Biometric information detection device and vehicle equipped therewith

Abstract

The present invention realizes a biological information detection device capable of acquiring highly accurate biological information. This invention is provided with: a radio wave sensor (2) for detecting the body surface displacement of a human body; a first vibration sensor (31) that is installed, with the radio wave sensor (2), at a position set away from a holding surface holding the human body; a second vibration sensor (32) installed at a position closer to the holding surface than is the first vibration sensor; a signal processing unit (6) for generating a biological signal for the human body on the basis of the body surface displacement acquired by the radio wave sensor (2), a first vibration component acquired by the first vibration sensor (31), and a second vibration component acquired by the second vibration sensor (32).

Description

Technical Field

[0001] The present invention relates to a biological information detection device and a vehicle equipped with the same.

Background Art

[0002] There is disclosed an occupant state detection system that detects occupants in the driver's seat, passenger seat, and rear seat of a vehicle, and in the driver's seat and the like, not only detects occupants but also acquires biological information (for example, Patent Document 1). In the occupant state detection system of Patent Document 1, a radio wave sensor mounted in the vehicle transmits radio waves, receives the reflected waves thereof, and detects the distance from the reflecting object. The occupant state detection system checks whether the detected distance is fluctuating by calculating the distance fluctuation from the distances from the reflecting objects detected over time. As a result, if there is no distance fluctuation or the distance fluctuation is below a certain detection value, it is determined that there is no person (occupant) in the vehicle. Further, if the distance is fluctuating or the distance fluctuation is above a certain value, it is determined that a person is present in the vehicle. However, when vibration of the radio wave sensor or vibration of an object such as a person occurs, the radio wave sensor signal output by the radio wave sensor includes a vibration component due to the vibration. When the vibration component is included in the radio wave sensor signal, the detection accuracy of the signal processing system may decrease.

[0003] For example, there is disclosed a signal processing system and a sensor system that can attenuate the vibration component from the radio wave sensor signal and improve the detection accuracy of the state of an object (for example, Patent Document 2). The signal processing system of Patent Document 2 includes a first receiving unit, a second receiving unit, and a signal processing unit. The first receiving unit receives a radio wave sensor signal from a radio wave sensor that receives radio waves reflected by an object. The second receiving unit receives a vibration sensor signal corresponding to the vibration of at least one of the radio wave sensor and the object from a vibration sensor. The signal processing unit detects information regarding the state of the object based on the radio wave sensor signal and the vibration sensor signal.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-202921 [Patent Document 2] Japanese Patent Publication No. 2021-71326 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the signal processing system and sensor system disclosed in Patent Document 1, since the radio wave sensor (radar) is a sensor that measures distance, the vibrations mixed into the measurement values ​​are vibrations of the human body relative to the radio wave sensor installation position. Because the human body is on an elastic material such as urethane, it vibrates in a different way than the vibrations of the vehicle (e.g., automobile) itself. In other words, the radar measurement values ​​are affected not only by the biological information of the object being measured (human body) but also by the movement of the human body accompanying the operation of the vehicle. In the above-mentioned conventional technology, the influence of the movement of the human body accompanying the operation of the vehicle can be suppressed by using the measurement values ​​of the vibration sensor, but the measurement values ​​of the vibration sensor include vibrations originating from the vehicle body vibration in addition to the movement of the human body accompanying the operation of the vehicle. For this reason, the accuracy of the biological information of the human body, which is the object being measured, may decrease.

[0006] This disclosure is made in view of the above, and aims to realize a biometric information detection device capable of acquiring highly accurate biometric information, and a vehicle equipped therewith. [Means for solving the problem]

[0007] A biological information detection device according to one aspect of this disclosure includes: a radio wave sensor for detecting surface displacement of a human body; a first vibration sensor installed together with the radio wave sensor at a position away from a holding surface that holds the human body; a second vibration sensor installed closer to the holding surface than the first vibration sensor; and a signal processing unit that generates a biological signal of the human body based on the surface displacement acquired by the radio wave sensor, a first vibration component acquired by the first vibration sensor, and a second vibration component acquired by the second vibration sensor.

[0008] In this configuration, biosignals of the human body are generated based on body surface displacement acquired by a radio wave sensor, a first vibration component acquired by a first vibration sensor, and a second vibration component acquired by a second vibration sensor. This makes it possible to suppress both the influence of the subject's body movement and the influence of vibration components originating from the body vibration of a vehicle (e.g., an automobile).

[0009] One aspect of the present disclosure is a vehicle equipped with the biometric information detection device described above.

[0010] This configuration makes it possible to realize a vehicle equipped with a biometric information detection device that can acquire highly accurate biological information by suppressing both the influence of the subject's body movement components and the influence of vibration components originating from the vehicle's body vibration. [Effects of the Invention]

[0011] According to this disclosure, it is possible to realize a biometric information detection device capable of acquiring highly accurate biometric information, and a vehicle equipped therewith. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a side view showing an example of application when the biometric information detection device according to Embodiment 1 is applied as a driver monitoring system for a vehicle. [Figure 2] Figure 2 is a block diagram showing the schematic configuration of a biological information detection device according to Embodiment 1. [Figure 3A] Figure 3A shows an example of the relationship between body surface displacement obtained by a radio wave sensor and the first vibration component obtained by a first vibration sensor. [Figure 3B] Figure 3B shows an example of the relationship between the first vibration component acquired by the first vibration sensor and the second vibration component acquired by the second vibration sensor. [Figure 3C] Figure 3C shows an example of the relationship between body surface displacement acquired by a radio wave sensor and estimated vibration components generated by the vibration estimation unit. [Figure 4]FIG. 4 is a side view showing an application example when the biological information detection device according to Embodiment 2 is applied as a driver monitoring system for a vehicle. [Figure 5] FIG. 5 is a block diagram showing a schematic configuration of the biological information detection device according to Embodiment 2. [Figure 6] FIG. 6 is a diagram for explaining an example of the coordinate rotation method according to Embodiment 2. [Figure 7] FIG. 7 is a side view showing an application example when the biological information detection device according to Embodiment 3 is applied as a driver monitoring system for a vehicle. [Figure 8] FIG. 8 is a block diagram showing a schematic configuration of the biological information detection device according to Embodiment 3.

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, a biological information detection device according to an embodiment and a vehicle equipped with the same will be described in detail based on the drawings. Note that the present disclosure is not limited by this embodiment.

[0014] (Embodiment 1) FIG. 1 is a side view showing an application example when the biological information detection device according to Embodiment 1 is applied as a driver monitoring system for a vehicle. The biological information detection device 1 is applied, for example, to the driver monitoring system (DMS: Driver Monitoring System) shown in FIG. 1 and is installed inside the seat 5 on which the driver who becomes the subject 4 sits in the vehicle. As shown in FIG. 1, the biological information detection device 1 includes a radio wave sensor 2, a first vibration sensor 31, and a second vibration sensor 32.

[0015] ​​​​The radio wave sensor 2 is, for example, a radar device provided on a dielectric substrate 20. The radio wave sensor 2 is installed on the back side of the sheet 5. The radio wave sensor 2 detects the displacement of the distance to the body surface of the electromagnetic wave irradiation location on the subject 4 (body surface displacement).

[0017] Examples of the material of the dielectric substrate 20 include a low-temperature co-fired ceramic multilayer substrate (LTCC (Low Temperature Co-fired Ceramics) multilayer substrate), a multilayer resin substrate formed by laminating a plurality of resin layers composed of resins such as epoxy and polyimide, a multilayer resin substrate formed by laminating a plurality of resin layers composed of a liquid crystal polymer (Liquid Crystal Polymer: LCP) having a lower dielectric constant, a multilayer resin substrate formed by laminating a plurality of resin layers composed of a fluorine-based resin, a ceramic multilayer substrate (excluding a low-temperature fired ceramic multilayer substrate), and the like.

[0018] On the surface of the dielectric substrate 20 facing the human body surface of the subject 4, a transmission / reception antenna (not shown) of the radio wave sensor 2 is provided. The radio wave sensor 2 irradiates electromagnetic waves from the transmission / reception antenna provided on the dielectric substrate 20 to the human body surface of the subject 4, and receives the electromagnetic waves reflected from the human body surface of the subject 4 by the transmission / reception antenna. The modulation method of the electromagnetic waves by the radio wave sensor 2 is performed by a Doppler method, an FMCW (Frequency Modulated Continuous Wave radar) method, a pulse modulation method, or the like. As the modulation method of the electromagnetic waves by the radio wave sensor 2, any method may be used as long as it can measure the displacement of the distance to the human body surface of the subject 4, which is the target object, and is not limited to the above modulation methods. Hereinafter, the surface of the dielectric substrate 20 where the transmission / reception antenna is provided is also referred to as the "antenna surface".

[0019] The first vibration sensor 31 and the second vibration sensor 32 are, for example, acceleration sensors. The first vibration sensor 31 is installed on the back side of the seat 5 together with the radio wave sensor 2. Specifically, the first vibration sensor 31 is installed on the dielectric substrate 20 on which the radio wave sensor 2 is provided, and is housed in the same housing 3 as the radio wave sensor 2. The second vibration sensor 32 is installed on the front side of the seat 5. Specifically, the second vibration sensor 32 is installed on the back side of the surface material 5b of the seat 5 that comes into contact with the human body of the subject 4, such as the back and seat of the seat 5, that is, on the surface material 5b side of the internal material 5a of the seat 5. In other words, the first vibration sensor 31 is installed at a position away from the holding surface that holds the human body (for example, the back side of the surface material 5b of the seat 5), together with the radio wave sensor 2, and the second vibration sensor 32 is installed at a position closer to the holding surface that holds the human body than the first vibration sensor 31.

[0020] In this disclosure, the biometric information detection device 1 detects biometric information (vital signs) such as heart rate, heart rate variability, respiratory rate, and respiratory depth of a subject 4 driving a vehicle, based on body surface displacement (displacement of the distance to the subject's body surface) acquired by the radio wave sensor 2 and vibration displacement acquired by the first vibration sensor 31 and the second vibration sensor 32. In this embodiment, the direction A of the body surface displacement acquired by the radio wave sensor 2, the vibration detection direction (acceleration detection direction) B of the first vibration sensor 31, and the vibration detection direction C of the second vibration sensor 32 are assumed to be in the same direction.

[0021] Figure 2 is a block diagram showing the schematic configuration of a biometric information detection device according to Embodiment 1. The biometric information detection device 1 according to Embodiment 1 includes a radio wave sensor 2, a first vibration sensor 31, and a second vibration sensor 32, as well as a radio wave sensor signal receiving unit 41, a first vibration sensor signal receiving unit 51, a second vibration sensor signal receiving unit 52, and a signal processing unit 6.

[0022] The radio wave sensor signal receiving unit 41, the first vibration sensor signal receiving unit 51, the second vibration sensor signal receiving unit 52, and the signal processing unit 6 are configured as modules provided, for example, on the back surface of the antenna surface of the dielectric substrate 20. Each of these units is realized by software control processing of a microcomputer, by hardware configuration of an electronic circuit, or by both software control processing of the microcomputer and hardware configuration of an electronic circuit. Specifically, the signal processing unit 6 is configured, for example, as an IC (integrated circuit).

[0023] The radio wave sensor 2 generates, for example, a continuous wave (CW) signal as the transmitted wave and transmits it toward the human body of the subject 4. For example, in a configuration in which the Doppler method is used as the modulation method for electromagnetic waves by the radio wave sensor 2, the radio wave sensor 2 outputs a radio wave sensor signal to the radio wave sensor signal receiving unit 41 that corresponds to the difference in frequency between the transmitted and received transmitted wave and the reflected wave. The transmitted wave may be, for example, a millimeter wave or a microwave. In this embodiment, an example is described in which the radio wave sensor 2 irradiates electromagnetic waves (for example, millimeter waves) as the transmitted wave, but the transmitted wave broadly includes sound waves, light waves, etc.

[0024] The radio wave sensor signal receiving unit 41 receives the radio wave sensor signal from the radio wave sensor 2, amplifies the radio wave sensor signal as appropriate, converts it into a digital signal using an AD converter, converts it into a displacement signal, and outputs it to the signal processing unit 6 as a body surface displacement signal.

[0025] The first vibration sensor 31 outputs a first vibration sensor signal corresponding to the detected vibration to the first vibration sensor signal receiving unit 51.

[0026] The first vibration sensor signal receiving unit 51 receives the first vibration sensor signal from the first vibration sensor 31, amplifies the first vibration sensor signal as appropriate, converts it into a digital signal using an AD converter, and outputs it to the signal processing unit 6.

[0027] The second vibration sensor 32 outputs a second vibration sensor signal corresponding to the detected vibration to the second vibration sensor signal receiving unit 52.

[0028] The second vibration sensor signal receiving unit 52 receives the second vibration sensor signal from the second vibration sensor 32, amplifies the second vibration sensor signal as appropriate, converts it into a digital signal using an AD converter, and outputs it to the signal processing unit 6.

[0029] The signal processing unit 6 includes a vibration estimation unit 7 and a vibration removal unit 8.

[0030] The vibration estimation unit 7 includes a first displacement conversion unit 71 and a second displacement conversion unit 72. The first displacement conversion unit 71 converts the first vibration sensor signal output from the first vibration sensor signal receiving unit 51 into a first vibration signal. The first vibration signal is the first vibration component acquired by the first vibration sensor 31. The second displacement conversion unit 72 converts the second vibration sensor signal output from the second vibration sensor signal receiving unit 52 into a second vibration signal. The second vibration signal is the second vibration component acquired by the second vibration sensor 32. The vibration estimation unit 7 outputs the estimated vibration component, obtained by subtracting the first vibration component from the second vibration component, as the estimated vibration signal to the vibration removal unit 8.

[0031] The vibration removal unit 8 separates the estimated vibration signal, which is the result of the vibration estimation unit 7's calculations, from the body surface displacement signal output from the radio wave sensor signal receiving unit 41, and generates a biosignal of the subject 4's human body. This provides a biosignal from which unwanted vibration components have been separated.

[0032] Here, the concept of high-precision acquisition of biological information in the biological information detection device 1 according to this disclosure will be explained. Figure 3A is a diagram showing an example of the relationship between body surface displacement acquired by the radio wave sensor and the first vibration component acquired by the first vibration sensor. Figure 3B is a diagram showing an example of the relationship between the first vibration component acquired by the first vibration sensor and the second vibration component acquired by the second vibration sensor. Figure 3C is a diagram showing an example of the relationship between body surface displacement acquired by the radio wave sensor and the estimated vibration component generated by the vibration estimation unit. In Figures 3A, 3B, and 3C, the horizontal axis represents the passage of time, and the vertical axis represents displacement. Also, in Figures 3A, 3B, and 3C, the solid line represents the body surface displacement acquired by the radio wave sensor 2, the dashed line represents the second vibration component acquired by the second vibration sensor 32, the dashed line represents the first vibration component acquired by the first vibration sensor 31, and the dashed line represents the estimated vibration component generated by the vibration estimation unit 7. Note that in Figures 3A, 3B, and 3C, the DC component of each component is omitted.

[0033] The body surface displacement (solid line in Figure 3A) acquired by the radio wave sensor 2 includes not only a displacement component (hereinafter also referred to as the "biological signal") caused by the biological information of the subject 4, who is the target of detection by the biological information detection device 1 according to this disclosure, but also a vibration component (hereinafter also referred to as the "body movement component") associated with the body movement of the subject 4 (the movement of the subject 4's body accompanying the driving of the vehicle).

[0034] The vibration removal unit 8 generates the subject's biological signal by separating the body motion component from the body surface displacement acquired by the radio wave sensor 2 using an adaptive filter, which will be described later (hereinafter also referred to as "adaptive processing").

[0035] The second vibration component acquired by the second vibration sensor 32 (dashed line in Figure 3B) includes not only the body movement component of subject 4, but also vibration components originating from the movement of the vehicle (e.g., an automobile) body and vibrations from the engine, etc. (hereinafter also referred to as "vehicle body vibration"). On the other hand, the first vibration component acquired by the first vibration sensor 31 (dotted line in Figures 3A and 3B) contains many vibration components originating from the vehicle body vibration.

[0036] In this disclosure, as described above, the vibration estimation unit 7 generates an estimated vibration component by subtracting the first vibration component obtained by the first vibration sensor 31 from the second vibration component obtained by the second vibration sensor 32. This results in an estimated vibration component that suppresses the influence of vibration components originating from the vehicle body vibration.

[0037] In this way, by subtracting the first vibration component (dashed line in Figure 3B), which is acquired by the first vibration sensor 31 and contains a large amount of vibration components originating from the vehicle's body vibration, from the second vibration component (dashed line in Figure 3B), which is acquired by the second vibration sensor 32 and contains vibration components originating from the vehicle's body vibration in addition to the body movement component of the subject 4, a vibration signal (double dashed line in Figure 3C) with the body movement component of the subject 4 as the main component is generated. By performing adaptive processing using this vibration signal, highly accurate biological information can be obtained.

[0038] Specifically, the vibration removal unit 8 uses an adaptive filter that applies algorithms such as LMS (Least Mean Square) and RLS (Recursive Least Square) to separate the estimated vibration signal, which is the result of the vibration estimation unit 7's calculations, from the body surface displacement signal output from the radio wave sensor signal receiving unit 41. This results in a biosignal from which unwanted vibration components have been separated.

[0039] Furthermore, the method for separating vibration sensor signals from radio wave sensor signals is not limited to this. For example, it may also involve using blind source separation (BBS) such as independent component analysis (ICA), independent vector analysis (IVA), or independent low-rank matrix analysis (ILRMA), or it may also involve using mode decomposition such as ensemble empirical mode decomposition (EEMD) or multivariate variational mode decomposition (MVMD). This disclosure is not limited by the method for separating vibration sensor signals from radio wave sensor signals.

[0040] In the configuration shown in Figure 2, the filter 8a has its filter coefficient Wo variably set by the adaptive processing unit 8b. The filter 8a generates a vibration estimation signal by convolving the vibration sensor signal with the filter coefficient Wo. The vibration estimation signal corresponds to the estimated result of the vibration component contained in the body surface displacement signal acquired by the radio wave sensor 2. The vibration removal unit 8 generates a filtered signal as a biological signal by subtracting the vibration estimation signal from the body surface displacement signal.

[0041] As described above, the body surface displacement signal acquired by the radio wave sensor 2 includes not only the biosignals of the subject 4's body but also the body movement component of subject 4 (the movement component of subject 4's body associated with driving the vehicle). The adaptive processing unit 8b sets the filter coefficient Wo so that the correlation between the vibration sensor signal and the filtered signal (biosignal) is minimized. This makes it possible to obtain a biosignal (filtered signal) from the radio wave sensor signal with the body movement component of subject 4 attenuated.

[0042] By using the biosignals obtained as described above to acquire the vital signs of subject 4, it is possible to suppress both the influence of subject 4's body movement components and the influence of vibration components originating from the vehicle's body vibrations, thereby obtaining highly accurate biosignal information. A detailed explanation of the method for acquiring vital signs is omitted here, but this disclosure is not limited by the method for acquiring vital signs.

[0043] According to the bio-information detection device 1 of this embodiment 1, the first vibration component, which is acquired by the first vibration sensor 31 and contains a large amount of vibration components originating from the vehicle's body vibration, is subtracted from the second vibration component, which is acquired by the second vibration sensor 32 and includes vibration components originating from the vehicle's body vibration in addition to the body movement component of the subject 4. This results in an estimated vibration component that suppresses the influence of vibration components originating from the vehicle's body vibration. The estimated vibration signal is then separated from the body surface displacement signal acquired by the radio wave sensor 2, and a bio-signal of the human body with the body movement component of the subject 4 suppressed is generated. This makes it possible to acquire highly accurate bio-information.

[0044] (Embodiment 2) Figure 4 is a side view showing an example of application when the biometric information detection device according to Embodiment 2 is applied as a driver monitoring system for a vehicle. Figure 5 is a block diagram showing the schematic configuration of the biometric information detection device according to Embodiment 2. In Figure 4, the housing 3 is omitted.

[0045] In the biometric information detection device 1a according to Embodiment 2, the first vibration sensor 31a and the second vibration sensor 32a are 3-axis acceleration sensors. In this embodiment, the direction A of displacement detected by the radio wave sensor 2 is different from the vibration detection direction (acceleration detection direction) B of the first vibration sensor 31 and the vibration detection direction C of the second vibration sensor 32.

[0046] The first vibration sensor 31a outputs a first vibration sensor signal corresponding to the detected vibration in the three axes to the first vibration sensor signal receiving unit 51a.

[0047] The first vibration sensor signal receiving unit 51a receives the first vibration sensor signal corresponding to the vibration in the three axes from the first vibration sensor 31a, amplifies the first vibration sensor signal as appropriate, converts it into a digital signal using an AD converter, and outputs it to the signal processing unit 6a.

[0048] The second vibration sensor 32a outputs a second vibration sensor signal corresponding to the detected vibration in the three axes to the second vibration sensor signal receiving unit 52a.

[0049] The second vibration sensor signal receiving unit 52a receives the second vibration sensor signal corresponding to the vibration in the three axes from the second vibration sensor 32a, amplifies the second vibration sensor signal as appropriate, converts it into a digital signal using an AD converter, and outputs it to the signal processing unit 6a.

[0050] The vibration estimation unit 7a of the signal processing unit 6a according to Embodiment 2 includes a first vibration displacement rotation unit 73 that rotates the direction of vibration detected by the first vibration sensor 31a, and a second vibration displacement rotation unit 74 that rotates the direction of vibration detected by the second vibration sensor 32a.

[0051] When the displacement direction (X,Y,Z) of the body surface displacement signal acquired by the radio wave sensor 2 is used as a reference, the three-axis vibration (x',y',z') detected by the first vibration sensor 31a or the second vibration sensor 32a can be converted to the vibration direction (x,y,z) of the radio wave sensor 2 using, for example, the coordinate rotation formula shown in equation (1) below. In (1) below, α represents the rotation angle in the X-axis direction, β represents the rotation angle in the Y-axis direction, and γ represents the rotation angle in the Z-axis direction. Figure 6 is a diagram illustrating an example of the coordinate rotation method according to Embodiment 2.

[0052]

number

[0053] The first vibration displacement rotation unit 73 outputs a first vibration signal rotated with respect to the displacement direction (X, Y, Z) of the body surface displacement signal acquired by the radio wave sensor 2, using, for example, the coordinate rotation formula shown in equation (1) above. The second vibration displacement rotation unit 74 outputs a first vibration signal rotated with respect to the displacement direction (X, Y, Z) of the body surface displacement signal acquired by the radio wave sensor 2, using, for example, the coordinate rotation formula shown in equation (1) above. The vibration estimation unit 7a then outputs an estimated vibration component obtained by subtracting the second vibration signal output from the first vibration displacement rotation unit 73 from the second vibration signal output from the second vibration displacement rotation unit 74 as an estimated vibration signal to the vibration removal unit 8.

[0054] This makes it possible to match the displacement direction of the body surface displacement signal acquired by the radio wave sensor 2 with the vibration direction (displacement direction) of the estimated vibration signal, which is the calculation result of the vibration estimation unit 7a.

[0055] The coordinate rotation formula shown in equation (1) above is merely an example, and this disclosure is not limited thereto. A different coordinate rotation formula may be used to rotate the three-axis vibration direction detected by the first vibration sensor 31a or the second vibration sensor 32a.

[0056] According to the bio-information detection device 1a of this embodiment 2, the vibration direction of the second vibration component, which is acquired by the second vibration sensor 32a and contains a large amount of three-axis vibration components originating from the vehicle body vibration in addition to the body movement component of the subject 4, and the vibration direction of the first vibration component, which is acquired by the first vibration sensor 31 and contains a large amount of three-axis vibration components originating from the vehicle body vibration, are matched to the displacement direction of the body surface displacement signal acquired by the radio wave sensor 2. Then, the first vibration signal, which matches the displacement direction of the body surface displacement signal, is subtracted from the second vibration signal, which matches the displacement direction of the body surface displacement signal. As a result, an estimated vibration signal is obtained in which the influence of vibration components originating from the vehicle body vibration is suppressed. Then, the estimated vibration signal, which matches the displacement direction of the body surface displacement signal, is separated from the body surface displacement signal acquired by the radio wave sensor 2, and a bio-signal of the human body in which the body movement component of the subject 4 is suppressed is generated. As a result, highly accurate bio-information can be acquired, similar to embodiment 1.

[0057] In the above-described embodiment 2, an example was given of generating a first vibration signal and a second vibration signal that are rotated with respect to the displacement direction of the body surface displacement signal acquired by the radio wave sensor 2. However, it is also possible to generate a first vibration signal or a second vibration signal that is rotated with respect to the displacement direction of the body surface displacement signal acquired by the radio wave sensor 2.

[0058] (Embodiment 3) Figure 7 is a side view showing an example of application when the biometric information detection device according to Embodiment 3 is applied as a driver monitoring system for a vehicle. Figure 8 is a block diagram showing the schematic configuration of the biometric information detection device according to Embodiment 3.

[0059] The biometric information detection device 1b according to Embodiment 3 is configured to include multiple radio wave sensors 2, first vibration sensors 31, and second vibration sensors 32. Figures 7 and 8 show an example in which radio wave sensors 2A, 2B, 2C, first vibration sensors 31A, 31B, 31C, and second vibration sensors 32A, 32B, 32C are included. The first vibration sensors 31A, 31B, 31C correspond to the first vibration sensor 31 according to Embodiment 1. The second vibration sensors 32A, 32B, 32C correspond to the second vibration sensor 32 according to Embodiment 1. The configuration may also include, instead of the first vibration sensors 31A, 31B, 31C, first vibration sensors 31aA, 31aB, 31aC corresponding to the first vibration sensor 31a according to Embodiment 2, and instead of the second vibration sensors 32A, 32B, 32C, second vibration sensors 32aA, 32aB, 32aC corresponding to the second vibration sensor 32a according to Embodiment 2.

[0060] Furthermore, the biometric information detection device 1b according to Embodiment 3 is configured to include multiple radio wave sensor signal receiving units 41, first vibration sensor signal receiving units 51, and second vibration sensor signal receiving units 52, corresponding to multiple radio wave sensors 2, a first vibration sensor 31, and a second vibration sensor 32. Figure 8 shows an example in which radio wave sensor signal receiving units 41A, 41B, 41C, first vibration sensor signal receiving units 51A, 51B, 51C, and second vibration sensor signal receiving units 52A, 52B, 52C are included. Note that the first vibration sensor signal receiving units 51A, 51B, 51C correspond to the first vibration sensor signal receiving unit 51 according to Embodiment 1. The second vibration sensor signal receiving units 52A, 52B, 52C correspond to the second vibration sensor signal receiving unit 52 according to Embodiment 1. The configuration may also include, instead of the first vibration sensor signal receiving units 51A, 51B, 51C, first vibration sensor signal receiving units 51aA, 51aB, 51aC corresponding to the first vibration sensor signal receiving unit 51a according to Embodiment 2, and instead of the second vibration sensor signal receiving units 52A, 52B, 52C, second vibration sensor signal receiving units 52aA, 52aB, 52aC corresponding to the second vibration sensor signal receiving unit 52a according to Embodiment 2.

[0061] The signal processing unit 6b is configured on a dielectric substrate on which one of the radio wave sensors 2A, 2B, or 2C is provided. Furthermore, in the bio-information detection device 1b according to Embodiment 3, the signal processing unit 6b, as shown in Figure 8, includes a determination unit 9, a radio wave sensor signal selection unit 10, a first vibration sensor signal selection unit 11, and a second vibration sensor signal selection unit 12 in addition to the configuration of Embodiment 1 (or Embodiment 2). Note that the signal processing unit 6b may be configured on a substrate different from the dielectric substrate on which the radio wave sensors 2A, 2B, or 2C are provided.

[0062] In the configuration of the biological information detection device 1b according to Embodiment 3 described above, the determination unit 9 is a signal control unit that controls the radio wave sensor signal selection unit 10, the first vibration sensor signal selection unit 11, and the second vibration sensor signal selection unit 12 so as to select one of the plurality of radio wave sensors 2A, 2B, 2C, one of the plurality of first vibration sensors 31A, 31B, 31C, and one of the plurality of second vibration sensors 32A, 32B, 32C, respectively.

[0063] The radio wave sensor signal selection unit 10 outputs the body surface displacement signal selected by the determination unit 9 to the vibration removal unit 8.

[0064] The first vibration sensor signal selection unit 11 outputs the first vibration sensor signal selected by the determination unit 9 to the vibration estimation unit 7(7a).

[0065] The second vibration sensor signal selection unit 12 outputs the second vibration sensor signal selected by the determination unit 9 to the vibration estimation unit 7(7a).

[0066] In Figures 7 and 8, examples are shown of configurations equipped with three radio wave sensors 2, a first vibration sensor 31, and a second vibration sensor 32, respectively. However, the number of radio wave sensors 2, first vibration sensors 31, and second vibration sensors 32 is not limited to three. The number of radio wave sensors 2, first vibration sensors 31, and second vibration sensors 32 may be two, or four or more. Furthermore, the number of radio wave sensors 2, first vibration sensors 31, and second vibration sensors 32 do not have to be the same.

[0067] The body surface displacement signal acquired by the radio wave sensor 2 has a different intensity depending on the position of the subject 4's body to which the electromagnetic waves emitted by the radio wave sensor 2 hit. Specifically, the optimal electromagnetic wave irradiation position differs between taller and shorter subjects. In other words, the intensity of the body surface displacement signal acquired by each radio wave sensor 2A, 2B, and 2C differs depending on the seating position of subject 4 on the seat 5.

[0068] The determination unit 9, for example, compares the body surface displacement signals acquired by each radio wave sensor 2A, 2B, and 2C, selects the body surface displacement signal with the largest received intensity (received power), selects the first vibration sensor signal acquired by the first vibration sensor 31 (31a) provided on the same dielectric substrate as the radio wave sensor 2 that acquired the body surface displacement signal, and selects the second vibration sensor signal acquired by the second vibration sensor 32 (32a) located at a relatively close distance from the first vibration sensor 31 (31a) that acquired the first vibration sensor signal.

[0069] The determination unit 9 may, for example, determine the correlation between the selected radio wave sensor signal and the estimated vibration signal output from the vibration estimation unit 7(7a), and re-select one or both of the first vibration sensor signal and the second vibration sensor signal. Specifically, the determination unit 9 may, for example, calculate the correlation coefficient between the selected radio wave sensor signal and the estimated vibration signal output from the vibration estimation unit 7(7a), and if the calculated correlation coefficient falls below a predetermined threshold, re-select one or both of the first vibration sensor signal and the second vibration sensor signal and perform the same correlation coefficient calculation process. Then, the determination unit 9 may select a combination of the first vibration sensor signal and the second vibration sensor signal whose correlation coefficient is equal to or greater than the predetermined threshold.

[0070] The bio-information detection device 1b according to this embodiment 3 is equipped with multiple radio wave sensors 2, first vibration sensors 31, and second vibration sensors 32. Therefore, the optimal body surface displacement signal, first vibration sensor signal, and second vibration sensor signal are selected according to the height and build of the subject 4, or the driving position (driving posture), etc. Then, the estimated vibration signal obtained from the selected first vibration sensor signal and second vibration sensor signal is separated from the selected body surface displacement signal, and a bio-signal of the human body with the body movement component of the subject 4 suppressed is generated. As a result, highly accurate bio-information can be obtained with the variation due to the height and build of the subject 4, or the driving position (driving posture), etc.

[0071] The embodiments described above are provided to facilitate understanding of this disclosure and are not intended to limit the invention. This disclosure may be modified or improved without departing from its spirit, and equivalents thereof are included.

[0072] This disclosure may take the following configuration, as described above, or alternatively.

[0073] (1) A biological information detection device according to one aspect of the present disclosure includes: a radio wave sensor for detecting surface displacement of the human body; a first vibration sensor installed together with the radio wave sensor at a position away from the holding surface that holds the human body; a second vibration sensor installed closer to the holding surface than the first vibration sensor; and a signal processing unit that generates a biological signal of the human body based on the surface displacement acquired by the radio wave sensor, a first vibration component acquired by the first vibration sensor, and a second vibration component acquired by the second vibration sensor.

[0074] In this configuration, biosignals of the human body are generated based on body surface displacement acquired by a radio wave sensor, a first vibration component acquired by a first vibration sensor, and a second vibration component acquired by a second vibration sensor. This makes it possible to suppress both the influence of the subject's body movement and the influence of vibration components originating from the body vibration of a vehicle (e.g., an automobile).

[0075] (2) In the biological information detection device described in (1) above, the signal processing unit comprises a vibration estimation unit that subtracts the first vibration component from the second vibration component to generate an estimated vibration component, and a vibration removal unit that separates the estimated vibration component from the body surface displacement.

[0076] In this configuration, the first vibration component, which contains a large amount of vibration components originating from the vehicle's body vibration, is subtracted from the second vibration component, which contains vibration components originating from the vehicle's body vibration. This allows for the acquisition of an estimated vibration component that suppresses the influence of vibration components originating from the vehicle's body vibration, for example. The estimated vibration component can then be separated from the body surface displacement acquired by the radio wave sensor.

[0077] (3) In the biological information detection device described in (2) above, the vibration removal unit generates the biological signal using an adaptive filter.

[0078] In this configuration, biosignals from the human body are generated with suppressed body movement components. This allows for the acquisition of highly accurate biological information.

[0079] (4) In the biological information detection device described in (2) above, the vibration estimation unit rotates at least one of the first vibration component and the second vibration component.

[0080] In this configuration, the displacement direction of the body surface displacement acquired by the radio wave sensor can be matched with the vibration direction (displacement direction) of the estimated vibration component, which is the calculation result of the vibration estimation unit.

[0081] (5) In the biological information detection device described in (4) above, the vibration removal unit generates the biological signal using an adaptive filter.

[0082] In this configuration, biosignals from the human body are generated with suppressed body movement components. This allows for the acquisition of highly accurate biological information.

[0083] (6) In the biological information detection device described in (2) to (5) above, the device comprises at least one of the radio wave sensor, the first vibration sensor, and the second vibration sensor, and the signal processing unit appropriately selects the combination of the body surface displacement, the first vibration component, and the second vibration component when generating the biological signal.

[0084] In this configuration, at least one of the optimal body surface displacement, first vibration component, or second vibration component can be selected from multiple options based on the subject's height, build, or driving position. This allows for the acquisition of highly accurate biological information while suppressing variations due to the subject's height, build, or driving position.

[0085] (7) In the biological information detection device described in (6) above, a plurality of radio wave sensors may be provided, and the signal processing unit may include a radio wave sensor signal selection unit that selects one of the body surface displacements acquired by the plurality of radio wave sensors.

[0086] (8) In the biological information detection device described in (6) above, a plurality of first vibration sensors may be provided, and the signal processing unit may include a first vibration sensor signal selection unit that selects one of the first vibration components acquired by the plurality of first vibration sensors.

[0087] (9) In the biological information detection device described in (6) above, a plurality of the second vibration sensors may be provided, and the signal processing unit may include a second vibration sensor signal selection unit that selects one of the second vibration components acquired by the plurality of the second vibration sensors.

[0088] (10) A vehicle in one aspect of this disclosure is equipped with the biometric information detection devices described in (1) to (9) above.

[0089] This configuration makes it possible to realize a vehicle equipped with a biometric information detection device that can acquire highly accurate biological information by suppressing both the influence of the subject's body movement components and the influence of vibration components originating from the vehicle's body vibration.

[0090] This disclosure makes it possible to realize a biometric information detection device capable of acquiring highly accurate biological information, and a vehicle equipped therewith. [Explanation of Symbols]

[0091] 1,1a,1b Biometric information detection device 2. Radio wave sensor 3 cabinets 4 subjects 5 sheets 5a Internal material 5b Surface material 6,6a Signal Processing Unit 7,7a Vibration estimation part 8 Vibration removal section 8a filter 8b Adaptive Processing Unit 9 Judgment section 10. Radio wave sensor signal selection unit 11. First vibration sensor signal selection unit 12 Second vibration sensor signal selection unit 31, 31A, 31B, 31C, 31a, 31aA, 31aB, 31aC First vibration sensor 32, 32A, 32B, 32C, 32a, 32aA, 32aB, 32aC Second vibration sensor 41, 41A, 41B, 41C Radio wave sensor signal receiving unit 51, 51A, 51B, 51C, 51a, 51aA, 51aB, 51aC First vibration sensor signal receiving unit 52, 52A, 52B, 52C, 52a, 52aA, 52aB, 52aC Second vibration sensor signal receiving unit 71 First displacement transformation unit 72 Second displacement conversion section 73 First vibration displacement rotation section 74 Second vibration displacement rotation section

Claims

1. A radio wave sensor that detects displacement of the human body surface, A first vibration sensor is installed together with the aforementioned radio wave sensor, at a position away from the holding surface that holds the human body, A second vibration sensor is installed in a position closer to the holding surface than the first vibration sensor, A signal processing unit that generates a biosignal of the human body based on the body surface displacement acquired by the radio wave sensor, the first vibration component acquired by the first vibration sensor, and the second vibration component acquired by the second vibration sensor, Equipped with, Biometric information detection device.

2. A biological information detection device according to claim 1, The signal processing unit, A vibration estimation unit that subtracts the first vibration component from the second vibration component to generate an estimated vibration component, A vibration removal unit that separates the estimated vibration component from the body surface displacement, Equipped with, Biometric information detection device.

3. A biological information detection device according to claim 2, The vibration removal unit generates the biosignal using an adaptive filter. Biometric information detection device.

4. A biological information detection device according to claim 2, The vibration estimation unit rotates at least one of the first vibration component and the second vibration component. Biometric information detection device.

5. A biological information detection device according to claim 4, The vibration removal unit generates the biosignal using an adaptive filter. Biometric information detection device.

6. A biological information detection device according to any one of claims 2 to 5, The system comprises at least one of the radio wave sensor, the first vibration sensor, and the second vibration sensor, The signal processing unit, When generating the aforementioned biological signal, an appropriate combination of the body surface displacement, the first vibration component, and the second vibration component is selected. Biometric information detection device.

7. A biological information detection device according to claim 6, Equipped with multiple radio wave sensors, The signal processing unit, It includes a radio wave sensor signal selection unit that selects one of the body surface displacements acquired by multiple radio wave sensors. Biometric information detection device.

8. A biological information detection device according to claim 6, Equipped with multiple first vibration sensors, The signal processing unit, The system includes a first vibration sensor signal selection unit that selects one of the first vibration components acquired by a plurality of the first vibration sensors. Biometric information detection device.

9. A biological information detection device according to claim 6, Equipped with multiple second vibration sensors, The signal processing unit, The system includes a second vibration sensor signal selection unit that selects one of the second vibration components acquired by a plurality of the second vibration sensors. Biometric information detection device.

10. A biological information detection device according to any one of claims 1 to 5, vehicle.

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