Living body detection device and living body detection method

Abstract

A living body detection device (10) comprises a speaker (SPU), a sound field control unit (30), a microphone (MIC), a sound pickup signal storage unit (40), and a sound field analysis unit (50). The sound field control unit (30) controls the directivity of sound emitted from the speaker (SPU), thereby controlling a sound field with respect to a detection target region of a living body. The microphone (MIC) collects the sound for the detection target region and generates a sound collection signal. The sound pickup signal storage unit (40) samples and stores the sound pickup signal at a plurality of times. The sound field analysis unit (50) detects a change in the sound field on the basis of a change in the sound collection signal at the plurality of times, and detects the status of the living body, including at least whether the living body is present, from the change in the sound field.

Description

Living body detection device and living body detection method

[0001] The present invention relates to a living body detection technology for detecting a person or the like left behind in a vehicle.

[0002] The device described in Patent Document 1 includes a plurality of speakers and a plurality of microphones, which are arranged at predetermined positions relative to a sound field in which a person is to be detected.

[0003] The plurality of speakers emits measurement sounds into the sound field.

[0004] The plurality of microphones collects the measurement sound from the sound field. The plurality of microphones are capable of changing the sound collection directivity, and collects the sound while changing the sound collection directivity.

[0005] The device described in Patent Document 1 detects the presence, position, etc. of a person in a sound field based on the results of sound pickup by a plurality of microphones.

[0006] Patent No. 4349972 specification

[0007] However, a configuration such as that of the device described in Patent Document 1 only collects sound from a target direction as sound collection directionality, and therefore the collected sound includes, for example, sound reflected by the walls of the vehicle, making it difficult to accurately determine whether a target object, such as a person, is in the sound collection direction.

[0008] Therefore, an object of the present invention is to provide a living body detection device that can more accurately detect the presence or absence of a living body in a detection target area and its location.

[0009] A living body detection device according to one embodiment of the present invention includes a speaker, a sound field control unit, a microphone, a sound collection signal storage unit, and a sound field analysis unit. The sound field control unit controls the sound field relative to a detection target area for a living body by controlling the directionality of sound emitted from the speaker. The microphone collects sound relative to the detection target area and generates a collected sound signal. The sound collection signal storage unit samples and stores the collected sound signal at multiple times. The sound field analysis unit detects changes in the sound field based on changes in the collected sound signal at multiple times, and detects the status of the living body, including at least the presence or absence of a living body, from the changes in the sound field.

[0010] In this configuration, sound is emitted intensively at the detection position within the detection target area where the condition of the living organism is to be investigated. As a result, the microphone's pickup signal is composed only of sound signals reflected at the detection position, which reflects the condition of the detection position, i.e., is a signal that is highly dependent on the living organism's condition. Therefore, changes in the sound field based on the pickup signal more reliably reflect changes in the living organism's condition at the detection position. As a result, by using these sound field changes, the living organism detection device can accurately detect whether there has been a change or not in the living organism's condition (e.g., whether the organism has been abandoned).

[0011] According to this invention, it is possible to more accurately detect the presence or absence of a living organism in a detection target area and its location.

[0012] FIG. 1 is a functional block diagram showing an example of a living body detection device according to a first embodiment. FIG. 2 is a diagram showing an example of the hardware configuration of the living body detection device according to the first embodiment. FIG. 3 is a diagram showing a schematic configuration of a bus to which an abandoned body detection system using a living body detection device is applied. FIG. 4(A) is an external perspective view of a sound emission and collection unit, FIG. 4(B) is a side view of the sound emission and collection unit, and FIG. 4(C) is a diagram showing an example of the arrangement of multiple speaker elements and microphones in the sound emission and collection unit. FIG. 5 is a table showing an example of the relationship between the state of a living body and frequency sound pressure distribution. FIG. 6 is a system flowchart showing an example of a living body detection method according to the first embodiment. FIG. 7 is a flowchart showing an example of processing by each functional unit of the living body detection device. FIG. 8 is a flowchart showing a specific example of sound field analysis. FIG. 9 is a functional block diagram showing an example of a living body detection device according to a second embodiment. FIG. 10 is a functional block diagram showing an example of a living body detection device according to a third embodiment. FIG. 11 is a diagram showing another example of the arrangement of speakers and microphones in the living body detection device. FIG. 12 is a diagram showing an example of another arrangement of a speaker and a microphone in a living body detection device.

[0013] [First embodiment] (Configuration of a living body detection device) A living body detection device according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a functional block diagram showing an example of a living body detection device according to the first embodiment.

[0014] As shown in FIG. 1, the biological detection device 10 includes a speaker SPU, a microphone MIC, a main control unit 20, a sound field control unit 30, a picked-up signal storage unit 40, a sound field analysis unit 50, a warning control unit 61, a communication unit 62, and an antenna ANT.

[0015] The speaker SPU is composed of a plurality of speaker elements SP1, SP2, SP3, and SP4. The number of speaker elements constituting the speaker SPU is not limited to four, but may be any plural number. The plurality of speaker elements SP1, SP2, SP3, and SP4 are, for example, omnidirectional.

[0016] The main control unit 20 issues various commands to operate other functional units that make up the biological detection device 10 .

[0017] The sound field control unit 30 receives a sound emission control command from the main control unit 20 and performs sound emission control, including directivity control, for the multiple speaker elements SP1, SP2, SP3, and SP4 of the speaker SPU. As sound emission control, the sound field control unit 30 sets the frequency of the sound to be emitted from each of the multiple speaker elements SP1, SP2, SP3, and SP4 and performs phase control. The sound field control unit 30 outputs a sound emission signal (electrical signal) of a predetermined frequency and phase-controlled to each of the multiple speaker elements SP1, SP2, SP3, and SP4. Note that the frequency of the sound output from the multiple speaker elements includes 10 to 100 Hz, and preferably includes an ultrasonic frequency.

[0018] Based on the sound emission signal from the sound field control unit 30, the multiple speaker elements SP1, SP2, SP3, and SP4 emit sounds (transmit sound waves) of a predetermined frequency into the area to be detected for the living body (for example, inside a bus where abandoned body detection is performed, as described below).

[0019] As a result, the sound field control unit 30 controls the directionality of the emitted sound (sound emission directionality) and controls it to form a predetermined sound field from the speaker SPU to the area where the living body is to be detected (for example, inside a bus where abandoned body detection is performed, as described below).

[0020] The microphone MIC has, for example, omnidirectional or wide-angle unidirectional characteristics. The microphone MIC collects sound (receives sound waves) from a detection target area of ​​a living body and generates a collected sound signal (electrical signal). The microphone MIC outputs the collected sound signal to the collected sound signal storage unit 40.

[0021] The sound collection signal storage unit 40 samples and stores the sound collection signal at a predetermined period based on a sound collection signal generation command from the main control unit 20. At this time, the sound collection signal storage unit 40 stores the sampling timing (sound collection time) of the sound collection signal in association with the sound collection signal.

[0022] The sound field analysis unit 50 performs sound field analysis based on sound signals collected at multiple sound collection times. In general terms, the sound field analysis unit 50 detects changes in the sound field based on changes in the sound signals collected at multiple times. The sound field analysis unit 50 detects the status of a living organism within a detection target area from the changes in the sound field. The status of a living organism within a detection target area includes at least the presence or absence of a living organism within the detection target area.

[0023] For example, the sound field analysis unit 50 detects the situation in which a child (living body) is left behind on a bus (detection target area).

[0024] The sound field analysis unit 50 outputs the detection result to the main control unit 20 .

[0025] If the main control unit 20 determines based on the detection result that a warning is necessary, it issues a warning notification command to the warning control unit 61 .

[0026] When the warning control unit 61 receives the warning notification command, it outputs warning information to the communication unit 62. The communication unit 62 transmits the warning information via the antenna ANT to, for example, a manager of the detection target area.

[0027] Such functions of the living body detection device 10 can be realized by a hardware configuration as shown in Fig. 2. Fig. 2 is a diagram showing an example of the hardware configuration of the living body detection device according to the first embodiment.

[0028] As shown in Fig. 2, the biological detection device 10 includes a main board MB, a power supply PW, a speaker SPU, a microphone MIC, and an antenna ANT. The main board MB includes a data bus line BUS, a CPU, a memory, a recording medium, a speaker IF, a microphone IF, and a communication IF. The main board MB configures the main control unit 20, sound field control unit 30, sound signal storage unit 40, sound field analysis unit 50, warning control unit 61, and communication unit 62 shown in Fig. 1. While an example in which all control units are configured on a single main board MB has been shown here, if the speaker SPU and microphone MIC are installed separately, boards with similar functions to the main board may be formed for each, and control may be assigned to each.

[0029] (Example of Specific Application of the Living Body Detection Device 10) FIG. 3 is a diagram showing a schematic configuration of a bus to which an abandoned person detection system using a living body detection device is applied.

[0030] As shown in FIG. 3 , the living body detection device 10 is mounted on a bus body 90. The body 90 corresponds to the "housing" of the present invention. The housing refers to a box-like body that encloses a detection target area and creates a closed space. The body 90 is a housing that includes a ceiling UW and has an interior space RE90. The interior space RE90 corresponds to the "detection target area." For example, multiple people HMN1, HMN2, and HMN3 are sitting (present) in predetermined positions in the interior space RE90. Note that the number and positions of people sitting in the interior space RE90 are not limited to those shown in FIG. 3 . Furthermore, while it is ideal for the housing to be a closed space so that sound is reflected, there may be some areas of the bus body that are not closed spaces, such as when a window is slightly open.

[0031] A sound emitting and collecting unit SMU is installed on the ceiling UW of the vehicle body 90.

[0032] Fig. 4A is a perspective view of the appearance of the sound emitting and collecting unit, Fig. 4B is a side view of the sound emitting and collecting unit, and Fig. 4C is a diagram showing an example of the arrangement of multiple speaker elements and microphones in the sound emitting and collecting unit.

[0033] As shown in FIGS. 4A and 4B, the sound emitting and collecting unit SMU includes a unit housing 81, a plurality of speaker elements SP1, SP2, SP3, and SP4, and a microphone MIC.

[0034] The unit housing 81 is cylindrical. The unit housing 81 has a mounting surface FS and a front end surface FD that face each other, and has a side surface that connects the mounting surface FS and the front end surface FD. The front end surface FD of the unit housing 81 is provided with a plurality of holes that allow sound to pass through.

[0035] A plurality of speaker elements SP1, SP2, SP3, and SP4 and a microphone MIC are disposed in holes provided on the FD surface at the tip. The microphone MIC is disposed at the center of the tip surface FD in a planar view. The plurality of speaker elements SP1, SP2, SP3, and SP4 are disposed at equal intervals on a circumference centered on the position of the microphone MIC in a planar view of the tip surface FD. Note that the arrangement of the plurality of speaker elements SP1, SP2, SP3, and SP4 and the microphone MIC is not limited to this. While FIG. 4 shows an example in which the microphone MIC and the speaker SP are flush with the tip surface FD, the microphone MIC and the speaker SP may protrude outward from the tip surface FD. This allows sound to be emitted with controlled sound emission directionality over a wide range.

[0036] The unit housing 81 is attached to the vehicle body 90 so that the installation surface FS abuts against the ceiling UW of the vehicle body 90. In this case, the unit housing 81 is disposed near the center in the fore-and-aft direction of the vehicle body 90. Note that the position at which the unit housing 81 is disposed is not limited to this, and it may be any position, such as above the front of the vehicle body 90, where a sound emission beam (details will be described later) can be formed toward the interior space RE90 (detection target area) and sound can be collected from the interior space RE90 (detection target area).

[0037] In this configuration, the plurality of speaker elements SP1, SP2, SP3, and SP4 emit sound from the front end face FD toward the outside of the unit housing 81. The microphone MIC collects sound from the front end face FD.

[0038] Then, multiple sound emission beams can be formed by directivity control in the sound emission control by the sound field control unit 30. The multiple sound emission beams are formed at different timings within a predetermined time range (a time range that can be considered to be the same timing in detecting the state of a living body). The multiple sound emission beams include, for example, multiple sound emission beams SB1, SB2, and SB3 shown in FIG. 3, and are formed with narrow directivity with the direction of each target position set differently as the center of directivity. The multiple sound emission beams are formed so that the distribution of each target position covers substantially the entire interior space RE90. This can be achieved, for example, by parametric speaker technology or sound emission beam forming.

[0039] The plurality of sound emission beams are formed at different timings by sound emission control by the sound field control unit 30. Furthermore, each of the plurality of sound emission beams is formed by sound waves of a plurality of frequencies.

[0040] For example, referring to FIG. 3, specifically, in the case of a plurality of sound emission beams SB1, SB2, and SB3, sound emission control is performed as follows.

[0041] A sound beam SB1 is formed for a predetermined time from timing ta. At this time, the sound beam SB1 is formed while switching between a plurality of frequencies.

[0042] Next, a sound emission beam SB2 is formed during a predetermined time from timing tb (≠ta). At this time, the sound emission beam SB2 is formed while switching between a plurality of frequencies, similar to the sound emission beam SB1.

[0043] Next, a sound emission beam SB3 is formed during a predetermined time from timing tc (≠ta, tb). At this time, the sound emission beam SB3 is formed while switching between a plurality of frequencies, similar to the sound emission beams SB1 and SB2.

[0044] The microphone MIC collects sounds reflected by the multiple sound emission beams at target positions in the vehicle interior space RE90 and outputs the collected sound signals to the collected sound signal storage unit 40.

[0045] The sound collection signal storage unit 40 stores the sound collection signals for the plurality of sound emitting beams as individual sound collection signals based on a sound collection signal generation command from the main control unit 20. Furthermore, the sound collection signal storage unit 40 stores the sound emitting beams of multiple frequencies in one sound emitting beam as individual sound collection signals.

[0046] With such a configuration and control, the living body detection device 10 forms sound emitting beams each having a plurality of frequency components for a plurality of target positions in the vehicle interior space RE90. Then, the living body detection device 10 stores the sound collection signals corresponding to each sound emitting beam.

[0047] At this time, the collected sound signal storage unit 40 samples and stores the collected sound signal at a plurality of times.

[0048] The sound field analysis unit 50 performs sound field analysis of the multiple target positions using the sound pickup signals for the multiple target positions. More specifically, the sound field analysis unit 50 calculates the relationship between frequency and sound pressure for each of the multiple target positions. In this case, the sound field analysis unit 50 calculates the relationship between frequency and sound pressure at multiple times. This relationship between frequency and sound pressure at multiple times is the frequency sound pressure distribution at the target position.

[0049] The sound field analysis unit 50 detects the state of the living body at the target position based on the frequency sound pressure distribution. At this time, the sound field analysis unit 50 detects the state of the living body by estimation using machine learning based on the frequency sound pressure distribution.

[0050] Specifically, the sound field analysis unit 50 stores, as reference information through prior machine learning, the relationship between the state of a living body and the frequency sound pressure distribution as shown in Fig. 5. Fig. 5 is a table showing an example of the relationship between the state of a living body and the frequency sound pressure distribution.

[0051] For example, as shown in Fig. 5, a frequency sound pressure distribution "PT0" is associated with and stored as the biological situation "no one present," and a frequency sound pressure distribution "PT1" is associated with and stored as the biological situation "adults present." A frequency sound pressure distribution "PT2" is associated with and stored as the biological situation "children present," and a frequency sound pressure distribution "PT3" is associated with and stored as the biological situation "small animals present." Note that the difference between "adults" and "children" here is not based on age, but on, for example, the size and shape of the body, the magnitude and speed of movement, etc.

[0052] The sound field analysis unit 50 estimates the state of the living body from the relationship between the state of the living body and the frequency sound pressure distribution for each of the frequency sound pressure distributions at multiple times. For example, the sound field analysis unit 50 estimates that a child is present if the frequency sound pressure distribution is PT2. The sound field analysis unit 50 estimates that no one is present if the frequency sound pressure distribution is PT0.

[0053] The sound field analysis unit 50 detects whether the state of the living body has changed at multiple times. For example, if there is a change from the frequency sound pressure distribution PT2 to the frequency sound pressure distribution PT0, the sound field analysis unit 50 detects that the state has changed from one in which a child was present to one in which no one was present. Furthermore, if the frequency sound pressure distribution PT2 continues at multiple times, the sound field analysis unit 50 detects that the state is one in which a child continues to be present.

[0054] The sound field analysis unit 50 outputs the detection results of the living body conditions at the multiple target positions to the main control unit 20 .

[0055] The main control unit 20 determines whether a situation requiring a warning, such as abandonment (a dangerous situation), has occurred based on the detection results of the biological status at multiple target positions. For example, when the main control unit 20 detects that a child has been continuously present for a predetermined period of time (child abandonment) under predetermined conditions (for example, when the car engine is stopped and the car is parked), it determines that a situation requiring a warning is one in which a warning is necessary. Note that the situation requiring a warning is not limited to this, and can be set as appropriate.

[0056] If a situation requires a warning, the main control unit 20 generates a warning notification command. At this time, it is preferable that the main control unit 20 generates the warning notification command depending on the type of situation requiring a warning. For example, if the main control unit 20 detects that a child has been left behind, it generates a warning notification command indicating that there is a possibility that a child has been left behind. The main control unit 20 notifies the warning control unit 61 of the warning notification command.

[0057] When the warning control unit 61 receives a warning notification command, it outputs warning information to the communication unit 62. For example, when the warning control unit 61 receives a warning notification command for a child being left behind, it outputs warning information for a child being left behind to the communication unit 62.

[0058] The communication unit 62 transmits the warning information via the antenna ANT. For example, the communication unit 62 transmits the warning information via the antenna ANT to a smartphone, car keys, or the like held by a manager of the detection target area. Note that the recipient of the warning information is not limited to a smartphone, but may also be a personal computer of a remote management company, or the like.

[0059] Furthermore, the communication unit 62 may control the turning on and off of various lights, hazard lights, and the like that emit light to the outside of the vehicle body 90, without using the antenna ANT. The communication unit 62 may also sound the horn of the vehicle body 90. In other words, the communication unit 62 may have any configuration as long as it can notify the outside of the vehicle body 90 of warning information.

[0060] With this configuration, the living body detection device 10 can notify people outside the vehicle body 90 of a possible danger occurring in the vehicle interior space RE90 (for example, a child being left behind).

[0061] In this case, the living body detection device 10 controls the sound emission directivity to form a sound emission beam and emits sound only at the position of the detection target. As a result, the sound picked up by the microphone MIC is composed almost entirely of sound reflected at the position of the detection target. Therefore, the living body detection device 10 can suppress the influence of noise within the vehicle interior space RE90 (such as reflected sound from the vehicle body 90) on the picked-up sound signal. In addition, since the picked-up sound signal largely reflects information about the detection position, it becomes easier to detect even slight changes, such as those caused by small children or small animals.

[0062] This allows the living body detection device 10 to more accurately detect the presence or absence of a living body in the detection target area and its location, and notify the outside.

[0063] In the above configuration, a danger warning is sent to the outside, but the communication unit 62 may also control the air conditioning of the vehicle body 90. For example, the communication unit 62 controls the air conditioning of the air conditioning equipment of the vehicle body 90 so as to maintain the temperature of the interior space RE90 within a predetermined appropriate temperature range for comfort.

[0064] In the above configuration, the speaker SPU uses one type of sound emission directivity, but it is also possible to set multiple types of sound emission directivity. For example, a first directivity and a second directivity that is narrower than the first directivity can be set, and the living body detection device 10 can switch between the first directivity and the second directivity.

[0065] As a result, for example, by using the first directivity, it is possible to detect the biological condition over a wide range and quickly detect the biological condition for the entire detection target area, whereas by using the second directivity, it is possible to detect the biological condition over a more limited range and more reliably detect the biological condition at the target position.

[0066] Furthermore, the microphone MIC is preferably a MEMS microphone, which allows the microphone MIC to be miniaturized, and for example, the sound emitting and collecting unit SMU to be miniaturized.

[0067] (Living Body Detection Method) Fig. 6 is a system flowchart showing an example of a living body detection method according to the first embodiment. Fig. 6 shows a flowchart of abandonment detection.

[0068] 6 is explained in the above configuration description, and only the parts that require specific explanation will be explained below. Also, FIG. 6 is a system flow, and will be explained using the living body detection device 10 as the subject.

[0069] The living body detection device 10 determines the start of operation (S11). The start of operation is determined, for example, by the vehicle body 90, which had been moving, coming to a stop, the engine being stopped, the doors of the vehicle body 90 being locked, etc.

[0070] The living body detection device 10 sets a sound field (sound emission directivity) for the interior space RE90 of the vehicle body 90 (S12). The living body detection device 10 emits sound into the interior space RE90 with the set sound emission directivity (S13).

[0071] The living body detection device 10 collects sound from the vehicle interior space RE90 and generates a collected sound signal (S14). The living body detection device 10 performs a sound field analysis based on the collected sound signal (S15).

[0072] The living body detection device 10 detects whether or not an object has been left behind at the target position based on the results of the sound field analysis. If there is no object left behind at the target position (S16: NO), the living body detection device 10 performs abandonment detection at other target positions. If abandonment detection has not been completed for the entire vehicle interior space RE90 (S19: NO), the living body detection device 10 continues the abandonment detection. If abandonment detection has been completed for the entire vehicle interior space RE90 (S19: YES), the living body detection device 10 ends abandonment detection.

[0073] If there is an abandoned person at the target position (S16: YES), the living body detection device 10 issues a warning to the outside (S17). If the living body detection device 10 does not receive input indicating that rescue is complete after the warning (S18: NO), it continues the warning. If the living body detection device 10 receives input indicating that rescue is complete after the warning (S18: YES), it ends the warning.

[0074] To realize this system flow, the main control unit 20, sound field control unit 30, collected sound signal storage unit 40, and sound field analysis unit 50 perform the processing shown in Fig. 7. Fig. 7 is a flowchart showing an example of the processing of each functional unit of the living body detection device. Below, we will explain the control and processing flow roughly along the multiple flowcharts.

[0075] When the operation start trigger is turned ON (S21: YES), the main control unit 20 issues a sound emission control command to the sound field control unit 30 (S22). The operation start trigger is turned ON based on the criteria shown in step S11 of Fig. 6. For example, the operation start trigger is turned ON when the vehicle body 90, which had been moving, stops, the engine is stopped, and the doors of the vehicle body 90 are locked.

[0076] The main control unit 20 issues a sound emission control command to the sound field control unit 30 and a sound pickup signal generation command to the sound pickup signal storage unit 40 at substantially the same time (S23).

[0077] When the sound field control unit 30 receives the sound emission control command (S31: YES), it performs sound emission control so as to realize the sound emission directivity instructed by the sound emission control command (S32).

[0078] When the collected sound signal storage unit 40 receives the collected sound signal generation command (S41: YES), it stores the collected sound signal for a period designated by the collected sound signal generation command (S42).

[0079] The sound field analysis unit 50 acquires a picked-up sound signal (S51) and performs a sound field analysis (S52). The sound field analysis is performed upon receiving a command from the main control unit 20 to perform the sound field analysis.

[0080] The sound field analysis unit 50 detects the state of the living body from the result of the sound field analysis (S53), and outputs the detection result to the main control unit 20 (S54).

[0081] 8 is a flowchart showing a specific example of sound field analysis. As shown in FIG. 8, the sound field analysis unit 50 acquires a picked-up sound signal (S51). The sound field analysis unit 50 generates a frequency sound pressure distribution (S521). The sound field analysis unit 50 compares the generated frequency sound pressure distribution with a reference frequency sound pressure obtained by machine learning to estimate the condition of the living body (S522).

[0082] The sound field analysis unit 50 compares the current estimation result with the previous estimation result (S531). If there is a change in the living body's condition (S532: YES), the sound field analysis unit 50 outputs the result of the condition change (S54). If there is no change in the living body's condition (S532: NO), the sound field analysis unit 50 ends the process.

[0083] The main control unit 20 acquires the detection result of the state of the living body based on the sound field analysis result (S24). If the detection result does not require a warning (S25: NO), the main control unit 20 repeats the above-mentioned sound emission control and sound collection signal generation control.

[0084] If the detection result indicates that a warning is required (S25: YES), the main control unit 20 generates a warning notification command (S26). Warning information based on the warning notification command is notified to the outside.

[0085] The main control unit 20 repeats generating the warning notification command until it detects that the warning has been cancelled (S27: NO). The cancellation of the warning can be detected based on the receipt of a rescue completion notification from the outside or the detection result of the condition of the living body based on the subsequent sound field analysis result.

[0086] When the main control unit 20 detects that the warning has been cancelled (S27: YES), it ends the warning and terminates all control.

[0087] Second Embodiment A living body detection device according to a second embodiment of the present invention will be described with reference to Fig. 9. Fig. 9 is a functional block diagram showing an example of a living body detection device according to the second embodiment.

[0088] 9, the living body detection device 10A according to the second embodiment differs from the living body detection device 10 according to the first embodiment in the configuration of the speaker SPUA. Other configurations of the living body detection device 10A are the same as those of the living body detection device 10, and a description of similar parts will be omitted.

[0089] The living body detection device 10A includes a speaker SPUA. The speaker SPUA includes a speaker element SP1 and a position change mechanism SPM. The speaker element SP1 has the same configuration as the speaker element SP1 according to the first embodiment.

[0090] The attitude change mechanism SPM is a drive mechanism that physically changes the attitude of the speaker element SP1.

[0091] The sound field control unit 30A controls the attitude change mechanism SPM based on the sound emission control command to change the direction of the center of the directivity of the speaker element SP1. In other words, the sound field control unit 30A uses the attitude change mechanism SPM to physically pan the speaker element SP1 based on the sound emission control command, thereby panning the direction of the center of the directivity of the speaker element SP1.

[0092] With this configuration, the living body detection device 10A can achieve the same effects as the living body detection device 10.

[0093] Furthermore, even when it is difficult to form sound beams in multiple directions using multiple speaker elements, the living body detection device 10A can form sound beams in multiple directions by physical pan control.Furthermore, the living body detection device 10A can reduce the number of speaker elements.

[0094] [Third Embodiment] A living body detection device according to a third embodiment of the present invention will be described with reference to Fig. 10. Fig. 10 is a functional block diagram showing an example of a living body detection device according to the third embodiment.

[0095] 10, the living body detection device 10B according to the third embodiment differs from the living body detection device 10 according to the first embodiment in that it includes multiple microphones and in the configuration of a collected signal storage unit 40B. The other configuration of the living body detection device 10B is the same as that of the living body detection device 10, and a description of similar parts will be omitted.

[0096] The living body detection device 10B includes a plurality of microphones MIC1, MIC2, and MIC3, and a collected signal storage unit 40B. The plurality of microphones MIC1, MIC2, and MIC3 in this embodiment correspond to the "microphone elements" in certain claims of the present invention, and the assembly (microphone array) formed by these plurality of microphones MIC1, MIC2, and MIC3 corresponds to the "microphone" in certain claims of the present invention.

[0097] The plurality of microphones MIC1, MIC2, and MIC3 form a microphone array arranged in a predetermined pattern.

[0098] The collected sound signal storage unit 40B performs micro beam forming by performing phase control (delay control) on the collected sound signals of the multiple microphones MIC1, MIC2, and MIC3. The collected sound signal storage unit 40B stores the collected sound signals that have been subjected to micro beam forming. In other words, the collected sound signal storage unit 40B has the function of a "sound collection control unit."

[0099] With this configuration, the living body detection device 10B can achieve the same effects as the living body detection device 10.

[0100] Furthermore, by using both a sound emission beam and a sound collection beam, the living body detection device 10B can emit sound only at the target position and collect sound only from the target position, thereby enabling the living body detection device 10B to more reliably detect the condition of the living body at the target position.

[0101] [Alternative 1 of Speaker and Microphone Arrangement Pattern] Fig. 11 is a diagram showing an example of an alternative arrangement of speakers and microphones in a living body detection device. In the arrangement shown in Fig. 11, multiple speaker elements SP1, SP2, SP3, and SP4 of a speaker SPU are arranged on the ceiling UW of a vehicle body 90. Multiple microphones MU are arranged on a left wall SWR and a right wall SWL of the vehicle body 90, respectively. The microphone MU may be a single microphone or a microphone array of multiple microphones.

[0102] With this configuration, the living body detection device arranged as shown in FIG. 11 can achieve the same effects as the living body detection device 10.

[0103] Furthermore, by placing the microphones MU on the left and right side walls, blind spots in sound pickup can be reduced, allowing the living body detection device to more thoroughly detect living bodies throughout the entire vehicle interior space RE90 (detection target area).

[0104] [Alternative 2 of Speaker and Microphone Arrangement Pattern] Fig. 12 is a diagram showing an example of an alternative arrangement of speakers and microphones in a living body detection device. The arrangement shown in Fig. 12 includes a plurality of sound emitting and collecting units SMUR and SMUL.

[0105] The sound emitting and collecting unit SMUR is disposed on the left side wall SWR of the vehicle body 90. The sound emitting and collecting unit SMUL is disposed on the right side wall SWL of the vehicle body 90.

[0106] With this configuration, the living body detection device arranged as shown in FIG. 12 can achieve the same effects as the living body detection device 10.

[0107] Furthermore, by arranging multiple sound emitting and collecting units SMUR and SMUL on each of the left and right side walls, it is possible to reduce blind spots in the sound emitting and collecting, thereby enabling the living body detection device to more thoroughly detect living bodies throughout the entire vehicle interior space RE90 (detection target area).

[0108] Furthermore, the speaker element of the sound emitting and collecting unit SMUR is paired with a microphone, and the speaker element of the sound emitting and collecting unit SMUL is paired with a microphone. Then, each sound emitting and collecting unit SMUR and SMUL are individually controlled. As a result, the biological control device can more reliably detect the position of the target biological body, for example, by using the time difference between the sound collection signals of each sound emitting and collecting unit SMUR and SMUL.

[0109] The configurations and various aspects of the above-described embodiments can be combined as appropriate, and effects according to each combination can be achieved.

[0110] <1> A living body detection device comprising: a speaker; a sound field control unit that controls the sound field for a detection target area of ​​a living body by controlling the directionality of sound emitted from the speaker; a microphone that collects sound for the detection target area and generates a collected sound signal; a collected sound signal storage unit that samples and stores the collected sound signal at multiple times; and a sound field analysis unit that detects a change in the sound field based on changes in the collected sound signal at the multiple times and detects the status of the living body including at least the presence or absence of the living body from the change in the sound field.

[0111] <2> The living body detection device according to <1>, wherein the speaker is composed of a plurality of speaker elements, and the sound field control unit controls the sound field by controlling the phase of sounds emitted by the plurality of speaker elements.

[0112] <3> The living body detection device described in <1> or <2>, wherein the speaker includes a single speaker element and a posture change mechanism that changes the posture of the speaker element, and the sound field control unit controls the sound field by physically changing the sound emission direction of the speaker element using the posture change mechanism.

[0113] <4> The living body detection device according to any one of <1> to <3>, wherein the speaker is arranged on a ceiling of a housing that defines the detection target area.

[0114] <5> The living body detection device according to any one of <1> to <4>, wherein the speaker emits a sound of a single frequency.

[0115] <6> The living body detection device according to any one of <1> to <4>, wherein the speaker emits sounds of a plurality of different frequencies.

[0116] <7> The living body detection device according to any one of <1> to <6>, wherein the speaker emits sound by switching between a first directivity and a second directivity that is narrower than the first directivity.

[0117] <8> The living body detection device according to any one of <1> to <7>, wherein the microphone is omnidirectional.

[0118] <9> The living body detection device according to any one of <1> to <8>, wherein the microphone is capable of adjusting sound collection directionality.

[0119] <10> The living body detection device according to any one of <1> to <9>, wherein the microphone is disposed on a ceiling of a housing that defines the detection target area.

[0120] <11> The living body detection device according to any one of <1> to <10>, wherein the microphone is disposed on a side surface of a housing that defines the detection target area.

[0121] <12> The sound field analysis unit performs machine learning in advance on the relationship between changes in the sound field based on changes in the sound pickup signal at multiple times and the state of the specific living body, and stores the data as reference data; and detects the state of the specific living body based on a comparison result between the acquired changes in the sound field and the reference data. The living body detection device described in any of <1> to <11>.

[0122] <13> The living body detection device according to any one of <1> to <12>, wherein the speaker and the microphone are paired in advance, and the sound field analysis unit detects the state of the living body based on sound emitted from the paired speaker and sound picked up by the microphone.

[0123] <14> The living body detection device according to any one of <1> to <13>, wherein the microphone is composed of a plurality of microphone elements arranged in a predetermined pattern, and the living body detection device further includes a sound collection control unit that controls sound collection of the plurality of microphone elements to perform microbeamforming and outputs a sound collection signal obtained by the microbeamforming.

[0124] <15> The biological detection device according to any one of <1> to <14>, wherein the microphone is a MEMS microphone.

[0125] DESCRIPTION OF SYMBOLS 10, 10A, 10B: Biological detection device 20: Main control unit 30, 30A: Sound field control unit 40, 40B: Sound collection signal storage unit 50: Sound field analysis unit 61: Warning control unit 62: Communication unit 81: Unit housing 90: Vehicle body ANT: Antenna BUS: Data bus line FD: Tip surface FS: Installation surface HMN1, HMN2, HMN3: Person MB: Main board MIC, MIC1, MIC2, MIC3: Microphone PW: Power supply RE90: Vehicle interior space SB1, SB2, SB3: Sound emission beam SMU, SMUL, SMUR: Sound emission and collection unit SP1, SP2, SP3, SP4: Speaker element SPU, SPUA: Speaker SWL: Right side wall SWR: Left side wall UW: Ceiling

Claims

1. A living body detection device comprising: a speaker; a sound field control unit that controls the sound field in a detection target area of ​​a living body by controlling the directionality of sound emitted from the speaker; a microphone that collects sound in the detection target area and generates a collected sound signal; a collected sound signal storage unit that samples and stores the collected sound signal at multiple times; and a sound field analysis unit that detects changes in the sound field based on changes in the collected sound signal at multiple times and detects the status of the living body including at least the presence or absence of the living body from the changes in the sound field.

2. The living body detection device according to claim 1, wherein the speaker is composed of a plurality of speaker elements, and the sound field control unit controls the sound field by controlling the phase of the sounds emitted by the plurality of speaker elements.

3. A biological detection device as described in claim 1 or claim 2, wherein the speaker comprises a single speaker element and an attitude change mechanism that changes the attitude of the speaker element, and the sound field control unit controls the sound field by physically changing the sound emission direction of the speaker element using the attitude change mechanism.

4. A living body detection device according to any one of claims 1 to 3, wherein the speaker is arranged on the ceiling of a housing that defines the detection target area.

5. A living body detection device according to any one of claims 1 to 4, wherein the speaker emits a sound of a single frequency.

6. A living body detection device according to any one of claims 1 to 4, wherein the speaker emits sounds of a plurality of different frequencies.

7. The living body detection device according to any one of claims 1 to 6, wherein the speaker emits sound by switching between a first directivity and a second directivity that is narrower than the first directivity.

8. A living body detection device according to any one of claims 1 to 7, wherein the microphone is omnidirectional.

9. A living body detection device according to any one of claims 1 to 8, wherein the microphone has adjustable sound pickup directionality.

10. A living body detection device according to any one of claims 1 to 9, wherein the microphone is arranged on the ceiling of a housing that defines the detection target area.

11. A living body detection device according to any one of claims 1 to 10, wherein the microphone is arranged on a side surface of a housing that defines the detection target area.

12. A living body detection device as described in any one of claims 1 to 11, wherein the sound field analysis unit performs machine learning in advance on the relationship between the change in the sound field based on the change in the sound signal picked up at multiple times and the state of the specific living body, and stores the result as reference data, and detects the state of the specific living body based on the result of comparing the acquired change in the sound field with the reference data.

13. A living body detection device according to any one of claims 1 to 12, wherein the speaker and the microphone are paired in advance, and the sound field analysis unit detects the state of the living body based on the sound emitted by the paired speaker and the sound picked up by the microphone.

14. A biological detection device according to any one of claims 1 to 13, wherein the microphone is composed of a plurality of microphone elements arranged in a predetermined pattern, and further comprising a sound collection control unit that controls the sound collection of the plurality of microphone elements to perform microbeamforming and outputs a sound collection signal obtained by the microbeamforming.

15. The biological detection device according to any one of claims 1 to 14, wherein the microphone is a MEMS microphone.

16. A living organism detection method comprising the steps of: controlling the sound field relative to a living organism detection area by controlling the directionality of sound emitted from a speaker; emitting sound from the speaker; collecting sound relative to the detection area and generating a collected sound signal; sampling and storing the collected sound signal at multiple times; detecting changes in the sound field based on changes in the collected sound signals at the multiple times, and detecting the status of the living organism, including at least the presence or absence of the living organism, from the changes in the sound field.

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