JP2018061781A - Biological information acquisition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a reduction in accuracy of biological information due to noise of a vehicle.SOLUTION: A biological information acquisition device includes: a first body motion detection section (38) having a first pressure-sensitive part (35) on which body motion of a living body (1) in a vehicle (10) acts and outputting a first signal corresponding to the body motion acting on the first pressure-sensitive part (35); a second body motion detection section (48) having a second pressure-sensitive part (45) on which the body motion of the living body (1) in the vehicle (10) acts and outputting a second signal corresponding to the body motion acting on the second pressure-sensitive part (45); an adaptive filter (57) for processing the second signal so as to reduce an error signal being a difference between the first signal and the second signal after adaptively processing; and a biological information acquisition section (60) for obtaining biological information of the living body (1) on the basis of the error signal.SELECTED DRAWING: Figure 1

Description

    The present invention relates to a biological information acquisition apparatus that acquires biological information of a biological body on a vehicle.

    There is a biological information acquisition device that acquires biological information of a biological body on a vehicle. For example, Patent Document 1 discloses an apparatus that acquires biological information of a driver on a vehicle of an automobile.

    In this biological information acquisition apparatus, a pressure sensitive part is attached to the lower part of the driver seat. The pressure sensitive part is constituted by a hollow air bag. When the driver's body movement (fine movement derived from heartbeat or breathing) is transmitted to the pressure-sensitive part, the internal pressure of the pressure-sensitive part changes. The biological information acquisition device detects the internal pressure of the pressure-sensitive unit and generates a signal (biological signal) corresponding to the internal pressure. Thereby, the biometric information acquisition apparatus obtains the driver's biometric information (for example, information on heartbeat and respiration) based on the biomedical signal.

JP 2012-105835 A

    By the way, when the vehicle is traveling, vibrations other than body movements of the living body act on the pressure sensitive part as noise. This noise includes road noise generated when the vehicle travels on the road, engine noise caused by vibration of the vehicle engine, and the like. When such noise acts on the pressure-sensitive part, a signal (referred to as a noise signal) resulting from the noise is superimposed on the detected signal, so that the biological signal cannot be detected accurately, and the accuracy of the biological information decreases. There is a possibility that.

    This invention is made | formed in view of such a point, The objective is suppressing the fall of the precision of biometric information resulting from the noise of a vehicle in a biometric information acquisition apparatus. .

    A first invention is directed to a biological information acquisition device, and includes a first pressure sensing part (35) on which a body motion of a living body (1) on a vehicle (10) acts, and the first pressure sensing part (35 ) A first body motion detector (38) that outputs a first signal corresponding to the body motion acting on the second body (1), and a second pressure sensing unit (where the body motion of the living body (1) on the vehicle (10) acts) 45), a second body motion detector (48) for outputting a second signal corresponding to the body motion acting on the second pressure sensor (45), the first signal, and after the adaptive processing An adaptive filter (57) that processes the second signal so as to reduce an error signal that is a difference from the second signal, and biometric information acquisition for obtaining biological information of the living body (1) based on the error signal Part (60).

    In the first invention, the body movement of the living body (1) acts on the first pressure-sensitive part (35) and the second pressure-sensitive part (45), respectively. The first body motion detector (38) outputs a first signal corresponding to the body motion acting on the first pressure sensor (35), and the second body motion detector (48) is a second pressure sensor. The second signal corresponding to the body movement acting on (45) is output. Here, strictly speaking, the first pressure-sensitive part (35) and the second pressure-sensitive part (45) are arranged at different locations. For this reason, body movements (for example, movements associated with heartbeat and respiration) that occur from the living body (1) may act on the first pressure sensing part (35) and the second pressure sensing part (45) in exactly the same way. I don't get it. Therefore, the behavior of the biological signal is different between the first signal corresponding to the first pressure sensitive part (35) and the second signal corresponding to the second pressure sensitive part (45). At this time, if vibration that causes road noise, engine noise, or the like occurs, this vibration also acts on the first pressure-sensitive portion (35) and the second pressure-sensitive portion (45). For this reason, a noise signal is also superimposed on the first signal and the second signal.

    In the present invention, adaptive processing based on the first signal and the second signal is performed by the adaptive filter (57). Specifically, the adaptive filter (57) adapts the second signal so that an error signal (also referred to as a cancel signal or an error signal) that is a difference between the first signal and the second signal after the adaptive processing is reduced. Process. That is, the adaptive filter (57) appropriately updates the filter coefficient according to the optimization algorithm so that the waveform of the second signal approaches the waveform of the first signal.

    Here, in the first signal and the second signal, the noise signal is superimposed together with the biological signal as described above. Here, the level of the noise signal is extremely higher than the level of the biological signal resulting from respiration or heartbeat. In addition, the behavior of the biological signals of the first signal and the second signal is not exactly the same. For this reason, when adaptive processing is performed based on these signals, a noise signal having an extremely large level can be canceled, while biological signals having low levels and different behaviors between the two signals remain as error signals. . Therefore, the biological information acquisition unit (60) obtains the biological information of the biological body (1) based on the error signal. Since this error signal is a state in which the noise signal is canceled and the biological signal remains, even if noise is generated on the vehicle (10), highly accurate biological information can be obtained.

    According to a second invention, in the first invention, one of the first pressure sensing part (35) and the second pressure sensing part (45) is attached to the living body (1), and the first pressure sensing part (35 ) And the second pressure sensing part (45) are provided on the seat (11) of the vehicle (10). Here, “attached to a living body” as defined in the present invention refers to the living body (1) so that the first pressure-sensitive part (35) and the second pressure-sensitive part (45) directly touch the living body (1). In addition to being attached, this means that the first pressure-sensitive part (35) and the second pressure-sensitive part (45) are attached to the living body (1) via clothes or the like.

    In the second invention, the body motion of the living body (1) directly acts on the pressure sensitive part (35, 45) attached to the living body (1). On the other hand, the body movement of the living body (1) indirectly acts on the pressure sensitive part (35, 45) provided on the seat (11). For this reason, the difference in the behavior of the biological signal becomes large between the first signal and the second signal. As a result, it is possible to suppress cancellation of the biological signal in the error signal after the adaptive processing, and the biological signal is likely to remain in the error signal.

    According to a third invention, in the first invention, one of the first pressure sensing part (35) and the second pressure sensing part (45) is provided on a handle (14) of the vehicle (10), and the first pressure sensing part (35) is provided. The other of the pressure sensing part (35) and the second pressure sensing part (45) is provided in the seat (11) of the vehicle (10).

    In the third invention, when the living body (1) grips the handle (14), the body movement of the living body (1) directly acts on the pressure sensitive part (35, 45) in the handle (14). On the other hand, the body movement of the living body (1) indirectly acts on the pressure sensitive part (35, 45) provided on the seat (11). For this reason, the difference in the behavior of the biological signal becomes large between the first signal and the second signal. As a result, it is possible to suppress cancellation of the biological signal in the error signal after the adaptive processing, and the biological signal is likely to remain in the error signal.

    In a fourth aspect based on the first aspect, both the first pressure sensing part (35) and the second pressure sensing part (45) are provided in the seat (11) of the vehicle (10).

    In the fourth invention, since both the first pressure sensing part (35) and the second pressure sensing part (45) are provided in the seat (11) of the vehicle (10), the living body (1) is provided with each pressure sensing part ( 35,45) becomes difficult to notice. Therefore, the comfort of the living body (1) on the vehicle (10) can be improved.

    In a fifth aspect based on the first or second aspect, the first pressure sensitive part (35) is attached to the living body (1).

    In the fifth invention, the first pressure sensitive part (35) is attached to the living body (1). For this reason, the 1st signal outputted from the 1st pressure sensing part (35) becomes difficult to be influenced by the posture and seating position of living body (1). Here, the first signal is a main signal before noise is removed by adaptive processing. Therefore, by obtaining the first signal by the wearable pressure-sensitive part (35, 45), it is possible to suppress a decrease in the accuracy of the biological information due to a change in the posture or sitting position of the living body (1).

    In a sixth aspect based on the first or third aspect, the first pressure sensing part (35) is provided on a handle (14) of the vehicle (10).

    In the sixth invention, the first pressure sensing part (35) is provided on the handle (14). For this reason, the biological signal is surely superimposed on the first signal output from the first pressure sensing unit (35). Here, the first signal is a main signal before noise is removed by adaptive processing. Therefore, by obtaining the first signal by the pressure-sensitive part (35, 45) of the handle (14), the biological information can be reliably acquired.

    According to a seventh invention, in any one of the first to sixth inventions, the biological information acquisition unit (60) is the biological information most of the error signal and at least one of the first signal and the second signal. The determination unit (63) for determining a highly accurate signal is obtained, and the biological information of the living body (1) is obtained using the highly accurate signal determined by the determination unit (63).

    In the seventh invention, the biological information is obtained using the error signal obtained by the adaptive processing and the signal having the higher accuracy of at least one of the first signal and the second signal. For example, in a situation where noise hardly occurs, such as when the vehicle (10) is stopped, the biological signal may appear more clearly in the first signal and the second signal than in the error signal after the application process. Further, for example, in a transient situation where the speed of the vehicle (10) and the posture of the living body (1) change greatly, the adaptive processing cannot sufficiently catch up and the waveform of the error signal may be disturbed. For this reason, the determination unit (63) of the present invention determines a signal with higher accuracy among the error signal and at least one of the first signal and the second signal. Then, the biological information acquisition unit (60) acquires the biological information of the living body (1) using a signal having higher accuracy among these signals. As a result, the accuracy of biological information is further improved.

    In an eighth aspect based on the seventh aspect, the determination unit (63) determines a signal having high accuracy of biological information from the three signals of the error signal, the first signal, and the second signal. To do.

    In the eighth aspect, since the biological information is obtained from the signal having the highest accuracy among the three signals including the error signal, the first signal, and the second signal, the accuracy of the biological information is further improved.

In a ninth aspect of the present invention, the determination unit (63) includes the pressure signal (35, 45) provided in the seat (11) of the vehicle (10) among the error signal and the first signal and the second signal. A signal with high accuracy of biological information is determined from the signals corresponding to the signal, and heart rate information of the living body (1) is obtained using the signal with high accuracy. In the ninth invention, the error signal and the seat (11) Among the signals corresponding to body movements acting on the pressure-sensitive parts (35, 45), heartbeat information is obtained using a signal with higher accuracy. For example, in a situation where little noise is generated when the vehicle (10) is stopped, the respiratory component in the detected signal tends to be prominent. This is because the level of the respiratory component is larger than the level of the heart rate component. For this reason, in such a situation, it becomes difficult to extract a heartbeat component due to an increase in the respiratory component in the biological signal, and there is a possibility that the detection accuracy of the heartbeat information is lowered. On the other hand, the pressure-sensitive part (35,45) in the seat (11) is not easily transmitted with fine movements derived from the breathing of the living body (1). The respiratory component becomes smaller. As a result, the heart rate signal of the living body (1) can be reliably detected by the pressure sensing unit (35, 45), and the accuracy of the heart rate information is improved.

    On the other hand, in a situation where noise is large, such as when the vehicle (10) is traveling, the error signal is used, so that heartbeat information can be detected with high accuracy while canceling noise.

    In a tenth aspect based on any one of the seventh to ninth aspects, the determination unit (63) indicates the error signal and biological information of at least one of the first signal and the second signal. The frequency distribution of the index is obtained, and the signal having the highest ratio of the mode distribution to the total frequency of the frequency distribution is determined as the highly accurate signal.

    In the tenth invention, the determination unit (63) obtains the frequency distribution of the index indicating the biological information. Then, the determination unit (63) determines that the signal having the highest ratio of the mode distribution to all frequencies is a highly accurate signal. That is, a signal having a high ratio of the mode distribution with respect to all frequencies can be regarded as sufficiently representing a trend of biological information (heartbeat and respiration) without being affected by disturbances such as noise. Therefore, the determination unit (63) determines such a signal as the signal with the highest accuracy. A biometric information acquisition part (60) calculates | requires biometric information using this signal.

    According to the present invention, the adaptive processing is performed based on the signals detected by the two pressure sensing units (35, 45), and the biological information is acquired based on the error signal after the adaptive processing. As a result, noise such as road noise and engine noise can be canceled, and detection accuracy of biological information can be improved. In the present invention, an acceleration sensor for canceling noise is also unnecessary. Therefore, noise can be canceled with a relatively simple configuration.

FIG. 1 is a schematic diagram showing the inside of a vehicle to which the biological information acquisition apparatus is applied. FIG. 2 is a block diagram illustrating a schematic configuration of the biological information acquisition apparatus. FIG. 3 is a perspective view showing a schematic configuration of the first pressure-sensitive unit. FIG. 4 is a longitudinal sectional view showing a schematic configuration of the second pressure-sensitive unit. FIG. 5 is a block diagram showing the flow of adaptive processing. FIG. 6 is a schematic diagram for explaining the concept of the waveforms of the first signal, the second signal, and the cancel signal. FIG. 7 is a diagram corresponding to FIG. 1 illustrating another arrangement of the pressure-sensitive unit. FIG. 8 is a diagram corresponding to FIG. FIG. 9 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

    This embodiment is a biological information acquisition device (20) for a vehicle that acquires biological information of the biological body on the vehicle. The biological information acquisition device (20) of this embodiment is applied to an automobile (10) that is a vehicle, and acquires heart rate information of a driver (1) that is a living body as biological information.

    As shown in FIG. 1, the biological information acquisition device (20) includes a first pressure sensitive unit (30), a second pressure sensitive unit (40), and one signal processing unit (50). In the present embodiment, the first pressure-sensitive unit (30) is configured to be mounted on the driver (1), and the second pressure-sensitive unit (40) is provided on the seat (11) of the automobile (10). It is configured as a stationary type. The seat (11) has a seat (12) on which the driver (1) is seated and a backrest (13) that receives the back of the driver (1). A handle (14) operated by the driver (1) is provided on the front side of the seat (11).

<First pressure sensitive unit>
As shown in FIG.1 and FIG.3, a 1st pressure sensitive unit (30) is provided in the belt (2) attached to the trousers of a driver | operator (1). The first pressure-sensitive unit (30) has an attachment member (31) and a first pressure-sensitive tube (35) fixed to the attachment member (31).

    The attachment member (31) is a clip type attached by sandwiching the belt (2). Specifically, the attachment member (31) has a quadrangular columnar base (32) formed on the upper side thereof and a pair of plate portions (33, 33) extending downward from the base (32). . The pair of plate portions (33, 33) extend in parallel at a predetermined interval, and an insertion port (34) into which the belt (2) is inserted is formed therebetween.

    The first pressure sensing tube (35) constitutes a hollow first pressure sensing part on which the body movement of the driver (1) acts. The first pressure-sensitive tube (35) is formed in an elongated hollow tube shape. The first pressure-sensitive tube (35) is made of a flexible resin material (for example, a vinyl chloride material). The tip (one end) of the first pressure-sensitive tube (35) is sealed with, for example, a stopper (not shown). You may form the small hole which connects the inside and exterior of a 1st pressure sensing tube (35) to this stopper. The base end (other end) of the first pressure sensing tube (35) is connected to the signal processing unit (50).

    The first pressure-sensitive tube (35) has a first pressure-sensitive part main body (36) disposed on the back surface of the mounting member (31). The first pressure-sensitive portion main body (36) is formed in a U shape along the inner plate portions (33, 33). The first pressure-sensitive part main body (36) is located inside the belt (2) and is in close contact with the abdomen or waist of the driver (1). As a result, the body movement of the driver (1) (fine movement derived from breathing and heartbeat) acts on the first pressure sensing tube (35), and the internal pressure of the first pressure sensing tube (35) changes accordingly.

<Second pressure sensitive unit>
As shown in FIG.1 and FIG.4, a 2nd pressure sensitive unit (40) is provided in the seat part (12) where a driver | operator (1) seats among the seats (11) of a motor vehicle (10). The second pressure-sensitive unit (40) of this embodiment is a cushion-type that is laid on the seat (12). Specifically, the second pressure sensing unit (40) includes a cushion (41) installed on the surface of the seat (12) and a pair of pressure receiving plates (42, 42) embedded in the cushion (41). ) And a second pressure sensing tube (45) fixed to the cushion (41).

    The cushion (41) is made of, for example, a flexible urethane material, and an internal space (43) is formed below the cushion (41). The pair of pressure receiving plates (42, 42) are plate-like members made of a hard resin material, and are disposed in the internal space (43) in a state parallel to each other.

    The second pressure sensitive tube (45) has the same configuration as the first pressure sensitive tube (35). That is, the second pressure-sensitive tube (45) constitutes a hollow second pressure-sensitive part on which the body movement of the driver (1) acts. The second pressure sensitive tube (45) is formed in an elongated hollow tube shape. The second pressure sensitive tube (45) is made of a flexible resin material (for example, vinyl chloride material). The tip (one end) of the second pressure-sensitive tube (45) is sealed with, for example, a stopper (not shown). You may form the small hole which connects the inside and the exterior of a 2nd pressure sensitive tube (45) to this stopper. The base end (other end) of the second pressure sensing tube (45) is connected to the signal processing unit (50).

    The 2nd pressure sensing tube (45) has the 2nd pressure sensing part main part (46) located in interior space (43). The second pressure sensing part main body (46) is disposed between the pair of pressure receiving plates (42, 42). Thereby, the substantial pressure-receiving area of the second pressure-sensitive part main body (46) is enlarged. The body movement of the driver (1) seated on the cushion (41) (fine movement derived from breathing and heartbeat) is transferred to the second pressure sensing tube (45) via the cushion (41) and the pressure receiving plate (42). Acting, the internal pressure of the second pressure sensing tube (45) changes accordingly.

<Signal processing unit>
The signal processing unit (50) includes a box-shaped casing (51). The casing (51) is disposed on the back side of the seat (11), for example (see FIG. 1). The casing (51) contains a first pressure sensor (52), a second pressure sensor (53), and a printed circuit board (not shown) (see FIG. 2). The printed circuit board is composed of electronic circuits including a central processing unit (CPU) and a storage device (memory, register, etc.). The printed circuit board includes a preprocessing unit (54), a noise cancellation unit (56), and a biological information acquisition unit (60) as blocks indicating functions executed on the electronic circuit.

    The first pressure sensor (52) and the second pressure sensor (53) are composed of, for example, a microphone. The first pressure sensor (52) is connected to the proximal end of the first pressure sensitive tube (35), and the second pressure sensor (53) is connected to the proximal end of the second pressure sensitive tube (45). . The first pressure sensor (52) outputs a first signal corresponding to the internal pressure of the first pressure sensitive tube (35). The second pressure sensor (53) outputs a second signal corresponding to the internal pressure of the second pressure sensing tube (45).

    In the biological information acquisition device (20), a first signal corresponding to the body movement acting on the first pressure sensing tube (35) is output from the first pressure sensor (52). At the same time, a second signal acting on the second pressure sensing tube (45) and corresponding to body movement is output from the second pressure sensor (53). That is, in the present embodiment, the first pressure sensing tube (35) and the first pressure sensor (52) constitute a first body motion detection unit (38) that detects a first signal corresponding to body motion. The second pressure sensing tube (45) and the second pressure sensor (53) constitute a second body motion detector (48) that detects a second signal corresponding to the body motion.

    The preprocessing unit (54) performs predetermined filter processing on the first signal and the second signal.

    The noise cancellation unit (56) generates a cancellation signal (error signal) in which noise (road noise or engine noise) of the automobile (10) is canceled based on the first signal and the second signal. The noise cancellation unit (56) has an adaptive filter (57) that performs adaptive processing based on the first signal and the second signal. The adaptive filter (57) performs an adaptive process that brings the waveform of the second signal closer to the first signal so that an error signal, which is the difference between the first signal and the second signal after the adaptive process, is reduced (details are given below). Will be described later).

    The biometric information acquisition unit (60) generates the first signal after being processed by the preprocessing unit (54), the second signal processed by the preprocessing unit (54), and the noise cancellation unit (56). Based on the canceled signal, the biological information of the driver (1) is acquired. The biological information acquisition unit (60) of the present embodiment detects heartbeat information (beat interval) of the driver (1). This heartbeat information is used, for example, for obtaining a stress index (LH / HF value) of the driver (1). The biological information acquisition unit (60) includes a storage unit (61), a pulsation extraction unit (62), an accuracy determination unit (63), and a data output unit (64).

    The storage unit (61) stores the first signal, the second signal, and the cancel signal every moment. The pulsation extraction unit (62) gradually calculates the pulsation interval of the driver (1) as biometric information based on each of these signals. The beat interval obtained here may also be stored in the storage unit (61) as appropriate.

    The accuracy determination unit (63) determines the signal having the highest accuracy of the pulsation interval among the three signals using the pulsation intervals based on the three types of signals obtained by the pulsation extraction unit (62). Specifically, the accuracy determination unit (63) creates a frequency distribution in a predetermined section in which time series data of the beat intervals is accumulated for each beat interval obtained from the three types of signals (FIG. 5). See). Then, the accuracy determination unit (63) calculates the pulsation interval having the largest number of appearance frequencies as the most frequent distribution in each of the three types of frequency distributions. Further, the accuracy determination unit (63) determines that the signal corresponding to the frequency distribution having the highest ratio of the mode distribution to the total frequency distribution among these frequency distributions is the signal with the highest accuracy. The accuracy determination unit (63) obtains the ratio of the most frequent distribution to the total frequency distribution based on the pulsation intervals based on the three types of signals, but instead based on the fluctuation values of the pulsation intervals. Thus, the ratio of the mode distribution to the total frequency distribution may be obtained.

    The biological information acquisition unit (60) obtains the final pulsation interval of the driver (1) using the signal thus determined by the accuracy determination unit (63). The data output unit (64) transmits the data of the final pulsation interval to the information terminal (70) (for example, a personal computer, a smartphone, a tablet, etc.). In the information terminal (70), for example, the stress state of the driver (1) is displayed based on the output beat interval. Accordingly, the driver (1) can appropriately check the stress-like body while riding in the automobile (10). In addition, the biological information including such stress information can be used for driving control of the automobile (10).

    In the present embodiment, the function relating to the biological information acquisition unit (60) is provided on the signal processing unit (50) side, but this function may be provided on the information terminal (70) side. In this case, the information terminal (70) constitutes a part of the biological information acquisition device (20).

<Details of noise canceling operation>
By the way, when the automobile (10) is traveling, the road noise and engine noise described above are generated. Such noise is also transmitted to the first pressure-sensitive tube (35) and the second pressure-sensitive tube (45). For this reason, not only a signal (biological signal) caused by the body movement of the driver (1) but also a signal (noise signal) caused by the noise is superimposed on the first signal and the second signal. Therefore, in the present embodiment, the noise signal can be removed by the noise cancellation unit (56). This operation will be described with reference to FIGS.

    The first signal and the second signal are input to the noise cancellation unit (56). In the noise cancellation unit (56), the adaptive processing of the second signal is performed by the adaptive filter (57) so that the first signal is the main signal and the noise signal is removed from the first signal. Here, the adaptive filter (57) is a known digital filter that self-adapts its transfer function in accordance with an optimization algorithm.

    As shown in FIG. 6, first, the second signal (x) input to the noise canceling unit (56) is subjected to filter processing of a predetermined filter coefficient by the adaptive filter (57), and the output (y) is obtained. can get. On the other hand, a predetermined time delay is given to the first signal (c) input to the noise cancellation unit (56), and an output (d) is obtained. Thereby, the convergence property and causality of the adaptive filter (57) can be satisfied. The adaptive filter (57) gradually updates the filter coefficients so that a cancel signal (e) (also referred to as an error signal or an error signal) that is the difference between the output (y) and the output (d) becomes small. At this time, a known LMS (Least Mean Square) algorithm is used as an algorithm for updating the filter coefficient.

    As described above, the adaptive filter (57) causes the second signal (e) so that the cancellation signal (e), which is the difference between the first signal (d) and the second signal (y) after the adaptive processing, becomes small. x) Adaptive processing is performed. As a result, the noise signal described above is removed from the cancel signal (e). This point will be described in more detail with reference to FIG.

    As schematically shown in FIG. 7, the first signal and the second signal have waveforms in which a biological signal resulting from the body movement of the driver (1) and a noise signal are superimposed. Here, the vibration level of noise is extremely large as compared with the vibration level of fine movement derived from heartbeat or respiration. For this reason, in the first signal and the second signal, the level of the noise signal is relatively larger than that of the biological signal. Therefore, in the adaptive processing, a noise signal having a high level is canceled, while a biological signal having a low level is hardly removed. As a result, the biological signal is likely to remain in the cancel signal.

    In addition, the first pressure sensing tube (35) and the second pressure sensing tube (45) are strictly at different positions. For this reason, for example, the movement of the heartbeat of the driver (1) is transmitted to the first pressure sensitive tube (35) and the second pressure sensitive tube (45) at different timings. Therefore, as shown in FIG. 7, the phase of the component of the biological signal of the first signal and the component of the biological signal of the second signal tend to slightly shift. On the other hand, road noise and engine noise act on the driver (1) at almost the same timing throughout the body. For this reason, even if the installation location of a 1st pressure sensing tube (35) and a 2nd pressure sensing tube (45) differs, the phase of the noise signal of a 1st signal and a 2nd signal hardly changes. Therefore, in the adaptive processing, a noise signal having the same phase between two signals is easily canceled, but biological signals having different phases are not easily canceled. For this reason, the biological signal is likely to remain in the cancel signal. Therefore, by performing the adaptive process, it is possible to obtain a cancel signal in which the noise signal is removed and the biological signal appears sufficiently.

<Details of judgment operation>
As described above, the accuracy determination unit (63) includes the cancel signal thus obtained, the first signal corresponding to the first pressure-sensitive tube (35) attached to the driver (1), and the seat. The most accurate signal is determined from the second signal corresponding to the second pressure-sensitive tube (45) provided in (11).

    For example, since road noise and engine noise increase during traveling of the automobile (10), the noise signal derived from noise tends to increase in the first signal and the second signal. On the other hand, in the cancel signal, the noise signal is removed as described above. For this reason, in such a situation, the accuracy of the cancel signal (mode distribution ratio) is higher than the accuracy of the first signal and the second signal (mode distribution ratio), and the heartbeat is based on the cancel signal. Information is required.

    On the other hand, for example, when the automobile (10) is stopped, road noise and engine noise are reduced, so that the noise signal superimposed on the first signal and the second signal is reduced. In this case, the accuracy of the first signal or the second signal is higher than the accuracy of the cancel signal, and the heart rate information may be obtained based on the first signal or the second signal.

    In addition, for example, in a transient state where the automobile (10) is accelerated rapidly, the cancellation of the noise signal by the adaptive processing may not be in time, and the accuracy of the heartbeat information obtained from the cancellation signal may be reduced. Even in such a case, the accuracy of the first signal or the second signal may be higher than the accuracy of the cancel signal, and the heart rate information may be obtained based on the first signal or the second signal.

    Due to the change in the posture and seating position of the driver (1), the accuracy of the second signal corresponding to the second pressure sensing tube (45) in the seat (11) may be lowered. In such a case, the accuracy of the first signal may be higher than the accuracy of the second signal, and heart rate information may be obtained based on the first signal. This is because the first pressure-sensitive tube (35) is attached to the driver (1) and thus is not significantly affected by the posture of the driver (1) and the seating position.

    If the noise is reduced when the car (10) is stopped, the respiratory component in the detected signal may be noticeable. This is because the level of the respiratory component is the second largest after the noise level when compared with the noise, respiratory component, and heart rate component. Therefore, it is difficult to extract the heart rate component due to the influence of the respiratory component, and the accuracy of the heart rate information may be reduced. In such a situation, the accuracy of the second signal may be higher than the accuracy of the first signal, and heart rate information may be obtained based on the second signal. The second pressure sensing tube (45) in the seat (11) is less likely to propagate microtremors derived from breathing than the wearable first pressure sensing tube (35), and the breathing component is less likely to be superimposed on the second signal. Because.

    As described above, in the present embodiment, the accuracy of the first signal, the second signal, and the cancel signal changes in various situations as described above. In contrast, the biological information acquisition unit (60) determines a signal with the highest accuracy according to the change in accuracy, and obtains heartbeat information based on the signal after the determination. As a result, in this embodiment, even if there is a situation change as described above, heart rate information can always be acquired with high accuracy.

-Effect of the embodiment-
In the present embodiment, adaptive processing is performed based on signals detected by the two pressure sensitive tubes (35, 45), and biological information is acquired based on a cancel signal after the adaptive processing. As a result, noise such as road noise and engine noise can be canceled, and detection accuracy of biological information can be improved. In this embodiment, noise can be canceled by using two pressure-sensitive tubes (35, 45) having a relatively simple configuration, and an acceleration sensor or the like is not necessary. Therefore, simplification and cost reduction of the biological information acquisition device (20) can be achieved.

    In this embodiment, it adapts using the 1st signal according to the wearing type 1st pressure sensing tube (35), and the 2nd signal according to the 2nd pressure sensing tube (45) provided in the seat (11). Processing is in progress. Since the first pressure-sensitive tube (35) and the second pressure-sensitive tube (45) have different ways of transmitting fine motion derived from the heartbeat, the phase of the biological signal in both signals also changes. As a result, it is possible to prevent the biological signal itself from being canceled in the adaptive processing, and it is possible to reliably leave the biological signal in the cancel signal (see FIG. 7).

    In the adaptive processing, the first signal that is the main signal before noise is removed corresponds to the wearable first pressure-sensitive tube (35). For this reason, even if a driver | operator's (1) attitude | position and seating position change, a biological signal can be reliably superimposed on a 1st signal. As a result, it is possible to improve the accuracy of the biological information associated with the adaptive process.

    The biological information acquisition unit (60) acquires heart rate information using a signal having the highest accuracy among the cancel signal, the first signal, and the second signal. For this reason, it can prevent reliably that the precision of heart rate information falls due to the change of the situation of a vehicle (10) or a driver (1), and can improve the reliability of a living body information acquisition device (20). .

-Modification-
In the biological information acquisition device (20) of the above embodiment, the first pressure-sensitive tube (35) and the second pressure-sensitive tube (45) may be configured as in the following modifications.

<Modification 1>
In the first modification shown in FIG. 8, the first pressure sensing tube (35) is provided on the handle (14) of the driving seat (11). The second pressure-sensitive tube (45) is embedded in, for example, the seat (12) of the seat (11). Therefore, when the driver (1) grasps the handle (14), the body movement of the driver (1) acts on the first pressure sensing tube (35) through the hand. Further, the body movement of the driver (1) is transmitted to the inside of the seat (12) and acts on the second pressure sensing tube (45).

    Also in the first modified example, a difference occurs in the way body motion is transmitted between the first pressure-sensitive tube (35) and the second pressure-sensitive tube (45), and therefore the waveform of the biological signal superimposed on the first signal and the second signal. There is also a difference. As a result, it is possible to reliably prevent the biological signal from being canceled by the adaptive processing.

    The first signal, which is the main signal of the adaptive processing, corresponds to the first pressure sensing tube (35) in the handle (14). For this reason, the biological signal is surely superimposed on the first signal. As a result, it is possible to improve the accuracy of the biological information associated with the adaptive process.

<Modification 2>
In the second modification shown in FIG. 9, the first pressure-sensitive tube (35) is embedded in the seat (12) of the seat (11). The second pressure sensitive tube (45) is embedded in the backrest (13) of the seat (11). That is, the first pressure sensing tube (35) and the second pressure sensing tube (45) are provided at different locations in the same seat (11) on which the driver (1) is seated. The first pressure-sensitive tube (35) and the second pressure-sensitive tube (45) are greatly different in relative position from the driver (1). For this reason, a large shift also occurs in the waveform superimposed on the first signal and the second signal. As a result, it is possible to reliably prevent the biological signal from being canceled by the adaptive processing.

    In the second modification, the driver (1) does not notice the presence of the first pressure sensing tube (35) and the second pressure sensing tube (45), and the driver (1) can be prevented from feeling uncomfortable. Therefore, the comfort of the driver (1) can be improved.

<Modification 3>
In Modification 3 shown in FIG. 10, the first pressure-sensitive tube (35) is provided on the seat belt (15). Specifically, the first pressure-sensitive tube (35) is provided on, for example, a chest belt portion (16) that is attached to the chest of the driver (1) in the seat belt (15). Thereby, the first pressure-sensitive tube (35) is attached to the chest of the driver (1). The second pressure-sensitive tube (45) is embedded in, for example, the seat (12) of the seat (11).

    The first pressure-sensitive tube (35) and the second pressure-sensitive tube (45) are greatly different in relative position from the driver (1). For this reason, a large shift also occurs in the waveform superimposed on the first signal and the second signal. As a result, it is possible to reliably prevent the biological signal from being canceled by the adaptive processing.

    The first signal, which is the main signal of the adaptive processing, corresponds to the wearable first pressure sensing tube (35). For this reason, even if a driver | operator's (1) attitude | position and seating position change, a biological signal can be reliably superimposed on a 1st signal. As a result, it is possible to improve the accuracy of the biological information associated with the adaptive process.

    For example, the first pressure sensing part (35) may be provided in the waist belt part (17) of the seat belt (15).

<Other embodiments>
The biological information acquisition device (20) may extract a respiratory component from a biological signal and acquire respiratory information as biological information.

    The first body motion detector (38) of the above-described embodiment and each modification is configured to detect a biological signal by the first pressure-sensitive tube (35) and the first pressure sensor (52). The second body motion detector (48) is configured to detect a biological signal by the second pressure sensing tube (45) and the second pressure sensor (53). However, the first body motion detection unit (38) and the second body motion detection unit (48) may be piezoelectric elements (piezoelectric sensors) that convert body motion acting on the piezoelectric body, which is a pressure-sensitive unit, into signals. Good. Also in this case, it is possible to cancel noise by performing adaptive processing based on the first signal detected by the first piezoelectric element and the second signal detected by the second piezoelectric element.

    Further, instead of the tube-shaped first pressure-sensitive tube (35) and the second pressure-sensitive tube (45), a hollow bag-shaped pressure-sensitive portion may be used.

    The arrangement of the pressure-sensitive parts (35, 45) (pressure-sensitive tubes and piezoelectric bodies) is not limited to the above-described embodiments and modifications, and the arrangement of the first pressure-sensitive part (35) and the second pressure-sensitive part (45). May be reversed, or the arrangement of the pressure-sensitive parts (35, 45) described so far may be combined in any pattern.

    The first pressure sensing part (35) and the second pressure sensing part (45) are attached to the living body (1) via an attachment other than the belt (2) and the seat belt (15) described above. Also good. Further, the first pressure sensitive part (35) and the second pressure sensitive part (45) may be attached to the living body (1) so as to directly touch the living body (1).

    The biological information acquisition unit (60) determines the most accurate signal from among the first signal, the second signal, and the cancel signal. However, the biological information acquisition unit (60) may determine a highly accurate signal among the first signal and the cancel signal, or determine a highly accurate signal among the second signal and the cancel signal. It may be. Further, the biometric information acquisition unit (60) may obtain the biometric information using only the cancel signal.

    The vehicle (10) to which the biological information acquisition device (20) is applied is not necessarily limited to an automobile, and may be another transfer body such as a railroad.

    The living body targeted by the biological information acquisition device (20) is not limited to the driver (1). For example, the target living body may be a passenger sitting in a passenger seat or another seat, or a newborn or infant sitting in a child seat. In addition, the living body targeted by the biological information acquisition device (20) is an animal (for example, a pet such as a cat or a dog) on the seat (11) of the vehicle (10) or an animal (for example, an animal carried by the vehicle (10)). Horse etc.).

    As described above, the present invention is useful for a biological information acquisition apparatus.

10 Vehicle 11 Seat 14 Handle 35 First pressure sensing tube (first pressure sensing part)
38 1st body motion detection part 45 2nd pressure sensing tube (2nd pressure sensing part)
48 Second body motion detection unit 57 Adaptive filter 60 Biological information acquisition unit 63 Accuracy determination unit (determination unit)

Claims (10)

A first pressure sensing part (35) on which the body movement of the living body (1) on the vehicle (10) acts, and outputs a first signal corresponding to the body movement acting on the first pressure sensing part (35) A first body motion detector (38) that
A second signal corresponding to the body motion acting on the second pressure sensing portion (45), having a second pressure sensing portion (45) on which the body motion of the living body (1) on the vehicle (10) acts. A second body motion detector (48) that outputs
An adaptive filter (57) for processing the second signal so that an error signal, which is a difference between the first signal and the second signal after the adaptive processing, is reduced;
A biological information acquisition device comprising: a biological information acquisition unit (60) that obtains biological information of the biological body (1) based on the error signal. In claim 1,
One of the first pressure sensing part (35) and the second pressure sensing part (45) is attached to the living body (1),
The biological information acquisition apparatus, wherein the other of the first pressure sensing part (35) and the second pressure sensing part (45) is provided in a seat (11) of the vehicle (10). In claim 1,
One of the first pressure sensing part (35) and the second pressure sensing part (45) is provided on the handle (14) of the vehicle (10),
The biological information acquisition apparatus, wherein the other of the first pressure sensing part (35) and the second pressure sensing part (45) is provided in a seat (11) of the vehicle (10). In claim 1,
The biometric information acquisition apparatus characterized in that both the first pressure sensing part (35) and the second pressure sensing part (45) are provided in a seat (11) of the vehicle (10). In claim 1 or 2,
The biological information acquisition device according to claim 1, wherein the first pressure sensing unit (35) is attached to the living body (1). In claim 1 or 3,
The biological information acquisition apparatus according to claim 1, wherein the first pressure sensing part (35) is provided on a handle (14) of the vehicle (10). In any one of Claims 1 thru | or 6,
The biological information acquisition unit (60) includes a determination unit (63) that determines a signal having the highest accuracy of biological information among the error signal and at least one of the first signal and the second signal. A biometric information acquisition apparatus for obtaining biometric information of the living body (1) using a highly accurate signal determined by the unit (63). In claim 7,
The biometric information acquisition apparatus, wherein the determination unit (63) determines a signal with high accuracy of biometric information from the three signals of the error signal, the first signal, and the second signal. In claim 7 or 8,
The determination unit (63) includes the error signal and a signal corresponding to the pressure sensing unit (35, 45) provided in the seat (11) of the vehicle (10) among the first signal and the second signal. A biological information acquisition apparatus characterized by determining a signal with high accuracy of biological information from the inside and obtaining heart rate information of the biological body (1) using the signal with high accuracy. In any one of Claims 7 thru | or 9,
The determination unit (63) obtains a frequency distribution of an index indicating the biological information of at least one of the error signal and the first signal and the second signal, and calculates a mode distribution of all frequencies of the frequency distribution. A biological information acquiring apparatus, wherein a signal having the highest ratio is determined as a signal with high accuracy.

Images