Biological information detection device

Abstract

To enable the detection of biological information with high accuracy while suppressing an increase in cost.SOLUTION: A biological information detection device includes: a sensor that transmits a frequency-modulated electromagnetic wave to a room of a moving body as a transmission wave and receives a reflected wave generated by reflection of the transmission wave on an object present in the room; a position information generation section that generates position information indicating a position of the object in the room on the basis of the reflected wave; a speed information generation section that generates speed information indicating speed of the object on the basis of the reflected wave; a person detection section that detects a person present in the room on the basis of the position information and the speed information; a correction section that performs correction processing for removing a vibration component corresponding to vibration of the moving body from the speed information corresponding to a motion of the person; and a biological information generation section that generates biological information about the person on the basis of high-speed region speed information, that is speed information on which the correction processing is performed and which corresponds to speed faster than predetermined speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a biological information detection device. [Background technology]

[0002] In driver monitoring systems and the like, a technology is used to detect biometric information (e.g., heartbeat interval, heart rate, etc.) of occupants of a moving body (vehicle, etc.) based on TOF (Time of Flight) information, Doppler shift information, etc. acquired by a sensor that transmits and receives FMCW (Frequency Modulated Continuous Wave) radio waves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-168379 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described system, in order to detect biological information with high accuracy, it is necessary to remove vibration components caused by the vibration of the moving body from the data acquired by the sensor. The vibration components to be removed include high-speed vibration components corresponding to relatively high vibration velocities and low-speed vibration components corresponding to relatively slow vibration velocities. In order to accurately detect and remove the low-speed vibration components, the sensor needs to have high resolution, which increases costs.

[0005] Therefore, one of the problems to be solved by the present invention is to provide a biological information detection device that can detect biological information with high accuracy while suppressing an increase in cost. [Means for solving the problem]

[0006] A biometric information detection device according to one embodiment of the present invention comprises a sensor that transmits frequency-modulated electromagnetic waves as transmission waves into a room of a moving body and receives reflected waves generated when the transmission waves are reflected by an object present in the room; a position information generation unit that generates position information indicating the position of the object in the room based on the reflected waves; a speed information generation unit that generates speed information indicating the speed of the object based on the reflected waves; a person detection unit that detects a person present in the room based on the position information and speed information; a correction unit that performs correction processing to remove vibration components corresponding to vibrations of the moving body from speed information corresponding to the movement of the person; and a biometric information generation unit that generates biometric information of the person based on high-speed range speed information that has been corrected and is speed information corresponding to a speed equal to or greater than a predetermined speed. The correction process is performed based on the difference between the complex velocity distribution, which is a velocity distribution based on the complex intensity of the reflected wave contained in the voxel values ​​of the voxels that make up the labeling area determined to be a person in a voxel diagram showing the arrangement of objects in a room, and the absolute velocity distribution, which is a velocity distribution based on the absolute value of the intensity of the reflected wave.

[0007] Vibration components at or above a predetermined speed can be removed relatively accurately by the correction process. Therefore, with the above configuration, highly accurate biometric information can be generated using high-speed range speed information from which vibration components have been accurately removed.

[0010] The predetermined speed may also be 10 km / h.

[0011] This makes it possible to reduce costs while improving the accuracy of detecting biological information.

[0012] The biometric information may also include heart rate information relating to the person's heart rate.

[0013] This makes it possible to obtain highly accurate heart rate information of the occupant that can be used to control the vehicle. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a vehicle according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of a functional configuration of the sensor and the control device according to the embodiment. [Figure 3] FIG. 3 is a diagram showing an outline of signal processing by the FMCW method according to the embodiment. [Figure 4] FIG. 4 is a flowchart illustrating an example of processing performed by the biological information detection device according to the embodiment. [Figure 5] FIG. 5 is a flowchart illustrating an example of a process for generating high speed range speed information according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions, results, and advantages brought about by the configurations, are merely examples. The present invention can be realized using configurations other than those disclosed in the following embodiments, and it is possible to obtain at least one of the various advantages and derivative advantages based on the basic configurations.

[0016] FIG. 1 is a diagram showing an example of the configuration of a vehicle C according to an embodiment. A sensor 2 and a control device 3 constituting a biological information detection device 1 are arranged inside the vehicle C (an example of a moving body). The sensor 2 according to this embodiment is installed on the ceiling of the vehicle. The control device 3 according to this embodiment is installed inside a dashboard provided at the front end of the vehicle. However, the installation positions of the sensor 2 and the control device 3 are not limited to this.

[0017] FIG. 1 illustrates an example in which an occupant M (person) is sitting in a seat S. The following describes how the biometric information detection device 1 detects the presence of the occupant M and detects the biometric information of the occupant M. Note that FIG. 1 illustrates an example in which the occupant M is sitting in the rear seat, but the position of the occupant M to be detected is not limited to this. For example, an occupant sitting in the driver's seat or the passenger seat may be the detection target.

[0018] 2 is a block diagram showing an example of the functional configuration of the sensor 2 and the control device 3 according to the embodiment. The sensor 2 includes a transmitting unit 21 and a receiving unit 22.

[0019] The transmitter 21 transmits (irradiates) frequency-modulated electromagnetic waves as transmission waves over a wide range within the interior of the vehicle C. The receiver 22 receives reflected waves that are generated when the transmission waves are reflected by objects present within the interior.

[0020] The control device 3 is configured by, for example, an MCU (Micro Controller Unit) having an integrated circuit equipped with a hardware processor, a memory, etc. The control device 3 includes an ADC (Analog-to-Digital Converter) 31, a processing unit 32, and a storage unit 33.

[0021] The ADC 31 converts the analog signal acquired by the receiving unit 22 of the sensor 2 into a digital signal and outputs the digital signal to the processing unit 32 .

[0022] The storage unit 33 is, for example, a storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), an SSD (Solid State Drive), or an HDD (Hard Disk Drive). The storage unit 33 stores programs executed by the processing unit 32, data required for executing the programs, data generated by executing the programs, etc. The storage unit 33 of this embodiment stores setting information 331, position information 332, speed information 333, biometric information 334, etc.

[0023] The setting information 331 includes various thresholds for realizing the functions of the biological information detection device 1. The thresholds may be, for example, a threshold for determining whether an object present in a room is a living thing or a non-living thing, a threshold for determining whether a living thing is a person, a threshold for determining whether a person is an adult or a child, a threshold for detecting a biological signal of a person, etc.

[0024] The position information 332 is information indicating the position of an object present in the room, and is generated based on the intensity distribution of the reflected wave in the room by the position information generating unit 321. The intensity distribution is information indicating the correspondence between the position of the reflection source (object) in three-dimensional space (the room of vehicle C) and the intensity of the reflected wave.

[0025] The velocity information 333 is information indicating the velocity of an object present in the room, and is generated based on the Doppler shift of the reflected wave by the velocity information generating unit 322. The velocity information 333 may include information indicating the direction of movement of the object.

[0026] The biological information 334 is information relating to the body and mind of the occupant M present in the cabin, and is generated by the biological information generation unit 325 based on the speed information 333 and the like corresponding to the occupant M. The biological information in this embodiment includes information relating to the heartbeat of the occupant M (e.g., heartbeat interval, heart rate, etc.). The biological information can be detected based on the speed information 333 and the like corresponding to the movement of a predetermined part of the occupant M (e.g., chest, back, etc.). The biological information may include information indicating the physical condition, mental state, etc. inferred from the information relating to the heartbeat.

[0027] Here, an overview of signal processing using the FMCW method will be described. Fig. 3 is a diagram showing an overview of signal processing using the FMCW method according to an embodiment. First, as shown in state (A), an FMCW-modulated electromagnetic wave is transmitted from the transmitter 21 of the sensor 2 into the interior of the vehicle C. Then, the receiver 22 of the sensor 2 receives the reflected wave.

[0028] Next, as shown in state (B), a voxel diagram showing the arrangement (including position, size, shape, etc.) of objects in three-dimensional space (the interior) is created based on the intensity distribution of the reflected waves in the interior. Each voxel constituting the voxel diagram has a voxel value including coordinate values ​​(x, y, z) indicating a position in three-dimensional space (a Cartesian coordinate system consisting of the x-, y-, and z-axes) and the intensity (complex number) of the reflected waves. The voxel diagram includes a labeling area D indicating the arrangement of objects present in the interior (e.g., occupant M, seat S, luggage, other vehicle structures, etc.). The voxel diagram is updated as the reflected wave information acquired by sensor 2 is updated. Information regarding the position and speed of objects can be obtained by analyzing such changes in the voxel diagram. For example, by performing FFT (Fast Fourier Transform) analysis on the difference between adjacent frames of the voxel diagram, the Doppler shift of the reflected waves and the speed distribution indicating the relationship between speed and the strength of the reflected waves can be calculated.

[0029] Next, as shown in state (C), an occupant M present in the vehicle cabin is detected based on the analysis results of the voxel values ​​of the voxels that make up the labeling area D. For example, among multiple objects present in the vehicle cabin, an object that satisfies predetermined conditions (size, shape, speed, etc.) can be determined to be the occupant M. Furthermore, the biological information of the occupant M can be detected based on the movement of a predetermined part (e.g., chest, back, etc.) of the object determined to be the occupant M.

[0030] The processing of the processing unit 32 will be described below with reference to FIG.

[0031] The processing unit 32 is configured by a hardware processor such as a CPU (Central Processing Unit). The processing unit 32 reads a program stored in the storage unit 33 and executes arithmetic processing. The processing unit 32 includes, as functional units, a position information generation unit 321, a speed information generation unit 322, a person detection unit 323, a correction unit 324, and a biometric information generation unit 325. Note that some or all of the units 321 to 325 may be configured by hardware such as a circuit including an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0032] The position information generating unit 321 generates indoor position information 332 based on information about the reflected wave (reflected wave information) acquired from the ADC 31, and stores the information in the storage unit 33. The position information can be generated based on the analysis results of the voxel diagram as described above, for example.

[0033] The velocity information generating unit 322 generates velocity information 333 indicating the velocity of an object present in the room based on the reflected wave information acquired from the ADC 31, and stores the velocity information 333 in the storage unit 33. The velocity information 333 can be generated based on, for example, the analysis results of the voxel diagram described above.

[0034] The person detection unit 323 detects an occupant M present in the cabin of the vehicle C based on the setting information 331, the position information 332, the speed information 333, etc. The person detection unit 323 may also determine the type of the occupant M (for example, an adult, a child, etc.).

[0035] The correction unit 324 performs a correction process to remove vibration components corresponding to vibrations of the vehicle C from the velocity information 333 corresponding to the movement of the occupant M. The correction process in this embodiment is performed based on a velocity distribution that indicates the relationship between the velocity of the occupant M and the intensity of the reflected wave from the occupant M. The correction process can be performed, for example, based on the difference between a complex velocity distribution that is a velocity distribution based on the complex intensity of the reflected wave included in the voxel values ​​of the voxels that make up the labeling region D determined to be that of the occupant M in a voxel diagram that indicates the arrangement of objects present in the cabin, and an absolute velocity distribution that is a velocity distribution based on the absolute value of the intensity of the reflected wave.

[0036] The biometric information generating unit 325 generates biometric information 324 of the occupant M based on the high speed range speed information that has been corrected and is speed information corresponding to a speed equal to or greater than a predetermined speed. The predetermined speed is based on the resolution of the sensor 2, and can be set lower as the resolution of the sensor 2 is higher. The predetermined speed can be, for example, 10 km / h. The generated biometric information 324 is stored in the storage unit 33.

[0037] 4 is a flowchart showing an example of processing by the biological information detection device 1 according to the embodiment. When reflected wave information from inside the vehicle C is acquired by driving the sensor 2 (S101), the position information generating unit 321 generates position information 332 indicating the position of an object inside the vehicle C based on the intensity distribution of the reflected wave (S102), and the speed information generating unit 322 generates speed information 333 indicating the speed of the object based on the Doppler shift of the reflected wave (S103).

[0038] The person detection unit 323 determines whether or not an occupant M is present in the cabin of the vehicle C based on the position information 332 and the speed information 333 (S104). If an occupant M is not present (S104: No), this routine ends. If an occupant M is present (S104: Yes), the correction unit 324 performs correction processing on the speed information 333 of the occupant M (S105). The biometric information generation unit 325 generates biometric information based on the high-speed range speed information that has been corrected and is speed information that corresponds to a speed equal to or greater than a predetermined speed (S106).

[0039] In a high speed range above a predetermined speed, vibration components can be removed relatively accurately even if the resolution of the sensor 2 is relatively low. Therefore, by performing the above-described processing, highly accurate biological information can be generated using high speed range speed information from which vibration components have been accurately removed.

[0040] Fig. 5 is a flowchart showing an example of processing when generating high-speed range speed information according to an embodiment. First, voxel values ​​of a region corresponding to the occupant M are acquired from a voxel diagram such as that shown in Fig. 3 (S201). These voxel values ​​include values ​​(x, y, z) indicating a position in three-dimensional space (orthogonal coordinate system) and the intensity (complex number) of the reflected wave at that position.

[0041] Then, a complex velocity distribution showing the relationship between velocity and the intensity of the complex number is calculated by FFT analysis of the time series change (difference between adjacent frames) of the intensity (complex number) of the acquired reflected wave (S202).Furthermore, an absolute velocity distribution showing the relationship between velocity and the absolute value of the intensity is calculated by FFT analysis of the time series change of the absolute value of the intensity of the acquired reflected wave (S203).

[0042] Thereafter, the difference between the complex velocity distribution and the absolute velocity distribution in a velocity range of 10 km / h (an example of a predetermined velocity) or higher is calculated (S204), and high-speed region velocity information is generated by performing an inverse FFT analysis on the difference (S205).

[0043] According to the above embodiment, the biological information is generated using the high speed range speed information from which the vibration component of the vehicle C has been accurately removed. This allows the biological information to be detected with high accuracy without increasing costs, such as by using a sensor 2 with high resolution.

[0044] The program executed by the control device 3 may be provided as a computer program product stored in an installable or executable file format on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD (Digital Versatile Disk), or flexible disk (FD). Alternatively, the program may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Alternatively, the program may be provided or distributed via a network such as the Internet.

[0045] Although the embodiments of the present invention have been described above, the above embodiments are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0046] 1...biometric information detection device, 2...sensor, 3...control device, 21...transmitting unit, 22...receiving unit, 31...ADC, 32...processing unit, 33...storage unit, 321...position information generating unit, 322...speed information generating unit, 323...person detecting unit, 324...correction unit, 325...biometric information generating unit, 331...setting information, 332...position information, 333...speed information, 334...biometric information, C...vehicle, D...labeling area, M...occupant, S...seat

Claims

1. a sensor that transmits a frequency-modulated electromagnetic wave as a transmission wave into a room of the mobile body and receives a reflected wave generated when the transmission wave is reflected by an object present in the room; a position information generating unit that generates position information indicating a position of the object in the room based on the reflected wave; a velocity information generating unit that generates velocity information indicating the velocity of the object based on the reflected wave; a person detection unit that detects a person present in the room based on the position information and the velocity information; a correction unit that performs correction processing to remove a vibration component corresponding to the vibration of the moving object from the velocity information corresponding to the movement of the person; a biometric information generating unit that generates biometric information of the person based on high speed range speed information that has been subjected to the correction process and corresponds to a speed equal to or greater than a predetermined speed; Equipped with the correction process is performed based on a difference between a complex velocity distribution, which is a velocity distribution based on the complex intensity of the reflected wave included in voxel values ​​of voxels constituting a labeling region determined to be the person in a voxel diagram showing the arrangement of the object in the room, and an absolute velocity distribution, which is a velocity distribution based on the absolute value of the intensity of the reflected wave. Biometric information detection device.

2. The predetermined speed is 10 km / h. The biological information detection device according to claim 1 .

3. The biological information includes heart rate information regarding the heart rate of the person.

3. The biological information detecting device according to claim 1.

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