to N is the autocorrelation function.

  FIGS. 13A and 13B show examples of correlation functions calculated using the above equation (1) and the AC component values shown in FIG. 13A shows a correlation function in a wearing state (90 seconds to 120 seconds in FIG. 10A), and FIG. 13B shows a non-wearing state (60 seconds to 90 seconds in FIG. 10A). Etc.).

  As can be seen from FIG. 13A, the autocorrelation function in the mounted state has a large maximum value and a small minimum value. Specifically, the value range exceeds ± 0.75. Furthermore, the autocorrelation function itself has periodicity. On the other hand, as can be seen from FIG. 13B, the range of the autocorrelation function is narrow in the non-wearing state, and the autocorrelation function has no periodicity. This is because, as described above, the AC component is highly likely to have periodicity in the mounted state, whereas it is considered that there is no periodicity in the non-mounted state.

  Therefore, it is possible to obtain the autocorrelation function of the AC component of the pulse wave sensor signal and determine whether or not the wearing state is based on the autocorrelation function. Specifically, when the maximum value of the autocorrelation function exceeds ± 0.75, when the autocorrelation function has periodicity, or when both are satisfied, the biological information detection device is put into the wearing state. What is necessary is just to determine that there exists. Note that whether or not the autocorrelation function has periodicity may be determined by performing frequency analysis such as FFT.

4). State Transition In this embodiment, it is assumed that the determination process of whether the wearing state or the non-wearing state is performed by using a state machine that determines the output and the next state according to the current state and the input. At that time, not only the wearing state and the non-wearing state but also an intermediate state representing the middle is set. Hereinafter, setting of a state and setting of an event representing an input in each state will be described, and details will be described using a state chart and a flowchart.

4.1 Setting of State and Event FIG. 14 shows a state set in the present embodiment and an example of an event corresponding to an input in each state. As shown in FIG. 14, in this embodiment, the pulse measurement unsuccessful state, the mounted state (certain), the mounted state (suspect), the non-mounted state (reliable), the non-mounted state (suspect), and the measurement End status is set. However, the states and events in the present embodiment are not limited to those in FIG. 14, and various modifications can be made.

  The pulse measurement unsuccessful state (hereinafter also referred to as state A) is a state in which the measurement itself has started, for example, the measurement start button is pressed, but the pulse wave information (pulse rate) has not been successfully measured. .

  The wearing state (reliable) (hereinafter also referred to as state B) is a state where it is certain that the biological information detecting device is attached, and the display of pulse wave information and the like is normally performed. The wearing state (suspect) (hereinafter also referred to as state C) is a state in which the DC component of the pulse wave sensor signal is abnormal, but is being worn. The wearing state (question) is included in the wearing state in a broad sense, but in the sense that a signal that is not seen in the normal wearing state is detected, an intermediate state that is intermediate between the wearing state and the non-wearing state Corresponding to

  The non-wearing state (reliable) (hereinafter also referred to as state D) is a state in which it is certain that the biological information detecting device has been removed. The non-wearing state (probable) (hereinafter also referred to as state E) is a state in which there is a possibility of wearing the biological information detection device, but the detection of pulse wave information has not been successful. The non-wearing state (suspect) may be worn, but is not the same as the wearing state (certain) in that pulse wave information cannot be displayed. That is, the non-wearing state (question) also corresponds to an intermediate state that is intermediate between the non-wearing state and the wearing state.

  The measurement end state (hereinafter also referred to as state F) is a state in which the non-wearing state continues for a long time and the measurement is considered to have ended.

  For each of the states A to E, an event to be monitored in each state is set. In each state, when an event does not occur, the state is continued, and when an event occurs, a process corresponding to the event is performed (output is performed), and a transition is made to another state.

  In the state A, the occurrence of the first pulse measurement success event (event A1) and the measurement unsuccessful constant time continuous event (event A2) are monitored. The event A1 is an event detected when the pulse wave information (pulse) is successfully measured after the transition to the state A. On the other hand, the event A2 is an event that is detected when a certain time elapses without the event A1 occurring after the transition to the state A.

  In state B, the occurrence of a removal event (event B1) and an impact occurrence event (B2) are monitored. The event B1 is an event that is detected when the removal is performed. Specifically, as described above, the event B1 occurs when ΔDC1 is greater than Th1 and no impact is detected. Event B2 is an event detected when an impact occurs. Specifically, ΔDC1 is larger than Th1, but occurs when an impact is detected.

  In state C, the occurrence of a removal event (event C1) and an impact end event (event C2) are monitored. The event C1 is an event detected when the removal is performed in the same manner as the event B1. C1 may be detected by exactly the same process as B1, or threshold values (Th1, Th2, Thacc, etc.) at the time of determination may be changed between C1 and B1. C2 is an event detected when the impact detected when transitioning to state C ends. Specifically, after the transition to the state C, it may be detected on the condition that no impact is detected for a certain period of time, or that there is no abnormality in the value of the DC component (ΔDC1 is small).

  In the state D, the occurrence of the wearing detection event (event D1) and the non-wearing state constant time continuous event (event D2) are monitored. The event D1 is detected when the change value ΔDC3 of the DC component in the given period T3 (the period after the transition to the state D and the length is the same as T1) is larger than the given threshold Th3. The As shown in FIG. 10B, the change value of the DC component upon remounting is smaller than the change value of the DC component upon removal. Therefore, Th3 needs to be small enough to detect even a relatively small change in DC component. This may be realized by setting Th3 and Th1 as a common value and setting Th1 (= Th3) to a value small enough to detect remounting, or setting a threshold value such that Th1> Th3. It may be realized with. In the event D1, it may be used for the determination whether or not the signal value of the DC component is shifted before and after the fluctuation of the DC component, similarly to ΔDC2 at T2. Alternatively, it may be used for determining whether or not the signal value of the DC component after fluctuation is stable, or it may be used for determining whether or not the waveform of the AC component of the pulse wave sensor signal is clean. Whether the waveform is clean or not can be determined using the autocorrelation function as described above.

  The event D2 is an event that is detected when a certain time has passed without the event D1 occurring after the transition to the state D.

  In state E, the occurrence of an external light detection event (event E1) and a midway pulse measurement success event (event E2) are monitored. Event E1 is an event that occurs when external light is detected. Specifically, when the value of the DC component of the pulse wave sensor signal is a value corresponding to a light intensity that is not assumed in the wearing state. Occur. The event E2 occurs when the measurement of the pulse wave information is further successful after the wearing is detected from the state D and the state E is transited. Specifically, the condition is that there is no abnormality in the DC component (ΔDC1 is small), the signal value of the DC component is within a certain numerical range corresponding to the wearing state, and the waveform of the AC component is clean. Occurs when measurement of pulse wave information is successful.

4.2 State Chart FIG. 15 shows a state chart of the present embodiment. As shown in FIG. 15, first, the state A is changed by the measurement start operation event. In state A, when event A1 occurs, the state transitions to state B, and when event A2 occurs, the state transitions to state F.

  In state B, when event B1 occurs, the state transitions to state D, and when event B2 occurs, the state transitions to state C.

  In state C, when event C1 occurs, the state transitions to state D, and when event C2 occurs, the state transitions to state B.

  In state D, when event D1 occurs, the state transitions to state E, and when event D2 occurs, the state transitions to state F.

  In state E, when event E1 occurs, the state transitions to state D, and when event E2 occurs, the state transitions to state B.

  The state B to the state E correspond to the state being measured, and the state is transited until the measurement is completed. Further, the state B corresponds to the mounted state, the state D corresponds to the non-mounted state, and the state C and the state E correspond to the intermediate state. However, considering that the pulse wave information is displayed in the state C and the measurement of the pulse wave information is not successful and the display is not performed in the state E, the state C is in the wearing state in a broad sense. The state E is a close state, and the state E is a state close to a non-wearing state in a broad sense.

  As can be seen from FIG. 15, the transition from the wearing state to the non-wearing state (from state B to state D) may pass through the intermediate state (state C) or directly. This is because it is considered that there is no problem in storing and displaying the pulse wave information even if the transition is made directly from the wearing state to the non-wearing state. On the other hand, the transition from the non-wearing state to the wearing state always passes through the intermediate state (state E). Even if the biological information detection device is attached, it is not possible to measure appropriate pulse wave information immediately, but when a direct transition from the non-wearing state to the wearing state is made, an inappropriate signal is a signal caused by the pulse. This is because there is a risk of misunderstanding.

4.3 Details of Processing The flow of processing according to this embodiment will be described using a flowchart and the like. FIG. 16 shows a flow of basic processing of this embodiment. When this process is started, an event generation process corresponding to the current state is first performed (S101). Details of the processing of S101 are shown in FIG. In the process of S101, first, an event occurrence determination process registered in the current state ID is acquired (S201). For example, if the current state is state A, the respective determination processes of event A1 and event A2 are acquired. Specifically, the determination that the event A1 is determined by determining whether or not the pulse wave information is measured, and the determination of the event A2 is determined by determining whether or not the state A continues for a certain period of time. What is necessary is just to acquire information. Then, based on the information acquired in S201, it is determined whether or not an event has actually occurred (S202). If it is determined in S202 that any event has occurred, the ID of the event is returned (S203).

  After the process of S101, it is determined whether an event has occurred (S102). This may be determined in S203 as to whether or not a specific event ID has been returned. If any event has occurred, an event occurrence associated process, which is a process associated with the event, is performed (S103).

  Details of the process of S103 are shown in FIG. In the event generation accompanying process, a ripple process to the external operation process associated with the event ID is executed (S301), a UI process associated with the event ID is executed (S302), and the event ID is associated with the event ID. State transition processing is executed (S303). However, the order of S301 to S303 is not limited to this, and the spreading process, UI process, and state transition process may be executed in an order different from that in FIG.

  As shown in FIG. 20A, the spreading process is a process in which the result of attachment / detachment detection is propagated to different processes, such as a noise filter and a pulse determination process. Specifically, when the pulse wave information calculated by the pulse wave information calculation process is stored in the storage unit 300 or transmitted to another electronic device via the communication unit 400, the pulse wave information is not attached. A process of associating information indicating that it has been acquired in the state may be performed. Alternatively, initialization of parameters in pulse wave information calculation processing and initialization of a noise filter that reduces body movement noise and other noises (for example, initialization of filter coefficients) may be performed.

  An example of parameter initialization will be described with reference to FIGS. 21 (A) and 21 (B). The parameter here may be a window representing a range in which it is estimated that there is a pulse frequency when the AC component of the pulse wave sensor signal is subjected to frequency analysis. FIGS. 21A and 21B show examples of the results of frequency analysis of AC components. When the pulse frequency is obtained at a given timing as shown in FIG. 21A, a window representing, for example, ± 3 ranges of the pulse frequency may be set. At subsequent timings, the frequency within the window range is preferentially estimated as the pulse frequency. This is based on the idea that the frequency of a human pulse does not change rapidly in a short time. For example, it is unlikely that a user who has a pulse rate of 60 at a certain timing will have a pulse rate of 150 at the next timing, and a pulse rate close to 60 is assumed at the next timing.

  By setting such a window, it is possible to estimate the pulse frequency even when the influence of noise or the like is strong and the frequency peak cannot be clearly determined as shown in FIG. . In the example of FIG. 21B, the difference between the large value and the small value of the power value is small, and there is a frequency at which the power is maximum outside the window range. Even in such a case, if a window is set based on FIG. 21A, a plausible frequency can be estimated as a pulse frequency.

  However, such a window is a parameter used to estimate some peak even if the peak is not clear. As a result, even if the biological information detection device is in a non-wearing state and a signal due to the pulse cannot actually be acquired, the peak is forcibly estimated by the effect of the window, and the pulse frequency is obtained. There is a possibility of misunderstanding. Therefore, in the present embodiment, when an event in the direction of shifting to the non-wearing state occurs, the window may be initialized. In this case, in the case as shown in FIG. 21B, it is possible to output pulse wave information measurement failure or the like without forcibly estimating the pulse frequency.

  Further, in the present embodiment, an adaptive enhancer (adaptive filter in a broad sense) may be used to reduce body motion noise included in the pulse wave sensor signal and other various noises. The adaptive enhancer predicts the noise signal using a linear integration of past samples in a process of separating the measured signal value into a target signal and a noise signal having periodicity. That is, the filter coefficient of the adaptive filter which is an adaptive enhancer is determined based on the past signal value.

  In determining the filter coefficient, it is necessary to use a signal in which noise is superimposed on a signal caused by a pulse as the measured signal value. However, in the non-wearing state, a signal due to the pulse is not acquired in the first place, and the measured signal value includes a signal that is not assumed in the wearing state, such as external light. That is, if learning of the adaptive enhancer is performed using the measurement value in the non-wearing state, the accuracy of the adaptive enhancer decreases. Therefore, in this embodiment, in a scene corresponding to the non-wearing state, the adaptive enhancer may be initialized (in a narrow sense, the filter coefficient of the adaptive filter is initialized). Alternatively, since learning using an inappropriate signal is not performed, a ripple process for stopping learning of the adaptive enhancer may be performed in a scene corresponding to a non-wearing state.

  UI processing is processing for notifying the user that a given event has occurred, as shown in “screen”, “sound”, “vibration”, and the like in FIG. Note that the UI processing is not limited to screen display and generation of sound and vibration, but includes all processing that affects the user's perception as a result, such as notification by light or data transmission to other electronic devices.

  The state transition processing is processing for transitioning the state from the current state to another state as described above using the state chart.

  In the case of No in S102, or after the process of S103, a state associated process is performed (S104). That is, in the case of No in S102, since the state transition is not performed, the process accompanying the original state is performed, and in the case of Yes in S102 and the process of S103 being performed, the state transition process of S303 is performed. The process associated with the previous state after the transition is performed. Details of the processing of S303 are shown in FIG. In the state accompanying process, a ripple process to the external calculation process associated with the state ID is executed (S401), and a UI process associated with the state ID is executed (S402). The spreading process and UI process are the same as the event occurrence accompanying process. A detailed example of the spreading process and the UI process in the state accompanying process is shown in FIG. In the spreading process, the parameter initialization process or the filter coefficient initialization process in the pulse wave information calculation process described above may be performed. In particular, considering that it is desirable to perform these processes in a non-wearing state, it is not a process accompanied by an event occurrence, but a state-accompanying process corresponding to a non-wearing state (including not only the state D but also the state E). Also good.

  In the processing of the present embodiment, the basic processing flow shown in FIG. 16 is periodically executed. In the example of FIG. 16, the event-accompanying process is performed only when an event occurs, and the state-associated process is performed every time the basic process flow is executed, but the present invention is not limited to this. For example, the state-accompanying process may be performed only when an event occurs (in a narrow sense, when a state transition occurs).

5. Specific Example of the Present Embodiment In the present embodiment described above, the biological information detection apparatus includes a pulse wave detection unit 10 that outputs a pulse wave sensor signal and a processing unit 100 that processes the pulse wave sensor signal, as shown in FIG. including. And the process part 100 performs the removal detection process of a biological information detection apparatus based on the change value of DC component of the pulse-wave sensor signal in a given period. The pulse wave detection unit 10 may include a pulse wave sensor 11 as shown in FIG.

  Thereby, it is possible to detect the removal of the biological information detecting device based on the change value (specifically, the above-described ΔDC1) of the DC component of the pulse wave sensor signal in a given period (specifically, the above-described T1). become. As shown in Patent Document 1, it is known that the signal value of the DC component itself is different between the wearing state and the non-wearing state, but the signal value of the DC component varies depending on various factors. For this reason, it is difficult to set a threshold value for clearly discriminating between the signal value in the wearing state and the signal value in the non-wearing state in various situations. On the other hand, if the change value of the DC component is used, the fluctuation due to the above various factors is added to both the signal values before and after the change.

  The evaluation results of the method of this embodiment are shown in FIGS. 22 (A) to 22 (C). 22 (A) to 22 (C), the elapsed time is from 0 second to 60 seconds in the wearing state, and then from 60 seconds to 120 seconds, the wearing state is kept, and the biological information detection device is held in hand. It is an example of various signal values at the time of performing the operation | movement which hold | grips and shakes, and performs the mounting | wearing again after 120 seconds. FIG. 22A is a diagram showing the AC component and DC component of the pulse wave sensor signal, and FIG. 22B is a diagram showing the change value ΔDC1 of the DC component. FIG. 22C is a diagram comparing changes in the pulse rate measured in such a situation between the conventional method and the method of the present embodiment.

  In the conventional method, as described above, there is a problem in the accuracy of detection of removal, so that after 60 seconds have passed, the device is not attached and an appropriate pulse rate cannot be obtained, but the removal cannot be detected and some pulse rate cannot be detected. Has been estimated and output. This is because, as described above with reference to FIGS. 21A and 21B, parameters (windows) are set so that some value can be easily estimated even if noise is large. Also, an abnormal pulse rate is output, such as from about 130 seconds to about 170 seconds. This is presumed to have been affected by a change in the pulse wave sensor signal due to re-mounting after 120 seconds.

  On the other hand, in the method of the present embodiment, as shown in FIG. 22B when 60 seconds and 120 seconds have elapsed, the change value of the DC component at the time of removal (and remounting) that shows a remarkable value compared with the normal time. Since the process is performed using the, removal detection can be performed with high accuracy. Specifically, as shown in FIG. 22C, the pulse rate is set to 0 (unmeasurable) in the removal period after 60 seconds.

  In addition, when trying to make a high-precision determination using the conventional method, it is possible to determine that removal has been detected when multiple detection determinations are made, or to combine multiple detection methods from multiple viewpoints. When detection determination is performed, it is necessary to use a method of determining that removal has been detected. For this reason, there is often a time lag after the actual removal process is performed until the biological information detection device detects the removal. On the other hand, with the method of the present embodiment, the removal can be detected in a short time as shown in FIG. In the example of FIG. 22C, removal has already been detected at the next processing timing of 60 seconds. In FIG. 22 (C), it takes some time until the pulse rate can be measured after remounting after 120 seconds. This is mainly a time lag for accumulating pulse wave sensor signals necessary for calculating pulse wave information. The timing at which an appropriate pulse waveform can be obtained as a result of the remounting can be detected in a short time.

  In addition, the processing unit 100 changes the DC component change value of the pulse wave sensor signal in a given period, and the pulse wave in the second period that includes the given period and is longer than the given period. The removal detection process may be performed based on a second change value representing a change in the DC component of the sensor signal.

  Here, the second period corresponds to T2 shown in FIGS. 6A, 6B, and the like, and in a narrow sense, before and after the change of the signal value of the DC component in a given period T1. This is a period including a later stable period. The second change value that is the change value in the second period is specifically the first timing included in T2, as shown in FIGS. 6A and 6B. It is a difference value between the DC component value and the DC component value at the second timing included in T2. More specifically, it is included in the DC component value at the first timing, which is the timing included in the stable state (stable period) of the DC component before T1, and included in the stable period of the DC component after T1. It is a difference value from the DC component value at the second timing which is the timing.

  Thus, the removal detection process is performed using not only the change value ΔDC1 of the DC component at T1, which is a relatively short period, but also the change value ΔDC2 of the DC component at T2, which includes T1 and is longer than T1. It becomes possible. As shown in FIG. 6A and FIG. 6B, when the detachment is actually performed and when the biological information detection device is temporarily lifted with respect to the skin due to the impact. , ΔDC1 is a large value to some extent, whereas the value of ΔDC2 is greatly different. Therefore, it is possible to suppress the possibility of erroneous detection that temporary floating due to impact is removal, and to perform removal detection processing with higher accuracy.

  Further, the processing unit 100 determines that the change value of the DC component of the pulse wave sensor signal in a given period exceeds a given threshold value, and the second change value in the second period exceeds a second threshold value. In this case, it may be determined that the biological information detection device has been removed.

  Thereby, in addition to the comparison process between ΔDC1 and Th1, the removal detection process can be performed by performing a comparison process between ΔDC2 and the second threshold value Th2. As shown in FIGS. 6 (A) and 6 (B), ΔDC2 is close to 0 when an impact is applied, whereas it is somewhat large when removal is performed. Become. Therefore, if ΔDC1> Th1 and ΔDC2 ≦ Th2, it is determined that an impact has been applied, and if ΔDC1> Th1 and ΔDC2> Th2, it may be determined that removal has been performed.

  Moreover, the biological information detection apparatus may further include a body motion sensor 21 that outputs a body motion signal, as shown in FIG. Then, the processing unit 100 causes the change value of the DC component of the pulse wave sensor signal in a given period to exceed a given threshold, and the body motion signal in a period corresponding to the given period is a given body movement. If it is equal to or less than the threshold value, it is determined that the biological information detection device has been removed.

  Thereby, it is determined using the body motion signal whether the change in the signal value of the DC component is due to actual removal or due to the floating or deviation of the biological information detection device due to the impact. Is possible. Specifically, as can be seen from the comparison between FIG. 8B and FIG. 11B, when the removal is performed, the change in the acceleration signal is at most about ± 1 G, while an impact is applied. If it is, it will be about ± 2-4G. The impact determination may be performed based on the difference between the acceleration detection values. Specifically, when the acceleration detection value (the maximum value in a narrow sense) Accmax is equal to or less than a given acceleration threshold value Thacc, it is determined that there is no impact. To do. That is, it may be determined that there has been removal when ΔDC1> Th1 and Accmax ≦ Thacc. Note that, as described above with reference to FIGS. 9B and 12B, the determination may be made using the change value of the body motion signal, not the body motion signal (acceleration detection value in a narrow sense) itself. Good.

  In addition, when the removal of the biological information detection device is detected by the removal detection process, the processing unit 100 may perform a parameter initialization process in the pulse wave determination process based on the pulse wave sensor signal.

  Specifically, the processing unit 100 sets a window corresponding to a given frequency range including the frequency determined as the pulse frequency in the past pulse wave determination processing, and preferentially selects the frequency included in the window. The processing for determining the frequency is performed as pulse wave determination processing based on the pulse wave sensor signal, and the processing unit 100 performs window initialization processing when the removal of the biological information detection device is detected by the removal detection processing. May be.

  Thereby, when removal is detected, that is, when the biological information detection device is not attached, it is possible to perform parameter initialization processing in the pulse wave determination processing. The parameter here may be, for example, the window described above with reference to FIGS. 21 (A) and 21 (B). This window enables estimation of the pulse frequency even when there is a lot of noise as shown in FIG. 21B and it is difficult to determine the peak frequency of the AC component. Therefore, if the window is continuously used even in the non-wearing state, there is a case where some pulse frequency is obtained although a signal due to the pulse is not acquired. In the present embodiment, the parameters are initialized in the non-wearing state to prevent inappropriate estimation of the pulse frequency in the non-wearing state.

  In addition, when the removal of the biological information detection device is detected by the removal detection process, the processing unit 100 may perform an initialization process of the filter coefficient of the adaptive enhancer applied to the pulse wave sensor signal.

  As a result, when removal is detected, that is, when the biological information detection device is not attached, it is possible to perform initialization processing of the filter coefficient of the adaptive enhancer. The adaptive enhancer separates the noise signal under the assumption that the signal due to the pulse and the noise signal are superimposed on the signal to be measured, and obtains the signal due to the pulse. That is, if learning of the filter coefficient of the adaptive enhancer is performed in a non-wearing state, a measurement signal that does not include a pulse signal is used, and the accuracy of the adaptive enhancer (for example, noise reduction accuracy) is increased. It will decline. In this embodiment, the filter coefficient is initialized in the non-wearing state, thereby suppressing inappropriate learning of the adaptive enhancer in the non-wearing state. In addition, since the filter coefficient acquired based on the information in the non-wearing state only needs to be initialized, it is not always necessary to perform the initialization process in the non-wearing state. For example, the initialization process may be performed every given period, or the initialization process is performed at a timing at which remounting is detected after detection of removal (timing in a narrow sense is a transition from state D to state E). May be performed.

  Further, the process related to the adaptive enhancer when the removal of the biological information detection device is detected is not limited to the filter coefficient initialization process. For example, the processing unit 100 may stop the adaptation process of the adaptation enhancer applied to the pulse wave sensor signal when the removal of the biological information detection device is detected by the removal detection process.

  As described above, by performing learning (adaptive processing) of the adaptive enhancer using information in the non-wearing state, the accuracy of the adaptive enhancer may be reduced. In other words, if it is possible to avoid learning in the non-wearing state, it is possible to suppress the degradation of the accuracy of the adaptive enhancer, and therefore it is not always necessary to perform the filter coefficient initialization process. Specifically, the learning may be temporarily stopped when the removal of the biological information detection device is detected. Note that the learning is resumed when a given period has elapsed or when the re-installation of the biological information detection device is detected (in a narrow sense, when a transition from the state D to the state E is performed). Good. It should be noted that the filter coefficient initialization process and the learning stop process are not limited to those that perform either one, but after performing the stop process, a modified implementation such as performing the filter coefficient initialization process when learning resumes may be performed. Is possible.

  In addition, the processing unit 100 includes the i-th DC component value at the i-th (i is a positive integer) sampling timing of the pulse wave sensor signal and the j-th (j is an integer satisfying j> i) of the pulse wave sensor signal. The difference value from the j-th DC component value at the sampling timing of) may be obtained as a change value of the DC component, and the removal detection process may be performed based on the obtained change value of the DC component.

  Thereby, as shown in FIG. 5A or FIG. 5B, the difference between the DC component values at a plurality of sampling timings as the change value ΔDC1 of the DC component of the pulse wave sensor signal in a given period T1. The value can be used. As shown in FIG. 5A, if the difference value at the adjacent sampling timing (when j = i + 1) is used, the removal detection process is performed at a higher speed than in the case of FIG. 5B. Is possible. Further, as shown in FIG. 5B, if difference values at non-adjacent sampling timings (in the case of j> i + 1) are used, the DC component changes as in the case where the change of the DC component extends over a plurality of sampling timings. Even when the signal value undergoes a relatively gentle change, the change value ΔDC1 can be obtained appropriately.

  Further, the processing unit 100 may determine that the biological information detection device has been removed when the change value of the DC component of the pulse wave sensor signal in a given period exceeds a given threshold value.

  This makes it possible to detect removal based on a comparison process between the change value ΔDC1 of the DC component and a given threshold value Th1. As shown in FIG. 4 and the like, ΔDC1 at the timing corresponding to the removal is sufficiently larger than a value close to 0 in normal times. Therefore, an appropriate threshold value Th1 is set and ΔDC1> Th1. What is necessary is just to determine with having removed.

  In addition, the processing unit 100 is based on a third change value that represents a change in the DC component of the pulse wave sensor signal in a third period that is a period after the removal of the biological information detection device is detected by the removal detection process. Then, the reattachment detection process of the biological information detection apparatus may be performed.

  Thereby, based on the change value of the DC component, not only the removal of the biological information detection device but also the detection of remounting can be performed. In addition, in the case where the biological information detection device is left on the desk in a non-wearing state, and a person passes near the biological information detection device, a part of the external light is caused by the person. Is shielded, there is a possibility that the change value ΔDC3 of the DC component becomes large. In this case, there is a risk of making an erroneous determination that the state has shifted to the mounted state even though the non-mounted state continues. Therefore, similarly to the example of the impact detection in the removal determination, the change value ΔDC4 of the DC component in the period T4 including T3 and longer than T3 may be obtained, and remounting may be determined using both ΔDC3 and ΔDC4. Specifically, when given threshold values are Th3 and Th4, it is determined that remounting is performed when ΔDC3> Th3 and ΔDC4> Th4. If the outside light is temporarily shielded by a person or the like, the signal value of the DC component returns to its original value when the shielding factor is removed. Therefore, ΔDC4 is close to 0, but remounting is performed. This is because the signal value of the DC component is considered to shift.

  In addition, when ΔDC3> Th3 and the waveform of the AC component is clean, various modifications such as determining that remounting has been performed are possible. A clean AC component waveform corresponds to a case where the autocorrelation function of the AC component is as shown in FIG.

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

10 pulse wave detector, 11 pulse wave sensor, 12 LED, 13 PD, 14 convex part,
16 A / D conversion unit, 20 body motion detection unit, 26 A / D conversion unit, 100 processing unit,
110 attachment / detachment detection unit, 120 pulse wave information calculation unit, 200 display unit, 300 storage unit,
400 communication unit, 500 base unit, 600 holding mechanism

Claims (7)

A pulse wave detector for outputting a pulse wave sensor signal;
A processing unit for processing the pulse wave sensor signal;
Including
The pulse wave detection unit includes a light emitting unit and a light receiving unit,
The processor is
A biometric information detection apparatus that performs UI processing when detection of removal of the biometric information detection apparatus is detected based on a change value of a DC component of the pulse wave sensor signal when the light emitting unit is turned on. In claim 1,
A display unit for displaying a calculation result in the processing unit;
The processor is
The biological information detection apparatus characterized by blinking the icon displayed on the said display part as said UI process. In claim 1 or 2,
Including a notification unit that generates at least one of sound and vibration,
The processor is
The biological information detection apparatus characterized in that at least one of sound and vibration is generated by the notification unit as the UI processing. In any one of Claims 1 thru | or 3,
The processor is
A biological information detection device that turns off the light emitting unit or turns on a low current when detecting the removal of the biological information detection device based on a change value of the DC component of the pulse wave sensor signal. In any one of Claims 1 thru | or 4,
A body motion sensor for outputting a body motion signal;
The processor is
When the change value of the DC component of the pulse wave sensor signal exceeds a given threshold value and the body motion signal is equal to or less than the given body motion threshold value, it is determined that the biological information detection device has been removed. A biological information detection apparatus characterized by the above. In any one of Claims 1 thru | or 4,
A body motion sensor for outputting a body motion signal;
The processor is
Calculate the number of steps based on the body motion signal,
The biological information detection apparatus, wherein when the removal of the biological information detection apparatus is detected based on a change value of the DC component of the pulse wave sensor signal, the total number of steps is stopped. In any one of Claims 1 thru | or 6.
The processor is
Wherein After detecting the removal of the living body information detection apparatus, when the state of the removal is continued for a certain time, the biological information detection apparatus, characterized in that to terminate the measurement.

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