Biological information detection device

Abstract

To provide a biological information detection device capable of detecting biological information on a crew member of a movable body with a high degree of precision.SOLUTION: A biological information detection device includes: a sensor for transmitting a transmission wave and receiving a reflection wave generated when the transmission wave is reflected by an object present in a room; a position information generation unit for generating position information indicating the position of the object in the room on the basis of the reflection wave; a velocity information generation unit for generating velocity information indicating the velocity of the object on the basis of the reflection wave; a person detection unit for detecting a person present in the room on the basis of the position information and the velocity information; a sub-velocity information generation unit for generating sub-velocity information indicating the velocity corresponding to a motion of a part of the person's body on the basis of a sub-beat frequency component that does not include a main beat frequency corresponding to a maximum peak in the beat frequency intensity distribution indicating relationships between a beat frequency based on a difference between the frequency of the transmission wave and the frequency of the reflection wave, and the intensity of the reflection wave; and a biological information generation unit for generating biological information on the person on the basis of the sub-velocity information.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, 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), Doppler shift, etc. acquired by a sensor that transmits and receives FMCW (Frequency Modulated Continuous Wave) electromagnetic 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 components caused by vibrations of the moving body from the data acquired by the sensor.

[0005] Therefore, one of the problems to be solved by the present invention is to provide a biological information detection device capable of detecting biological information of an occupant of a mobile body with high accuracy. [Means for solving the problem]

[0006] A biometric information detection device according to one embodiment of the present invention includes a sensor that transmits frequency-modulated laser light as a transmission wave into a room of a moving body and receives a reflected wave generated when the transmission wave is 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 wave; a speed information generation unit that generates speed information indicating the speed of the object based on the reflected wave; a human detection unit that detects a person present in the room based on the position information and the speed information; a sub-speed information generation unit that generates sub-speed information indicating the speed corresponding to the movement of a part of the person's body based on sub-beat frequency components that do not include a main beat frequency that corresponds to a maximum peak in a beat frequency intensity distribution that indicates the relationship between a beat frequency based on a difference between the frequency of the transmission wave and the frequency of the reflected wave and the intensity of the reflected wave; and a biometric information generation unit that generates biometric information of the person based on the sub-speed information.

[0007] According to the above configuration, the biometric information of the occupant is generated based on the secondary speed information based on the secondary beat frequency component from which the vibration component of the moving body has been removed, thereby enabling the biometric information of the occupant of the moving body that generates vibration to be detected with high accuracy.

[0008] The secondary velocity information generating unit may generate a first beat frequency intensity distribution, which is a beat frequency intensity distribution based on a first transmission wave whose frequency increases over time and a first reflected wave generated when the first transmission wave is reflected by the object, and a second beat frequency intensity distribution, which is a beat frequency intensity distribution based on a second transmission wave whose frequency decreases over time and a second reflected wave generated when the second transmission wave is reflected by the object; calculate a Doppler frequency based on a first main beat frequency corresponding to a maximum peak in the first beat frequency intensity distribution and a second main beat frequency corresponding to a maximum peak in the second beat frequency intensity distribution; and extract a secondary beat frequency component from the difference between a first corrected beat frequency intensity distribution obtained by correcting the first beat frequency intensity distribution based on the Doppler frequency and a second corrected beat frequency intensity distribution obtained by correcting the second beat frequency intensity distribution based on the Doppler frequency.

[0009] By using this method, it is possible to extract the sub-beat frequency components from which the vibration components have been effectively removed.

[0010] The sub-beat frequency component may be composed of beat frequencies equal to or greater than a reference frequency that is higher than the main beat frequency by a predetermined frequency.

[0011] This makes it possible to achieve high detection accuracy even when a sensor with a relatively low resolution is used. [Brief explanation of the drawings]

[0012] [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 diagram illustrating an example of characteristics of a transmitted wave, a reflected wave, and a beat frequency according to the embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of processing for extracting sub beat frequency components from the beat frequency intensity distribution according to the embodiment. [Figure 6] FIG. 6 is a diagram showing another example of the secondary beat frequency component according to the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of processing performed by the biological information detecting device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] 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.

[0014] FIG. 1 is a diagram showing an example of the configuration of a vehicle C according to an embodiment. A LiDAR (Light Detection and Ranging) 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 LiDAR 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 LiDAR sensor 2 and the control device 3 are not limited to this.

[0015] 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.

[0016] 2 is a block diagram showing an example of the functional configuration of the LiDAR sensor 2 and the control device 3 according to the embodiment. The LiDAR sensor 2 includes a transmitter 21 and a receiver 22.

[0017] The transmitter 21 transmits frequency-modulated laser light as a transmission wave over a wide range within the interior of the vehicle C. The receiver 22 receives a reflected wave that is generated when the transmission wave is reflected by an object present within the interior.

[0018] 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.

[0019] The ADC 31 converts the analog signal acquired by the receiving unit 22 of the LiDAR sensor 2 into a digital signal and outputs the digital signal to the processing unit 32.

[0020] 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, sub-speed information 334, biometric information 335, etc.

[0021] 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.

[0022] 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.

[0023] The speed information 333 indicates the speed of an object present in the room, and is generated based on the Doppler shift of the reflected wave by the speed information generating unit 322. The speed information 333 indicates the speed corresponding to the overall movement of each object recognized as present in the room (for example, the movement of the center of the object).

[0024] The secondary speed information 334 is information indicating the speed corresponding to the movement of a part of the body of a person (occupant M) present in the room, and is generated by the secondary speed information generation unit 324. The movement of a part of the body is the movement of a part other than the main part of the occupant M (for example, the central part of the body of the occupant M), and may be, for example, pulsation appearing in the chest, back, arms, etc.

[0025] The biological information 335 is information about the physical and mental state of the occupant M present in the cabin, and is generated based on the secondary speed information 334, etc. The biological information includes information about the heartbeat of the occupant M (e.g., heartbeat interval, heart rate, etc.), and may also include information indicating the physical condition, mental state, etc. inferred from the information about the heartbeat.

[0026] 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), FMCW-modulated laser light is transmitted from the transmitter 21 of the LiDAR sensor 2 so as to scan the entire interior of the vehicle C. Then, the receiver 22 of the LiDAR sensor 2 receives the reflected wave.

[0027] Next, as shown in state (B), a voxel diagram showing the arrangement (including position, size, shape, etc.) of objects in three-dimensional space (indoor vehicle) is created based on the intensity distribution of the reflected waves in the vehicle. The voxel diagram includes a labeling area D showing the arrangement of objects present in the vehicle (occupant M, seat S, luggage, other vehicle body structures, etc.). The voxel diagram is updated as the reflected wave information acquired by the LiDAR 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, the Doppler shift of the reflected waves can be calculated by performing FFT (Fast Fourier Transform) analysis on the difference between adjacent frames of the voxel diagram.

[0028] 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 part of the object determined to be the occupant M (for example, the chest, back, etc.).

[0029] The processing of the processing unit 32 will be described below with reference to FIG.

[0030] 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 sub-speed information generation 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).

[0031] The position information generating unit 321 generates position information 332 indicating the position of an object present in the room 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, for example, the analysis results of the voxel diagram described above.

[0032] 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.

[0033] The person detection unit 323 detects an occupant M present in the vehicle cabin 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.).

[0034] The secondary speed information generating unit 324 generates secondary speed information indicating the speed corresponding to the movement of a part of the body of the occupant M based on the reflected wave information acquired from the ADC 31, the detection results by the person detecting unit 323, etc., and stores the generated secondary speed information in the storage unit 33. The secondary speed information generating unit 324 generates the secondary speed information using a beat frequency intensity distribution indicating the relationship between the beat frequency based on the difference between the frequency of the transmitted wave and the frequency of the reflected wave and the intensity of the reflected wave. The secondary speed information generating unit 324 generates the secondary speed information based on secondary beat frequency components that do not include the main beat frequency corresponding to the maximum peak in the beat frequency intensity distribution. A specific method for generating the secondary speed information will be described later.

[0035] The biometric information generating unit 325 generates biometric information 335 of the occupant M based on the secondary speed information generated by the secondary speed information generating unit 324 and stores it in the storage unit 33.

[0036] Fig. 4 is a diagram illustrating an example of characteristics of a transmitted wave, a reflected wave, and a beat frequency according to an embodiment. In Fig. 4, the upper graph illustrates a line Lt showing the relationship between elapsed time and the frequency of a transmitted wave transmitted from the transmitter 21 of the LiDAR sensor 2, and a line Lr showing the relationship between elapsed time and the frequency of a reflected wave received by the receiver 22 of the LiDAR sensor 2. In Fig. 4, the lower graph illustrates a line Lb showing the relationship between elapsed time and the beat frequency.

[0037] As shown by line Lt, the transmission wave in this embodiment is a chirp signal that alternates between an up period T1, in which the frequency increases over time, and a down period T2, in which the frequency decreases over time. One up period T1 and one down period T2 constitute one chirp period T. As shown by line Lr, the frequency of the reflected wave changes with a delay corresponding to the distance from the LiDAR sensor 2 to the object, relative to the change in the frequency of the transmission wave over time. In other words, a difference occurs between the frequency of the transmission wave and the frequency of the reflected wave at the same time. The beat frequency is a value determined by this difference, is proportional to the distance from the LiDAR sensor 2 to the object, and changes according to the movement of the target object.

[0038] The secondary speed information generating unit 324 of this embodiment extracts secondary beat frequency components corresponding to the movement of a part of the body of the occupant M from the beat frequency intensity distribution that indicates the relationship between the beat frequency and the intensity of the reflected wave as described above, and generates secondary speed information based on the secondary beat frequency components. An example of a method for extracting secondary beat frequency components from the beat frequency intensity distribution is shown below.

[0039] 5 is a diagram illustrating an example of a process for extracting sub-beat frequency components from a beat frequency intensity distribution according to an embodiment, which illustrates a first beat frequency intensity distribution D1, a second beat frequency intensity distribution D2, a first corrected beat frequency intensity distribution D1′, a second corrected beat frequency intensity distribution D2′, and a differential beat frequency intensity distribution D3.

[0040] The first beat frequency intensity distribution D1 is a beat frequency intensity distribution based on a first transmission wave, which is a transmission wave corresponding to the up period T1, and a first reflected wave, which is a reflected wave generated when the first transmission wave is reflected by the occupant M. In other words, the first beat frequency intensity distribution D1 is data indicating the relationship between a beat frequency based on the difference between the frequency of the first transmission wave and the frequency of the first reflected wave, and the intensity of the first reflected wave. Such a first beat frequency intensity distribution D1 can be created, for example, by FFT (Fast Fourier Transform) analysis of the beat frequency corresponding to the up period T1.

[0041] The second beat frequency intensity distribution D2 is a beat frequency intensity distribution based on a second transmission wave, which is a transmission wave corresponding to a down period T2 included in the same chirp period T as the up period T1, and a second reflected wave, which is a reflected wave generated when the second transmission wave is reflected by the occupant M. In other words, the second beat frequency intensity distribution D2 is data indicating the relationship between the beat frequency, which is based on the difference between the frequency of the second transmission wave and the frequency of the second reflected wave, and the intensity of the second reflected wave. Such a second beat frequency intensity distribution D2 can be created, for example, by FFT analysis of the beat frequency corresponding to the down period T2.

[0042] The first main beat frequency f1 corresponding to the maximum peak P1 in the first beat frequency intensity distribution D1 and the second main beat frequency f2 corresponding to the maximum peak P2 in the second beat frequency intensity distribution D2 both correspond to the same position (distance from the LiDAR sensor 2) of the main part of the occupant M (e.g., the center of the body, etc.). The first main beat frequency f1 and the second main beat frequency f2 are shifted by a Doppler frequency fd from the main beat frequency f0 corresponding to the original position of the main part of the occupant M. The Doppler frequency fd can be calculated based on the first main beat frequency f1 and the second main beat frequency f2. For example, the Doppler frequency fd can be calculated using the formula fd = (f2 - f1) / 2. That is, the Doppler frequency fd can be calculated based on the first main beat frequency f1 and the second main beat frequency f2, and the main beat frequency f0 can be calculated based on the first main beat frequency f1, the second main beat frequency f2, and the Doppler frequency fd.

[0043] The first corrected beat frequency intensity distribution D1' is obtained by correcting the first beat frequency intensity distribution D1 based on the Doppler frequency fd so that the first main beat frequency f1 coincides with the main beat frequency f0. The second corrected beat frequency intensity distribution D2' is obtained by correcting the second beat frequency intensity distribution D2 based on the Doppler frequency fd so that the second main beat frequency f2 coincides with the main beat frequency f0.

[0044] The first corrected beat frequency intensity distribution D1' shows that first minor beat frequency components Fl1 and Rf1 are present in a region shifted from the main beat frequency f0. The first minor beat frequency component Fl1 includes beat frequency components lower in frequency than the main beat frequency f0, and the first minor beat frequency component Fh1 includes beat frequency components higher in frequency than the main beat frequency f0. The first minor beat frequency components Fl1 and Fh1 include beat frequency components corresponding to movements of parts of the occupant M other than their main body (e.g., pulsations of the chest or back) that correspond to the main beat frequency f0. Similarly, the second corrected beat frequency intensity distribution D2' shows that second minor beat frequency components Fl2 and Rf2 are present in a region shifted from the main beat frequency f0. The second minor beat frequency component Fl2 includes beat frequency components lower in frequency than the main beat frequency f0, and the second minor beat frequency component Fh2 includes beat frequency components higher in frequency than the main beat frequency f0. The second sub beat frequency components Fl2 and Fh2 include beat frequency components corresponding to the movement of a part of the occupant M's body (a part other than the main body) (for example, pulsation of the chest or back).

[0045] The differential beat frequency intensity distribution D3 is data indicating the difference between the first corrected beat frequency intensity distribution D1' and the second corrected beat frequency intensity distribution D2'. The differential beat frequency intensity distribution D3 illustrated here is obtained by subtracting the second corrected beat frequency intensity distribution D2' from the first corrected beat frequency intensity distribution D1'.

[0046] As shown in the differential beat frequency intensity distribution D3, by taking the difference between the first corrected beat frequency intensity distribution D1' and the second corrected beat frequency intensity distribution D2', the main beat frequency components including the main beat frequency f0 are removed, leaving the sub beat frequency components F1 and Fh. In this example, the low-frequency sub beat frequency component F1 is obtained by subtracting the low-frequency second sub beat frequency component F12 from the low-frequency first sub beat frequency component F11, and the high-frequency sub beat frequency component Fh is obtained by subtracting the high-frequency second sub beat frequency component Fh2 from the high-frequency first sub beat frequency component Fh1.

[0047] By the above-described processing, it is possible to remove the main beat frequency components including the main beat frequency f0 corresponding to the overall movement of the occupant M, and extract the sub-beat frequency components Fl and Fh corresponding to the pulsation of a part of the body of the occupant M. At this time, the beat frequency components corresponding to the movement of the occupant M caused by the vibration of the vehicle C are removed together with the main beat frequency component. Therefore, the sub-beat frequency components Fl and Fh become information in which the influence of the vibration of the vehicle C has been reduced.

[0048] 6 is a diagram showing another example of the secondary beat frequency component according to the embodiment. The secondary beat frequency component Fs in this example is composed of beat frequency components equal to or higher than the reference frequency f3, which is higher than the main beat frequency f0 by a predetermined frequency, among the secondary beat frequency components F1 and Fh calculated as described above.

[0049] The detection accuracy of the object speed varies depending on the resolution of the LiDAR sensor 2. When the resolution of the LiDAR sensor 2 is low, the detection accuracy for slow movement, i.e., when the beat frequency is low, decreases. Therefore, by using the sub-beat frequency component Fs in a relatively high frequency range as in this example, high detection accuracy can be achieved even when using a LiDAR sensor 2 with a relatively low resolution.

[0050] 7 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 LiDAR 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).

[0051] 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 secondary speed information generation unit 324 generates secondary speed information 334 indicating a speed corresponding to the movement of a part of the body of the occupant M, including pulsation (S105). The biometric information generation unit 325 generates biometric information based on the secondary speed information (S106).

[0052] According to the above embodiment, the biological information of the occupant M is generated based on the secondary speed information based on the secondary beat frequency components Fl, Fh, and Fs from which the vibration components of the vehicle C have been removed. This makes it possible to detect the biological information of the occupant M of a moving body that generates vibrations, such as the vehicle C, with high accuracy.

[0053] 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.

[0054] 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]

[0055] 1...biometric information detection device, 2...LiDAR sensor, 3...control device, 21...transmitter, 22...receiver, 31...ADC, 32...processor, 33...storage unit, 321...position information generator, 322...speed information generator, 323...person detector, 324...sub-speed information generator, 325...biometric information generator, 331...setting information, 332...position information, 333...speed information, 334...sub-speed information, 335...biometric information, C...vehicle, D...labeling area, D1...first beat frequency intensity distribution, D2...second beat frequency intensity intensity distribution, D1'...first corrected beat frequency intensity distribution, D2'...second corrected beat frequency intensity distribution, D3...differential beat frequency intensity distribution, f0...main beat frequency, f1...first main beat frequency, f2...second main beat frequency, f3...reference frequency, Fl, Fh, Fs...sub-beat frequency components, Fl1, Fh1...first sub-beat frequency component, Fl2, Fh2...second sub-beat frequency component, M...occupant, P1, P2...maximum peak, S...seat, T...chirp period, T1...up period, T2...down period

Claims

1. a sensor that transmits a frequency-modulated laser beam as a transmission wave into a room of the mobile body and receives a reflected wave that is 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 sub-speed information generating unit that generates sub-speed information indicating a speed corresponding to a movement of a part of the person's body based on a sub-beat frequency component that does not include a main beat frequency corresponding to a maximum peak in a beat frequency intensity distribution that indicates a relationship between a beat frequency based on a difference between a frequency of the transmitted wave and a frequency of the reflected wave and an intensity of the reflected wave; a biometric information generating unit that generates biometric information of the person based on the sub-speed information; A biological information detection device comprising:

2. The sub-speed information generating unit generating a first beat frequency intensity distribution, which is the beat frequency intensity distribution based on a first transmission wave whose frequency increases over time and a first reflected wave generated when the first transmission wave is reflected by the object, and a second beat frequency intensity distribution, which is the beat frequency intensity distribution based on a second transmission wave whose frequency decreases over time and a second reflected wave generated when the second transmission wave is reflected by the object; calculating a Doppler frequency based on a first main beat frequency corresponding to a maximum peak in the first beat frequency intensity distribution and a second main beat frequency corresponding to a maximum peak in the second beat frequency intensity distribution; extracting the sub beat frequency component from a difference between a first corrected beat frequency intensity distribution obtained by correcting the first beat frequency intensity distribution based on the Doppler frequency and a second corrected beat frequency intensity distribution obtained by correcting the second beat frequency intensity distribution based on the Doppler frequency. The biological information detection device according to claim 1 .

3. the sub beat frequency component is composed of beat frequencies equal to or higher than a reference frequency that is higher by a predetermined frequency than the main beat frequency; The biological information detection device according to claim 1 or 2.

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