Living body sensing device, radio wave sensor, living body sensing system, and living body sensing method

Abstract

The present invention comprises: a sensor information acquisition unit (101) that acquires sensor information generated on the basis of reflected waves obtained when radio waves are reflected by an object within a chamber, the radio waves being emitted within the chamber by a radio wave sensor (10) toward an in-chamber region that includes at least a seat present within the chamber; and a sensing unit (104) that senses whether an object is present within the chamber, the sensing being carried out on the basis of sensor information, a first distance to a first target point that is present on an upper surface in a columnar target region having a height in a height direction of the seat serving as a target for sensing whether a living body is present on the basis of the sensor information from the position of the radio wave sensor (10) and that is located at the position closest to the position of the radio wave sensor (10), a second distance to a second target point that is present on the upper surface in the target region from the position of the radio wave sensor (10) and that is located at the position furthest from the position of the radio wave sensor (10) relative to the first target point, and a third distance to a third target point that is furthest from the second target point in the target region.

Description

Living body detection device, radio wave sensor, living body detection system, and living body detection method

[0001] The present disclosure relates to a living body detection device, a radio wave sensor, a living body detection system, and a living body detection method.

[0002] Conventionally, there has been known a technology for detecting a living organism present in a vehicle cabin based on information contained in a reflected wave received by a radio wave sensor that is installed in the vehicle cabin, radiates radio waves into the vehicle cabin, and receives reflected waves of the radiated radio waves reflected by the body surface. For example, Patent Document 1 discloses a technology for detecting a living organism present in a vehicle cabin based on information contained in the reflected wave received by a radio wave sensor that is installed in the vehicle cabin, radiates radio waves into the vehicle cabin, and receives reflected waves of the radiated radio waves reflected by the body surface (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2020-101415

[0004] When radio waves emitted from a radio wave sensor are irradiated onto a structure or the like in a room, the irradiated radio waves may be reflected depending on the material of the structure or the like. For example, if a living organism is present in a blind spot from the radio wave sensor, such as a location blocked by a structure or the like that reflects the radiated radio waves, the radio waves emitted from the radio wave sensor may not be directly reflected by the body surface of the living organism. Conventional technologies do not take this into consideration, and therefore still have the problem of being unable to detect a living organism present in a room.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a living body detection device capable of detecting a living body present in a room.

[0006] The living body detection device of the present disclosure includes a sensor information acquisition unit that acquires sensor information generated based on reflected waves from objects in the room of radio waves emitted by a radio wave sensor toward an indoor area including at least seats present in the room; and a detection unit that detects whether a living body is present in the room based on the sensor information acquired by the sensor information acquisition unit, a first distance from the position of the radio wave sensor to a first target point, which is a point on the top surface of a columnar target area having a height in the height direction of the seats that is the target for detecting the presence or absence of a living body based on the sensor information, and is the point closest to the position of the radio wave sensor, a second distance from the position of the radio wave sensor to a second target point, which is a point on the top surface of the target area and is the point farthest from the position of the radio wave sensor than the first target point, and a third distance from the second target point to a third target point, which is the point farthest from the second target point in the target area.

[0007] According to the present disclosure, it is possible to detect a living organism present in a room.

[0008] 5A, 5B, and 5C are diagrams illustrating an example in which a detection unit detects whether a living organism is present in a vehicle cabin based on whether the distance to an object detected by the radio wave sensor satisfies a first detection condition, in Embodiment 1. FIG. 5A is a diagram illustrating a radio wave sensor function equipped with a living organism detection device according to Embodiment 1. FIG. 5B is a diagram illustrating an example of a configuration of a living organism detection device according to Embodiment 1. FIG. 5C is a diagram illustrating an example in which a detection unit detects whether a living organism is present in a vehicle cabin based on whether the distance to an object detected by the radio wave sensor satisfies a first detection condition, in Embodiment 1. FIG. 5C is a flowchart illustrating the operation of a living organism detection device according to Embodiment 1. FIG. 5A is a diagram illustrating an example of a target area set by the area setting unit in a target area setting process when the area setting unit includes an area below the seat surface in the target area, in Embodiment 1. FIG. 5B is a diagram illustrating an example of how the radiation range of radio waves emitted from the transmitting antenna by the radio wave sensor is controlled, in Embodiment 1. FIG. 10A and FIG. 10B are diagrams illustrating an example of a configuration of a living organism detection system including a radio wave sensor and a living organism detection device according to Embodiment 1.

[0009] In order to explain the present disclosure in more detail, embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0010] Embodiment 1. A living body detection device according to embodiment 1 detects whether or not a living body is present in a room based on sensor information generated by a radio wave sensor. The radio wave sensor emits radio waves toward an area in the room that includes at least the seats present in the room (hereinafter referred to as the "indoor area"), receives reflected waves of the radio waves, detects objects present in the room based on the reflected waves, and generates sensor information. In embodiment 1, the seats are assumed to have backrests.

[0011] In the following first embodiment, as an example, the interior of a vehicle is assumed to be the interior of the vehicle. The radio wave sensor is installed in the vehicle interior, emits radio waves toward an interior area including at least the front or rear seats present in the vehicle interior, receives reflected waves of the radio waves, detects objects present in the vehicle interior, and generates sensor information. Specifically, "including the front or rear seats" refers to an area above the seat surface of the front seats and in front of the backrests of the front seats, including the headrests, or an area above the seat surface of the rear seats and in front of the backrests of the rear seats, including the headrests. The living body detection device detects whether an occupant is present in the vehicle interior based on the sensor information generated by the radio wave sensor. In the following first embodiment, the interior area of ​​the vehicle interior is referred to as the "interior area of ​​the vehicle interior." In the following first embodiment, a "rear seat" refers to a seat that has a seat in front of it. A "front seat" refers to a seat that does not have a seat in front of it. For example, if the vehicle has three rows of seats, then the vehicle has two rows of rear seats.

[0012] The living organisms detected by the living organism detection device according to the first embodiment include various living organisms such as humans, pets, etc. In the first embodiment, the living organism detection device detects a human occupant of a vehicle, for example. The occupant of the vehicle includes an infant in a child car seat.

[0013] The living body detection device 1 according to the first embodiment is mounted, for example, on a radio wave sensor 10. Fig. 1 is a diagram showing functions of the radio wave sensor 10 mounted with the living body detection device 1 according to the first embodiment. Fig. 2 is a diagram showing an example of the configuration of the living body detection device 1 according to the first embodiment.

[0014] The radio wave sensor 10 is mounted on a vehicle (not shown). In the first embodiment, the radio wave sensor 10 is assumed to be a millimeter-wave radar. The living body detection device 1 detects whether or not an occupant is present in the vehicle cabin based on sensor information generated by the radio wave sensor 10. The living body detection device 1 is connected to an abandonment detection device 200 and outputs a detection result indicating whether or not an occupant is present in the vehicle cabin to the abandonment detection device 200. The abandonment detection device 200 is mounted on, for example, a vehicle and outputs an alarm based on the detection result indicating whether or not an occupant is present in the vehicle cabin output from the living body detection device 1. The abandonment detection device 200 may be provided in a location outside the vehicle that can be accessed by the living body detection device 1, such as an external server (not shown).

[0015] FIG. 3 is a diagram illustrating an example of installation of the radio wave sensor 10 and radio waves emitted from the radio wave sensor 10 in the first embodiment. In FIG. 3, the vehicle is indicated by "100," the front seat is indicated by "S1," and the rear seat is indicated by "S2." FIG. 3 is a side view of the vehicle. A forward-facing child car seat (indicated by "CH" in FIG. 3) is installed in the rear seat of the vehicle interior, and an infant (indicated by "H" in FIG. 3) is seated in the child car seat. Note that while FIG. 3 shows the vehicle as a left-hand drive vehicle, this is merely an example, and the vehicle may also be a right-hand drive vehicle.

[0016] As shown in FIG. 3 , the radio wave sensor 10 is installed, for example, in the overhead console of a vehicle. It emits radio waves toward the interior of the vehicle and receives reflected waves from objects within the vehicle. As shown in FIG. 3 , the radio waves emitted from the radio wave sensor 10 installed in the overhead console reach the interior area in front of the front seat backs directly, but do not reach the interior area in front of the rear seat backs because the front seats act as a shield. In other words, the radio wave sensor 10 cannot see the interior area in front of the rear seat backs. The radio waves emitted from the radio wave sensor 10 reach the interior area in front of the rear seat backs only after being reflected by interior structures such as the ceiling or seat headrests (hereinafter referred to as “interior structures”). In other words, the radio waves emitted from the radio wave sensor 10 are not directly irradiated onto the occupant (here, an infant), but are instead reflected by interior structures and then irradiated onto the occupant. The living body detection device 1 of embodiment 1 is thus capable of detecting occupants in the vehicle cabin by taking advantage of the phenomenon in which radio waves from the radio wave sensor 10 are reflected by structures inside the vehicle cabin and irradiated onto the occupants, even when the radio waves emitted from the radio wave sensor 10 are not directly irradiated onto the occupants, in other words, even when the radio wave sensor 10 cannot directly see the occupants.

[0017] Although FIG. 3 does not show an occupant seated in the front seat, the radio waves emitted from the radio wave sensor 10 do not necessarily reach the occupant seated in the front seat even in the interior area in front of the front seat. For example, if a rearward-facing child car seat is installed in the front seat and an infant is riding in the child car seat, the child car seat may act as a shield, preventing the radio waves emitted from the radio wave sensor 10 from directly reaching the infant. However, even in this case, the radio waves from the radio wave sensor 10 may be reflected by interior structures and the like before reaching the infant. The living body detection device 1 according to the first embodiment can detect an occupant in the vehicle cabin even in such a case by utilizing the phenomenon in which the radio waves from the radio wave sensor 10 are reflected by interior structures and the like and then irradiated toward the occupant.

[0018] In the following first embodiment, the interior area of ​​the vehicle is the entire space within the vehicle, and it is assumed that the radio wave sensor 10 is installed in the overhead console of the vehicle, as shown in FIG. 3 . Note that this is merely an example, and the interior area of ​​the vehicle may be, for example, an area within the vehicle that does not include the front seats but includes the rear seats. Furthermore, the radio wave sensor 10 is not limited to being installed in the overhead console of the vehicle. For example, the radio wave sensor 10 may be installed on the ceiling of the vehicle or on the dashboard. The radio wave sensor 10 may be installed so as to be able to irradiate radio waves toward the interior area of ​​the vehicle.

[0019] 1, the function of the radio wave sensor 10 will be described. The transmitting antenna Tx is a planar antenna configured on an electronic circuit board. The transmitting antenna Tx has one or more transmitting antenna elements that radiate radio waves toward the interior of the vehicle cabin.

[0020] The installation positions of the transmitting antenna elements are different from each other in the vehicle height direction.

[0021] The receiving antenna Rx is a planar antenna configured on an electronic circuit board and is installed on the same plane as the transmitting antenna Tx. However, the same plane here does not mean that the plane on which the transmitting antenna Tx and the plane on which the receiving antenna Rx are installed are strictly the same, but also includes different planes as long as there are no practical problems. The receiving antenna Rx has one or more receiving antenna elements that receive reflected waves of the radio waves emitted from the transmitting antenna Tx.

[0022] The receiving antenna elements are installed at different positions in the width direction of the vehicle.

[0023] The radio wave sensor circuit 13 includes a high-frequency signal generating circuit 14, a radio wave transmitting unit 15, a radio wave receiving unit 16, an analog-to-digital conversion circuit (hereinafter referred to as "A / D conversion circuit") 17, a signal processing unit 18, and the living body detection device 1. The high-frequency signal generating circuit 14, the radio wave transmitting unit 15, and the radio wave receiving unit 16 constitute a radio wave transmitting / receiving unit 19 that emits radio waves from the transmitting antenna Tx and acquires a received signal based on the reflected waves from the receiving antenna Rx.

[0024] The high-frequency signal generating circuit 14 generates an FM (Frequency Modulation) signal, whose frequency changes over time, as a sensing signal and outputs the FM signal to the radio wave transmitting unit 15 and the radio wave receiving unit 16. In the radio wave sensor 10 shown in FIG. 1 , the FM-CW (Frequency Modulation-Continuous Wave) method is used as the modulation method, and the high-frequency signal generating circuit 14 generates the FM signal. However, the modulation method is not limited to the FM-CW method, and for example, the FCM (Fast-Chirp Modulation) method may also be used. When the FCM method is used as the modulation method, the high-frequency signal generating circuit 14 generates an FCM signal and outputs the FCM signal to the radio wave transmitting unit 15 and the radio wave receiving unit 16.

[0025] The radio wave transmitting unit 15 includes a transmitting circuit 15-1. The radio wave transmitting unit 15 radiates radio waves from a transmitting antenna element toward the interior of the vehicle cabin. If there are multiple transmitting antenna elements, the radio wave transmitting unit 15 radiates radio waves from, for example, any one of the multiple transmitting antenna elements toward the interior of the vehicle cabin. That is, the radio wave transmitting unit 15 sequentially switches between the multiple transmitting antenna elements to radiate radio waves. Note that this is merely an example, and the radio wave transmitting unit 15 may, for example, simultaneously radiate radio waves from multiple transmitting antenna elements toward the interior of the vehicle cabin. In this case, the radio wave transmitting unit 15 can distinguish which transmitting antenna element transmitted the signal using a known technique such as encoding. When radiating radio waves from the transmitting antenna element, the radio wave transmitting unit 15 outputs an FM signal from the transmitting circuit 15-1 to the transmitting antenna element.

[0026] The transmitting circuit 15-1 amplifies the FM signal output from the high frequency signal generating circuit 14 and outputs the amplified FM signal to the transmitting antenna element, thereby causing the transmitting antenna element to radiate an FM transmission wave, which is an electric wave, toward the interior area of ​​the vehicle cabin.

[0027] The radio wave receiving unit 16 has a receiving circuit 16-1. When an FM reception wave, which is a reflected wave, is received by the receiving antenna element, the receiving circuit 16-1 acquires a reception signal of the FM reception wave from the receiving antenna element. The receiving circuit 16-1 calculates a difference f between the frequency of the FM signal output from the high frequency signal generating circuit 14 and the frequency of the reception signal (hereinafter referred to as "frequency difference"). ｄ The receiving circuit 16-1 extracts the frequency difference f ｄ and outputs the intermediate frequency signal IF to the A / D conversion circuit 17.

[0028] Although FIG. 1 shows only one transmitting antenna Tx, one receiving antenna Rx, one transmitting circuit 15-1, and one receiving circuit 16-1, the system may be configured with multiple transmitting antennas Tx, multiple receiving antennas Rx, multiple transmitting circuits 15-1, or multiple receiving circuits 16-1.

[0029] The A / D conversion circuit 17 converts the intermediate frequency signal IF output from the receiving circuit 16-1 from an analog signal into a digital signal D. The A / D conversion circuit 17 outputs the digital signal D to the signal processing unit .

[0030] The signal processing unit 18 is realized by, for example, a digital signal processing circuit. The signal processing unit 18 acquires, from the A / D conversion circuit 17, a digital signal D related to the FM reception wave received by the reception circuit 16-1. The signal processing unit 18 detects an object present within the vehicle cabin based on the digital signal D. The signal processing unit 18 also determines the position of the detected object, in other words, the distance and angle to the object, based on the digital signal D. The signal processing unit 18 also determines the relative speed of the detected object based on the digital signal D. The signal processing unit 18 also determines the signal strength of a reflected wave, which is a radiated wave reflected by an object, based on the digital signal D. The signal processing unit 18 then generates sensor information. The sensor information includes reflected power information indicating the signal strength of the reflected wave, speed information indicating the speed of the detected object, or position information indicating the position (distance and angle) of the detected object. The signal processing unit 18 may apply an MTI (Moving Target Indicators) filter to suppress reflections from vehicle structures such as seats (front seats or rear seats), doors, or the ceiling based on the acquired digital signal D, and then perform frequency analysis on the suppressed digital signal D. After that, the signal processing unit 18 may identify the distance and angle to the object, the relative speed of the object, and the signal strength of the reflected wave to generate sensor information. The signal processing unit 18 outputs the generated sensor information to the living body detection device 1.

[0031] The digital signal processing circuit may be realized, for example, by a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. The digital signal processing circuit is not limited to being realized by dedicated hardware, but may also be realized by software, firmware, or a combination of software and firmware. The software or firmware is stored as a program in the memory of a computer. The computer refers to hardware that executes a program, and includes, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor).

[0032] A description will be given of a configuration example of the living body detection device 1 according to embodiment 1. As shown in the configuration example in Fig. 2 , the living body detection device 1 includes a sensor information acquisition unit 101, a region setting unit 102, a distance calculation unit 103, a detection unit 104, and an output unit 105.

[0033] The sensor information acquisition unit 101 acquires sensor information from the signal processing unit 18. The sensor information acquisition unit 101 outputs the acquired sensor information to the region setting unit 102.

[0034] The region setting unit 102 performs a "region setting process" to set a region of interest within the vehicle cabin and to set a first region of interest, a second region of interest, and a third region of interest. In the first embodiment, the region of interest refers to a columnar region within the vehicle cabin that has a height in the height direction of the seat (front seat or rear seat) and is the target region for the living body detection device 1 to detect the presence or absence of a living body based on sensor information. The region setting unit 102 sets a region of interest for each seat within the vehicle cabin. The first region of interest, the second region of interest, and the third region of interest will be described later. First, the setting of the region of interest by the region setting unit 102 will be described.

[0035] Here, FIG. 4 is a diagram showing an example of a target area set by the area setting unit 102 in the first embodiment. For convenience, FIG. 4 shows only the radio wave sensor 10 and one seat. In FIG. 4, "S" indicates a seat, and "C" indicates the position of the radio wave sensor 10. In the first embodiment, the position of the radio wave sensor 10 is represented, for example, by the installation position of the radio wave transmitter 15 of the radio wave sensor 10. In FIG. 4, the target area is indicated by "R1." The lines L1 to L3 and points P1 to P3 shown in FIG. 4 will be described later.

[0036] The region setting unit 102 sets, for example, a columnar region in the interior of the vehicle cabin, having a bottom surface that is a surface including the seat surface of a square or rectangular seat (hereinafter referred to as the "seat top surface") and an upper surface that is the seat top surface when moved to the top end of the seat backrest, as the target region. The seat top surface is, for example, a square or rectangular virtual surface with the four corners of the seat surface as its four corners. Note that in the first embodiment, the headrest is included in the backrest. Therefore, the region setting unit 102 sets, as the target region, a columnar region having a bottom surface that is the seat top surface and an upper surface that is the seat top surface when moved to the top end of the headrest, as the target region. For example, as shown in FIG. 4, the region setting unit 102 sets, as the target region, an area through which the seat top surface passes when the seat top surface is translated to the height of the top end of the headrest. The target area is an area having the shape of a rectangular prism, with the top surface of the seat (see "A" in Figure 4) as its bottom surface and the top surface of the seat (see "B" in Figure 4) when it is moved parallel to the height of the top end of the headrest.

[0037] Note that the target region shown in Figure 4 is merely an example, and the region setting unit 102 may set a region having a shape other than the shape of the target region shown in Figure 4 as the target region. The region setting unit 102 may set, in the vehicle interior region, a columnar region whose bottom surface is a surface in front of the seat back that includes at least the upper surface of the seat, and whose height reaches the top end of the seat back. For example, the target region may be a region having a cylindrical shape or a region having a pentagonal prism shape.

[0038] When the region setting unit 102 sets the target region, it sets the following first target point, second target point, and third target point.

[0039] The first target point is a point on the top surface of the target area and is located closest to the position of the radio wave sensor 10 (indicated by "P1" in FIG. 4). In the first embodiment, "closest to the position of the radio wave sensor 10" is not limited to being strictly closest, but also includes being close to the position of the radio wave sensor 10 within a margin of error. When there are multiple first target points, the distance calculation unit 103 may select any one point as the first target point.

[0040] The second target point is a point on the top surface of the target area and is located farthest from the position of the radio wave sensor 10 compared to the first target point (shown as "P2" in FIG. 4). In the first embodiment, the second target point is the point on the top surface of the target area that is located farthest from the position of the radio wave sensor 10. Note that in the first embodiment, "farthest from the position of the radio wave sensor 10" is not limited to being strictly the farthest, but also includes being farthest from the position of the radio wave sensor 10 within a margin of error. When there are multiple second target points, the distance calculation unit 103 may select any one point as the second target point.

[0041] The third target point is the point in the target region that is farthest from the second target point (shown as "P3" in FIG. 4). Note that in the first embodiment, "farthest from the second target point" does not necessarily mean being the farthest in the strict sense, but also means being farthest from the second target point within a margin of error.

[0042] The area setting unit 102 outputs information about the set target area, first target point, second target point, and third target point (hereinafter referred to as "target area information") to the distance calculation unit 103. At this time, the area setting unit 102 outputs the sensor information acquired from the sensor information acquisition unit 101 to the distance calculation unit 103 together with the target area information. The target area information is information that can identify the position and size of the target area in the real space inside the vehicle cabin, and information that includes the coordinates of the first target point, the second target point, and the third target point in the real space inside the vehicle cabin. For example, if the target area is a cylindrical area, the target area information includes the center and radius of the bottom surface of the target area and the center and radius of the top surface of the target area. For example, the target area information may include the coordinates of the edge of the bottom surface of the target area and the coordinates of the edge of the top surface of the target area.

[0043] The real space inside the vehicle cabin is represented by three-dimensional coordinate axes, for example, with the x-axis being an axis parallel to the vehicle width direction, the y-axis being an axis parallel to the vehicle height direction, and the z-axis being an axis parallel to the vehicle length direction. Because the position of the seat in the real space inside the vehicle cabin, the size of the seat, the height of the backrest including the headrest, etc. are known in advance, the area setting unit 102 can calculate each coordinate in the real space inside the vehicle cabin that can identify the target area.

[0044] The region setting unit 102 may, for example, acquire information about the current tilt of the seat back and the fore-and-aft position of the seat from a seat sensor (not shown) provided in the vehicle, and set the target region and calculate the coordinates of each of the first target point, the second target point, and the third target point in the real space in the vehicle interior where the target region can be identified. This allows the region setting unit 102 to set the target region that more closely reflects the current state of the seat and to calculate the coordinates of the first target point, the second target point, and the third target point.

[0045] Here, as an example, the region setting unit 102 sets the target region as a region in the shape of a rectangular prism, as shown in FIG. 4 . Furthermore, the region setting unit 102 generates information including the coordinates of the ends of the bottom surface of the target region, i.e., the coordinates of the four corners of the bottom surface of the target region, and the coordinates of the ends of the top surface of the target region, i.e., the coordinates of the four corners of the top surface of the target region, as target region information, and outputs this information to the distance calculation unit 103. The region setting unit 102 assigns information that enables identification of the coordinates of the first target point or the second target point among the coordinates of the four corners of the top surface of the target region. Furthermore, the region setting unit 102 assigns information that enables identification of the coordinates of the third target point among the coordinates of the four corners of the bottom surface of the target region. The region setting unit 102 may, for example, include information indicating the height of the target region in the target region information.

[0046] The distance calculation unit 103 calculates the following first distance, second distance, and third distance from the position of the radio wave sensor 10 and the target area set by the area setting unit 102. The first distance is the distance from the position of the radio wave sensor 10 to the first target point. The first distance is indicated by "L1" in FIG. 4. The second distance is the distance from the position of the radio wave sensor 10 to the second target point. The second distance is indicated by "L2" in FIG. 4. The third distance is the distance from the second target point to the third target point. The third distance is indicated by "L3" in FIG. 4.

[0047] In this example, the first target point is point P1 shown in Fig. 4, the second target point is point P2 shown in Fig. 4, and the third target point is point P3 shown in Fig. 4. The distance calculation unit 103 calculates the distance from the position of the radio wave sensor 10 (position "C" in Fig. 4) to point P1 as the first distance, calculates the distance from the position of the radio wave sensor 10 to point P2 as the second distance, and calculates the distance from point P2 to point P3 as the third distance. Note that the position of the radio wave sensor 10 is known in advance, and the positions of points P1 to P3 can be determined from the target area information.

[0048] Distance calculation unit 103 outputs information on the calculated first distance, second distance, and third distance (hereinafter referred to as "target distance information") to detection unit 104. At this time, distance calculation unit 103 outputs the sensor information output from area setting unit 102 to detection unit 104 together with the target distance information.

[0049] The detection unit 104 detects whether or not an occupant is present in the vehicle cabin based on the sensor information acquired by the sensor information acquisition unit 101 and the first distance, the second distance, and the third distance calculated by the distance calculation unit 103. The distance calculation unit 103 can determine the first distance, the second distance, and the third distance from the target distance information output from the distance calculation unit 103.

[0050] Here, a description will be given of an example of a method for detecting whether or not an occupant is present in the vehicle cabin based on the sensor information and the target distance information by the detection unit 104. Note that the detection unit 104 detects whether or not an occupant is present for each seat.

[0051] For example, the ranges of spaces within the vehicle cabin corresponding to each seat (driver's seat, passenger seat, left rear seat, middle rear seat, right rear seat, etc.) are determined in advance. The detection unit 104 can, for example, determine from the position information included in the sensor information, the space corresponding to which seat the distance to the detected object was detected. Also, for example, in the radio wave sensor 10, the signal processing unit 18 can identify the seat from which the distance to the object was detected based on the received wave obtained in response to which transmitted wave the distance to the object is based, and associate information indicating the identified seat with the position information. The detection unit 104 can, from the information indicating the seat associated with the position information, identify the space corresponding to which seat the distance indicated by the position information included in the sensor information was detected from.

[0052] For example, the detection unit 104 detects that an occupant is present in the vehicle cabin when the distance to the object detected by the radio wave sensor 10 satisfies the following first detection condition: Note that the detection unit 104 can determine the distance to the object detected by the radio wave sensor 10 from the position information included in the sensor information.

[0053] <First detection condition> "The distance to the object detected by the radio wave sensor 10 is equal to or greater than the first distance and equal to or less than the sum of the second distance and the third distance (hereinafter referred to as the "fourth distance")."

[0054] The detection unit 104 detects that an occupant is present in the vehicle cabin if the distance to the object detected by the radio wave sensor 10 satisfies the first detection condition, in other words, if the distance to the object detected by the radio wave sensor 10 is equal to or greater than the first distance and equal to or less than the fourth distance. On the other hand, the detection unit 104 detects that an occupant is not present in the vehicle cabin if the distance to the object detected by the radio wave sensor 10 does not satisfy the first detection condition, in other words, if the distance to the object detected by the radio wave sensor 10 is not equal to or greater than the first distance and equal to or less than the fourth distance, that is, if the distance to the object detected by the radio wave sensor 10 is shorter than the first distance or longer than the fourth distance.

[0055] 5A, 5B, and 5C are diagrams illustrating an example in which the detection unit 104 detects whether a living body is present in the vehicle cabin based on whether the distance to an object detected by the radio wave sensor 10 satisfies a first detection condition in the first embodiment. FIGS. 5A, 5B, and 5C are side views of the vehicle, and for convenience, only the front or rear seats and the occupants seated in the front or rear seats are illustrated. In FIGS. 5A, 5B, and 5C, the front seats are indicated by "S1," and in FIG. 5C, the rear seats are indicated by "S2." In FIGS. 5A, 5B, and 5C, arrows indicate images of radio waves emitted from the radio wave sensor 10. In FIGS. 5A, 5B, and 5C, dotted lines indicate target areas.

[0056] Fig. 5A shows an example of the interior of a vehicle with an adult (indicated by "H1" in Fig. 5A) sitting upright in the front seat. Fig. 5B shows an example of the interior of a vehicle with an infant (indicated by "H2" in Fig. 5B) sitting in a rearward-facing child car seat in the front seat. Note that in the first embodiment, "occupant seated" includes an infant in a child car seat. Fig. 5C shows an example of the interior of a vehicle with a child (indicated by "H3" in Fig. 5C) lying down in the rear seat.

[0057] In the example shown in FIG. 5A , an occupant is seated in a front seat with the radio wave sensor 10 irradiating radio waves to an area in the vehicle interior in front of the seat back. There are no interior structures or the like between the occupant and the radio wave sensor 10 that would block the radio waves irradiated from the radio wave sensor 10. Therefore, the radio waves irradiated from the radio wave sensor 10 reach the occupant directly. In other words, the radio wave sensor 10 can directly see the occupant. In this case, the distance to the object (i.e., the occupant) detected by the radio wave sensor 10 is assumed to be equal to or greater than a first distance and equal to or less than a fourth distance in the target area set for the front seat. The detection unit 104 determines whether the distance to the object detected by the radio wave sensor 10 satisfies a first detection condition. If the distance to the object satisfies the first detection condition, the detection unit 104 detects the presence of an occupant in the vehicle interior.

[0058] In the example shown in FIG. 5B , an occupant is seated in the front seat, similar to the example shown in FIG. 5A . However, while the adult in the example shown in FIG. 5A is seated upright, the infant in the example shown in FIG. 5B is seated in a rearward-facing child car seat. In this case, the child car seat acts as a shield, preventing radio waves from the radio wave sensor 10 from reaching the occupant directly. In other words, the radio wave sensor 10 cannot directly see the occupant. However, the radio waves from the radio wave sensor 10 are reflected by, for example, the backrest of the front seat and radiated toward the occupant. In this case, the distance from the radio wave sensor 10 to the occupant via the backrest of the front seat is assumed to be equal to or greater than the first distance and equal to or less than the fourth distance within the target area set for the front seat. Because the radio waves from the radio wave sensor 10 do not reach the occupant directly but are reflected by the backrest of the front seat and reach the occupant, the detected distance to the occupant is longer than when the radio waves are radiated directly toward the occupant. However, the distance to the occupant sitting in the seat is a distance detected based on the received waves from the reflected waves that are reflected by the backrest of the front seat and reach the occupant on the seat surface (more specifically, on a child seat installed on the seat surface), and is assumed to be no longer than the fourth distance. The detection unit 104 determines whether the distance to the object (i.e., the occupant) detected by the radio wave sensor 10 satisfies the first detection condition, and detects the presence of an occupant in the vehicle compartment if the distance to the object satisfies the first detection condition, thereby making it possible to detect the presence of an occupant in the vehicle compartment who is not directly irradiated with radio waves from the radio wave sensor 10 due to an obstruction.

[0059] In the example shown in FIG. 5C , the front seats act as a shield, preventing radio waves from the radio wave sensor 10 from reaching the occupant directly. In other words, the radio wave sensor 10 cannot directly see the occupant. However, the radio waves from the radio wave sensor 10 are reflected by, for example, the backrest of the rear seat and irradiated toward the occupant. In this case, the distance from the radio wave sensor 10 to the occupant via the backrest of the rear seat is assumed to be equal to or greater than the first distance and equal to or less than the fourth distance within the target area set for the rear seat. Because the radio waves from the radio wave sensor 10 do not reach the occupant directly but instead reflect off the backrest of the rear seat and reach the occupant, the detected distance to the occupant is longer than when the radio waves are directly irradiated toward the occupant. However, the distance to the seated occupant is detected based on the received waves from the reflected waves that are reflected off the backrest of the rear seat and reach the occupant sitting on the seat, and is assumed to be no longer than the fourth distance. The detection unit 104 determines whether the distance to the object (i.e., the occupant) detected by the radio wave sensor 10 satisfies the first detection condition, and detects that an occupant is present in the vehicle cabin if the distance to the object satisfies the first detection condition, thereby being able to detect the presence of an occupant even if the radio waves are not directly irradiated from the radio wave sensor 10.

[0060] In embodiment 1, if the distance to the object detected by the radio wave sensor 10 satisfies the first detection condition described above, the detection unit 104 may further determine whether the detected object is a living organism based on the sensor information, and if it determines that the detected object is a living organism, may detect that an occupant is present in the vehicle cabin.

[0061] Specifically, the detection unit 104 may detect that an occupant is present in the vehicle cabin when the distance to an object detected by the radio wave sensor 10 satisfies the first detection condition described above, and when the reflected power information, speed information, or position information included in the sensor information satisfies a preset condition (hereinafter referred to as the "living body detection condition"). In the first embodiment, the living body detection condition is a condition for detecting whether or not an object is a living body. The living body detection condition is set by an administrator or the like, for example, as the following (Condition 1-1) to (Condition 1-3). (Condition 1-1) The signal strength is equal to or greater than a predetermined threshold (hereinafter referred to as the "first strength determination threshold"). (Condition 1-2) The speed of the object is equal to or greater than a predetermined threshold (hereinafter referred to as the "first speed determination threshold"). (Condition 1-3) The size or shape of the detected object is equal to or greater than a preset size or shape.

[0062] In (Condition 1-1), the first strength determination threshold is set in advance to a signal strength that is assumed to be the signal strength of a living body. In (Condition 1-2), the first speed determination threshold is set in advance to an appropriate speed. The living body is expected to be moving to some extent. In (Condition 1-3), the predetermined size or shape is set to an appropriate size or shape that can be considered to be the size or shape of a living body.

[0063] If the distance to the object detected by the radio wave sensor 10 satisfies the first detection condition described above, and the reflected power information, speed information, or position information contained in the sensor information satisfies, for example, any of (condition 1-1) to (condition 1-3), the detection unit 104 determines that the living body detection condition is met and detects that an occupant is present in the vehicle cabin.

[0064] For example, the detection unit 104 can detect whether a detected object is a living organism based on reflected power information included in the sensor information. For example, if the distance to an object detected by the radio wave sensor 10 satisfies the first detection condition described above and the signal strength is equal to or greater than the first intensity determination threshold, the detection unit 104 detects that the detected object is a living organism, in other words, that an occupant is present in the vehicle cabin. Furthermore, for example, the detection unit 104 can detect whether a detected object is a living organism based on speed information included in the sensor information. If the distance to an object detected by the radio wave sensor 10 satisfies the first detection condition described above and the object's speed is equal to or greater than a predetermined first speed determination threshold, the detection unit 104 detects that the detected object is a living organism, in other words, that an occupant is present in the vehicle cabin. Furthermore, for example, the detection unit 104 can detect whether a detected object is a living organism based on location information included in the sensor information. When the distance to the object detected by the radio wave sensor 10 satisfies the first detection condition described above, the detection unit 104 estimates the size or shape of the detected object, and if the size or shape of the object is a predetermined size or shape, it detects that the detected object is a living organism, in other words, that there is an occupant in the vehicle cabin.

[0065] The detection unit 104 may, for example, combine the above-mentioned (Condition 1-1) to (Condition 1-3) to determine whether the reflected power information, speed information, or position information contained in the sensor information satisfies the conditions for biological detection.

[0066] Furthermore, the detection unit 104 may determine whether or not the detected object is a living organism using, for example, a trained model (hereinafter referred to as a "first machine learning model") that receives sensor information as input and outputs information indicating whether or not the detected object is a living organism. When the distance to the object detected by the radio wave sensor 10 satisfies the above-described first detection condition and the detection unit 104 inputs sensor information to the first machine learning model and obtains information indicating that the object is a living organism, the detection unit 104 detects that the detected object is a living organism, in other words, that an occupant is present in the vehicle cabin.

[0067] There is a possibility that a non-living object may be present on the seat, such as a plastic container filled with water, a golf bag, a bag filled with rice, etc. As described above, the detection unit 104 determines whether the detected object is a living object by using the living object detection conditions or the first machine learning model, thereby preventing the non-living object from being mistakenly detected as an occupant.

[0068] Note that, although the detection unit 104 is assumed to determine whether the detected object is a living organism here, this is merely an example. For example, the signal processing unit 18 may determine whether the detected object is a living organism using the method described above, and if it determines that the detected object is a living organism, generate sensor information and output it to the living organism detection device 1. In this case, the detection unit 104 does not need to consider whether the object based on the sensor information is a non-living object. In other words, the detection unit 104 can detect whether an occupant is present in the vehicle cabin based on the sensor information, for example, by determining whether the first detection condition described above is satisfied, while preventing erroneous detection of a non-living object as an occupant.

[0069] The detection unit 104 outputs the detection result of whether or not an occupant is present in the vehicle compartment (hereinafter referred to as the “occupant detection result”) to the output unit 105 .

[0070] The output unit 105 outputs the occupant detection result output from the detection unit 104 to the abandoned vehicle detection device 200. The detection unit 104 may have the function of the output unit 105.

[0071] The abandonment detection device 200 outputs an alarm based on the occupant detection result output from the output unit 105. For example, the abandonment detection device 200 is connected to a speaker (not shown) mounted on the vehicle, and when the output unit 105 outputs an occupant detection result indicating the presence of an occupant in the vehicle cabin, the abandonment detection device 200 causes the speaker to output an alarm sound. In this way, the abandonment detection device 200 notifies people around the vehicle that an abandonment has occurred in the vehicle cabin. Also, for example, the abandonment detection device 200 is connected to a mobile terminal (not shown) carried by the vehicle owner, and when the output unit 105 outputs an occupant detection result indicating the presence of an occupant in the vehicle cabin, the abandonment detection device 200 causes an alarm message or alarm sound to be output from an output device provided on the mobile terminal. In this way, the abandonment detection device 200 notifies the vehicle owner that an abandonment has occurred in the vehicle cabin.

[0072] The operation of the living body detection device 1 according to the first embodiment will be described. Fig. 6 is a flowchart for describing the operation of the living body detection device 1 according to the first embodiment. For example, when the vehicle stops, the living body detection device 1 performs the operation shown in the flowchart of Fig. 6. The living body detection device 1 performs the operation shown in the flowchart of Fig. 6 for each seat in the vehicle cabin, and repeats the operation shown in the flowchart of Fig. 6 until the detection process for determining whether or not an occupant is present in all seats is completed, or until the presence of an occupant is detected in any seat.

[0073] The sensor information acquisition unit 101 acquires sensor information from the signal processing unit 18 (step ST1). The sensor information acquisition unit 101 outputs the acquired sensor information to the region setting unit 102.

[0074] The region setting unit 102 performs a target region setting process (step ST2). Specifically, the region setting unit 102 sets a target region within the vehicle cabin, and also sets a first target point, a second target point, and a third target point. The region setting unit 102 outputs the target region information to the distance calculation unit 103. At this time, the region setting unit 102 outputs the sensor information acquired from the sensor information acquisition unit 101 to the distance calculation unit 103 together with the target region information.

[0075] The distance calculation unit 103 calculates the first distance, the second distance, and the third distance from the position of the radio wave sensor 10 and the target area set by the area setting unit 102 in step ST2 (step ST3). The distance calculation unit 103 outputs the target distance information to the detection unit 104. At this time, the distance calculation unit 103 outputs the sensor information output from the area setting unit 102 to the detection unit 104 together with the target distance information.

[0076] The detection unit 104 detects whether or not an occupant is present in the vehicle cabin based on the sensor information acquired by the sensor information acquisition unit 101 in step ST1 and the first distance, the second distance, and the third distance calculated by the distance calculation unit 103 in step ST3 (step ST4). For example, the detection unit 104 detects the presence of an occupant in the vehicle cabin when the distance to the object detected by the radio wave sensor 10 satisfies the first detection condition described above. For example, when the distance to the object detected by the radio wave sensor 10 satisfies the first detection condition described above, the detection unit 104 may further determine whether the detected object is a living body based on the sensor information, and detect the presence of an occupant in the vehicle cabin when it determines that the detected object is a living body. The detection unit 104 outputs the occupant detection result to the output unit 105.

[0077] The output unit 105 outputs the occupant detection result output from the detection unit 104 to the abandoned vehicle detection device 200 (step ST5).

[0078] 6, the processing is performed in the order of step ST1 and step ST2, but the order of the processing of step ST1 and step ST2 is not limited to this. The processing of step ST1 and the processing of step ST2 may be performed in parallel, or the processing of step ST1 may be performed after the processing of step ST2.

[0079] As described above, the living body detection device 1 according to the first embodiment sets a columnar target area having a height in the direction of the height of the seats as a target for detecting the presence or absence of a living body based on sensor information generated based on reflected waves of radio waves emitted by the radio wave sensor 10 toward an area of ​​the vehicle interior including at least the seats present in the vehicle interior. The living body detection device 1 also sets a first target point, which is a point on the top surface of the target area and closest to the position of the radio wave sensor 10, a second target point, which is a point on the top surface of the target area and farthest from the position of the radio wave sensor 10 relative to the first target point, and a third target point, which is a point in the target area farthest from the second target point. The living body detection device 1 calculates a first distance from the position of the radio wave sensor 10 to the first target point, a second distance from the position of the radio wave sensor 10 to the second target point, and a third distance from the second target point to the third target point. The living body detection device 1 then detects whether or not an occupant is present in the vehicle cabin based on the sensor information and the first distance, the second distance, and the third distance. This allows the living body detection device 1 to detect an occupant present in the vehicle cabin. More specifically, the living body detection device 1 can detect an occupant present in the vehicle cabin even if the occupant is present in a blind spot from the radio wave sensor 10, such as a location blocked by an interior vehicle structure that reflects the radiated radio waves.

[0080] If the radio wave sensor 10 were installed on the ceiling above each seat, the possibility of the radio waves emitted from the radio wave sensor 10 being directly irradiated to the occupant sitting in the seat would increase, even if the occupant were in a location blocked by another seat located in front of the seat (see, for example, FIG. 5C ). However, some vehicle models may be equipped with a skylight on the ceiling above the seat. This may limit the number of vehicle models that can detect the presence or absence of an occupant in the vehicle cabin based on sensor information generated by the radio wave sensor 10 installed on the ceiling. Furthermore, from the perspective of wiring routing, it is not desirable to install the radio wave sensor 10 on the ceiling. Even if the radio wave sensor 10 were installed on the ceiling above the seat, for example, if an object that blocks radio waves were covering the occupant sitting on the seat, the occupant would not be directly irradiated with radio waves. As described above, the living body detection device 1 according to the first embodiment is capable of detecting an occupant in the vehicle cabin by utilizing the phenomenon in which radio waves from the radio wave sensor 10 are reflected by structures in the vehicle cabin and irradiated onto the occupant. As a result, there is increased flexibility in the installation location of the radio wave sensor 10, which generates sensor information used by the living body detection device 1 to detect an occupant. Because there is increased flexibility in the installation location of the radio wave sensor 10, the living body detection device 1 is not limited to certain vehicle models that can detect whether an occupant is present in the vehicle cabin.

[0081] In the first embodiment described above, when the living body detection device 1 detects the presence of an occupant in the vehicle cabin, it outputs occupant detection information indicating the presence of an occupant in the vehicle cabin to the abandoned vehicle detection device 200. The abandoned vehicle detection device 200 then outputs an alarm when the living body detection device 1 detects the presence of an occupant in the vehicle cabin. However, if the occupant in the vehicle cabin is, for example, an adult who is capable of leaving the vehicle cabin on his or her own, the occupant cannot be considered abandoned. The abandoned vehicle detection device 200 does not need to output an alarm when an occupant who is capable of leaving the vehicle cabin on his or her own is present in the vehicle cabin. Therefore, for example, the living body detection device 1 may determine whether the occupant detected in the vehicle cabin requires assistance and output the determination result to the abandoned vehicle detection device 200. This allows the abandoned vehicle detection device 200 to output an alarm according to the situation in the vehicle cabin that is truly deemed necessary. More specifically, the abandoned vehicle detection device 200 may output an alarm when an occupant in the vehicle cabin requires assistance. In the first embodiment, the person requiring assistance is assumed to be a living being that is unable to get out of the vehicle compartment by itself, such as an infant or a pet.

[0082] Specifically, in the living body detection device 1, the detection unit 104 detects whether or not there is an occupant in the vehicle cabin, and if it detects that there is an occupant in the vehicle cabin, it can determine whether or not the occupant is a person requiring assistance.

[0083] The detection unit 104 can determine whether or not a living organism requires assistance based on the sensor information. For example, the detection unit 104 determines that the living organism requires assistance when reflected power information, speed information, or position information included in the biological information satisfies a predetermined condition (hereinafter referred to as "condition for determining an individual requiring assistance"). In the first embodiment, the condition for determining an individual requiring assistance is a condition for determining whether or not an object requires assistance. The condition for determining an individual requiring assistance is set by an administrator or the like, for example, as the following (Condition 2-1) to (Condition 2-3). (Condition 2-1) The signal strength is equal to or greater than a first strength determination threshold and is equal to or less than a predetermined threshold (hereinafter referred to as a "second strength determination threshold"). (Condition 2-2) The speed of the object is equal to or greater than the first strength determination threshold and is equal to or less than a predetermined threshold (hereinafter referred to as a "second speed determination threshold"). (Condition 2-3) The size or shape of the detected object is a predetermined size or shape.

[0084] In (Condition 2-1), the second intensity determination threshold is set in advance to a signal strength that is assumed to be the signal strength of the reflected wave that strikes, for example, an infant. For example, between an adult and a child, an adult is larger in body size, and the area struck by the radio waves emitted from the radio wave sensor 10 is larger. The larger the area struck by the radiated radio waves, the greater the signal strength of the reflected wave. In (Condition 2-2), an appropriate speed is set in advance to the second speed determination threshold. Living organisms are expected to move to a certain extent. For example, an example of a person requiring assistance is an infant in a child seat, and it is assumed that the movement of such an infant in a child seat is more restricted than that of an adult. In (Condition 2-3), the predetermined size or shape is set to an appropriate size or shape that can be considered to be the size or shape of an infant, for example.

[0085] If the reflected power information, speed information, or position information contained in the sensor information satisfies, for example, any of (Condition 2-1) to (Condition 2-3), the detection unit 104 determines that the conditions for determining whether an occupant requires assistance are met, and determines that the occupant present in the vehicle cabin is a person requiring assistance.

[0086] The detection unit 104 determines that the detected occupant requires assistance, for example, if the signal strength based on the reflected power information included in the biometric information is equal to or greater than a first strength determination threshold and equal to or less than a second strength determination threshold. The detection unit 104 also determines that the detected occupant requires assistance, for example, if the speed of the object based on the speed information included in the sensor information is equal to or greater than a first speed determination threshold and equal to or less than a second speed determination threshold. The detection unit 104 also determines that the detected occupant requires assistance, for example, if the size or shape of the occupant based on the position information included in the sensor information is a predetermined size or shape.

[0087] The detection unit 104 may, for example, combine the above-mentioned (Condition 2-1) to (Condition 2-3) to determine whether the reflected power information, speed information, or position information contained in the sensor information satisfies the conditions for determining whether the person requires assistance.

[0088] Furthermore, the detection unit 104 may determine whether or not the detected occupant requires assistance by using, for example, a trained model (hereinafter referred to as a "second machine learning model") that receives sensor information as input and outputs information indicating whether or not the detected object requires assistance. When the detection unit 104 inputs sensor information into the second machine learning model and obtains information indicating that the object requires assistance, the detection unit 104 determines that the detected occupant requires assistance.

[0089] When the detection unit 104 determines whether an occupant requires assistance, it outputs to the output unit 105, as an occupant detection result, information indicating whether it has detected that an occupant is present in the vehicle cabin and, if it has detected that an occupant is present, information indicating whether the occupant requires assistance.

[0090] The output unit 105 outputs the occupant detection result output from the detection unit 104 to the abandonment detection device 200. The abandonment detection device 200 outputs an alarm when a person requiring assistance is detected in the vehicle cabin based on the occupant detection result output from the output unit 105. This allows the abandonment detection device 200 to prevent unnecessary alarms from being output. The living body detection device 1 can provide the occupant detection result to the abandonment detection device 200 in a form that prevents unnecessary alarms from being output. Note that, for example, in the living body detection device 1, the output unit 105 may be configured to output the occupant detection result to the abandonment detection device 200 when the only occupant in the vehicle cabin detected by the detection unit 104 is a person requiring assistance.

[0091] In the first embodiment, the target area is an area above the seat surface, but this is merely an example. The target area may also include an area below the seat surface. In this case, in addition to the area above the seat surface of the front seat or the rear seat, the area on the floor below the seat surface of the front seat or the rear seat is also included in the vehicle interior area.

[0092] Here, Fig. 7 is a diagram showing an example of a target area set by the area setting unit 102 in the target area setting process when the area setting unit 102 includes an area below the seat surface in the target area in embodiment 1. For convenience, Fig. 7 shows only the radio wave sensor 10 and one seat. In Fig. 7, "S" indicates the seat, and "C" indicates the position of the radio wave sensor 10. Also, in Fig. 7, the target area is indicated by "R2." The lines L1-L2 and L5 and points P1-P2 and P4 shown in Fig. 7 will be described later.

[0093] For example, the region setting unit 102 may include, in the vehicle interior region, a region below the surface including the seat surface, specifically, the region around the feet of the seat (hereinafter referred to as the "foot region"), as the target region. For example, the region setting unit 102 may define, as the target region, a columnar region having a height from the floor to the top of the seat back, with the floor surface around the feet of the seat (hereinafter referred to as the "foot upper surface") corresponding to the seat as the bottom surface and the seat upper surface moved to the top of the seat back as the top surface. Note that the size of the foot upper surface corresponding to each seat in the vehicle interior is predetermined. In FIG. 7, as an example, the foot upper surface corresponding to the seat is the floor surface including the area under and in front of the seat and having the same width as the seat. Note that "the same width as the seat" is not limited to being exactly the same width, but may also include being approximately the same width. For example, as shown in Figure 7, the area setting unit 102 sets the target area to a columnar area whose bottom surface is the upper surface of the foot area corresponding to the seat (see "D" in Figure 7) and whose top surface is the upper surface of the seat when the upper surface of the seat is in a position translated to the height of the upper end of the headrest (see "B" in Figure 7).

[0094] The target region shown in FIG. 7 is merely an example, and the region setting unit 102 may set a region having a shape other than the shape of the target region shown in FIG. 7 as the target region.

[0095] After setting the target region, the region setting unit 102 sets a first target point, a second target point, and a third target point. Here, the third target point, i.e., the point in the target region that is farthest from the second target point, is the point indicated by "P4" in FIG. 7.

[0096] In this case, the area setting unit 102 may also obtain information regarding the current tilt of the seat back and the front and rear positions of the seat from a seat sensor installed in the vehicle, and set the target area and calculate the coordinates of each of the first target point, second target point, and third target point in the real space within the vehicle cabin where the target area can be identified.

[0097] The region setting unit 102 outputs the target region information together with the sensor information to the distance calculation unit 103. Note that the height, width, depth, and size of the upper surface of the foot area are known in advance, so the region setting unit 102 can identify the coordinates of the four corners of the upper surface of the foot area that correspond to the seat.

[0098] In this case, the distance calculation unit 103 calculates the distance from the position of the radio wave sensor 10 to the third target point indicated by "P4" in Fig. 7 as the third distance. In Fig. 7, the third distance is indicated by "L5." Note that in Fig. 7, the first distance is indicated by "L1" and the second distance is indicated by "L2."

[0099] In the living body detection device 1, the area setting unit 102 includes the area below the surface including the seat surface, specifically the foot area, in the target area, so that the living body detection device 1 can detect occupants who are present below the seat surface, such as a child who has crawled under the seat surface.

[0100] Furthermore, in the first embodiment, the radio wave transmitter / receiver 19 of the radio wave sensor 10 may control the radiation range of the radio waves. Specifically, the radio wave transmitter / receiver 19 controls the radio wave sensor 10, more specifically, the transmitting antenna Tx, to direct the radio waves toward the center of the seat back to minimize the possibility of the radio waves being reflected by interior structures or by other occupants sitting on the seat back of the seat. The radio wave transmitter / receiver 19 may control the radio waves radiated from the transmitting antenna Tx using a known method. Known methods for controlling the radio waves radiated from the transmitting antenna Tx include digital beam forming (DBF) and capon (Capon). The radio wave transmitter / receiver 19 can also control the receiving direction of the reflected waves received by the receiving antenna Rx in addition to the transmitting side using DBF or capon. Note that control of radio waves using methods such as DBF or Capon is applicable when at least one of the transmitting antenna Tx and the receiving antenna Rx has multiple antenna elements (transmitting antenna elements or receiving antenna elements). For example, when the transmitting antenna Tx and the receiving antenna Rx each have one antenna element (transmitting antenna element or receiving antenna element), the radio wave transmitting / receiving unit 19 can control the radio waves to be directed toward the center of the seat back by, for example, using a lens to change the direction of the radiated radio waves or by mechanically moving the radio wave sensor 10 itself. Figure 8 is a diagram illustrating an example of how the radiation range of the radio waves radiated from the transmitting antenna Tx is controlled by the radio wave sensor 10 in the first embodiment. For convenience, Figure 8 illustrates only the radio wave sensor 10 and one seat. In Figure 8, "S" indicates the seat. Also, in Figure 8, the controlled radiation range of the radio waves is indicated by "E." The radio waves emitted from the transmitting antenna Tx are widely emitted toward the center of the seat back, and radiation of the radio waves to areas other than the center of the seat back is suppressed.

[0101] Furthermore, in the first embodiment described above, the living body detection device 1 is mounted on the radio wave sensor 10, but this is merely an example. The living body detection device 1 may be provided outside the radio wave sensor 10, and the radio wave sensor 10 and the living body detection device 1 may form a living body detection system. FIG. 9 is a diagram showing an example configuration of a living body detection system 1000 including the radio wave sensor 10 and the living body detection device 1 in the first embodiment. Note that FIG. 9 does not show specific configuration examples of the radio wave sensor 10 and the living body detection device 1. For example, the living body detection device 1 may be provided in the abandonment detection device 200, or may be provided in a server connected to the radio wave sensor 10 via a network.

[0102] In the first embodiment described above, the living body detection device 1 sets the target area, the first target point, the second target point, and the third target point and calculates the first distance, the second distance, and the third distance each time. However, this is merely an example. For example, the target area may be fixedly determined in advance within the vehicle interior. Since the installation position of the radio wave sensor 10 is known, if the target area is fixedly determined, the first target point, the second target point, the third target point, the first distance, the second distance, and the third distance may also be fixedly determined in advance. In the living body detection device 1, the detection unit 104 may store information on the predetermined target area, the first target point, the second target point, the third target point, the first distance, the second distance, and the third distance, and detect whether or not an occupant is present in the vehicle interior based on the stored information on the target area, the first target point, the second target point, the third target point, the first distance, the second distance, and the third distance. In this case, the living body detection device 1 does not necessarily have to include the region setting unit 102 and the distance calculation unit 103. Furthermore, with regard to the operation of the living body detection device 1 described using the flowchart of Fig. 6, the living body detection device 1 can omit the processes of steps ST2 to ST3.

[0103] In the first embodiment, the indoor space is assumed to be the interior of a vehicle, and the living body detection device 1 detects whether an occupant is present in the vehicle interior based on the sensor information generated by the radio wave sensor 10. However, this is merely an example. For example, the indoor space may be a moving object other than a vehicle, such as a ship or a train. For example, the occupant may be a passenger on a ship or a train. The living body detection device 1 can detect whether an occupant is present in the interior of various moving objects. Furthermore, the living body detection device 1 can detect whether a living body is present not only in the interior of a moving object but also in a room within a building. For example, the living body detection device 1 can detect whether a person is present in a room in a nursing home. The living body detection device 1 detects whether a person is present in a room and outputs the detection result to, for example, a monitoring device (not shown). The monitoring device can output an alarm indicating that a person has been left behind in the room. In this case, the living body detection device 1 may operate at a timing instructed by, for example, a manager. The living body detection device 1 can detect living bodies in various rooms, even if the living body is present in a location that is a blind spot for the radio wave sensor 10 due to structures or the like in the room, by taking advantage of the phenomenon in which radio waves from the radio wave sensor 10 are reflected by structures or the like in the room and irradiated onto the living body.

[0104] 10A and 10B are diagrams illustrating an example of the hardware configuration of the living body detection device 1 according to the first embodiment. In the first embodiment, the functions of the sensor information acquisition unit 101, the region setting unit 102, the distance calculation unit 103, the detection unit 104, and the output unit 105 are realized by a processing circuit 1001. That is, the living body detection device 1 includes the processing circuit 1001 for controlling the detection of whether or not a living body is present in a room. The processing circuit 1001 may be dedicated hardware as shown in FIG. 10A, or may be a processor 1004 that executes a program stored in a memory as shown in FIG. 10B.

[0105] If the processing circuit 1001 is dedicated hardware, the processing circuit 1001 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0106] When the processing circuit is the processor 1004, the functions of the sensor information acquisition unit 101, the region setting unit 102, the distance calculation unit 103, the detection unit 104, and the output unit 105 are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 1005. The processor 1004 reads and executes the program stored in the memory 1005 to execute the functions of the sensor information acquisition unit 101, the region setting unit 102, the distance calculation unit 103, the detection unit 104, and the output unit 105. In other words, the living body detection device 1 includes the memory 1005 for storing a program that, when executed by the processor 1004, results in the execution of steps ST1 to ST5 of FIG. 6 described above. In addition, the program stored in memory 1005 can also be said to cause the computer to execute the processing procedures or methods of the sensor information acquisition unit 101, the area setting unit 102, the distance calculation unit 103, the detection unit 104, and the output unit 105. Here, the memory 1005 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM, a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read-Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc).

[0107] Note that the functions of the sensor information acquisition unit 101, the region setting unit 102, the distance calculation unit 103, the detection unit 104, and the output unit 105 may be partially implemented by dedicated hardware and partially implemented by software or firmware. For example, the functions of the sensor information acquisition unit 101 may be implemented by a processing circuit 1001 as dedicated hardware, and the functions of the region setting unit 102, the distance calculation unit 103, the detection unit 104, and the output unit 105 may be implemented by the processor 1004 reading and executing a program stored in the memory 1005. The living body detection device 1 also includes an input interface device 1002 and an output interface device 1003 that communicate with devices such as the abandonment detection device 200 via wired or wireless communication.

[0108] As described above, according to the first embodiment, the living body detection device 1 is configured to include a sensor information acquisition unit 101 that acquires sensor information generated based on waves reflected by objects in the room when radio waves emitted by the radio wave sensor 10 toward an indoor area including at least the seats present in the room are reflected by the objects in the room, and a detection unit 104 that detects whether a living body is present in the room based on the sensor information acquired by the sensor information acquisition unit 101, a first distance from the position of the radio wave sensor 10 to a first target point, which is a point on the top surface of a columnar target area having a height in the height direction of the seats that is the target area for detecting the presence or absence of a living body based on the sensor information, a second distance from the position of the radio wave sensor 10 to a second target point, which is a point on the top surface of the target area that is the farthest from the position of the radio wave sensor 10, and a third distance from the second target point to a third target point, which is the farthest point in the target area from the second target point. Therefore, the living body detection device 1 can detect a living body present in the room. The living body detection device 1 can detect a living body in a room by taking advantage of the phenomenon in which radio waves from the radio wave sensor 10 are reflected by structures in the room and irradiated onto the living body, even if the living body is present in a location that is a blind spot for the radio wave sensor 10 due to structures in the room, etc.

[0109] Furthermore, according to the first embodiment, the target area of ​​the living body detection device 1 is a columnar area having the height of the seat back, with the seat top surface, which is the surface including the seat surface, as its bottom surface, and the seat top surface when moved to the top end of the seat back, as its top surface. Therefore, even if a living body is present in a location in a room that is in a blind spot of the radio wave sensor 10 due to indoor structures or the like, the living body detection device 1 can detect a living body in a room by taking advantage of the phenomenon in which radio waves from the radio wave sensor 10 are reflected by indoor structures or the like and irradiated onto the living body.

[0110] Furthermore, the target area of ​​the living body detection device 1 may be a columnar area having a height from the floor to the top of the seat back, with the bottom surface being the upper surface of the foot area, which is the floor surface at the foot of the seat, and the top surface being the upper surface of the seat, which is the surface including the seat surface when the seat is moved to the top of the seat back. This allows the living body detection device 1 to detect a living body present below the seat surface, such as a child crawling under the seat surface.

[0111] Furthermore, according to the first embodiment, in the living body detection device 1, the detection unit 104 detects the presence of a living body in a room when the distance to the object detected by the radio wave sensor 10 is equal to or greater than the first distance and equal to or less than a fourth distance obtained by adding the second distance and the third distance. Therefore, the living body detection device 1 can detect a living body present in a room. Even if a living body is present in a blind spot of the radio wave sensor 10 due to a structure or the like in the room, the living body detection device 1 can detect the living body in the room by utilizing the phenomenon in which radio waves from the radio wave sensor 10 are reflected by the structure or the like in the room and irradiated onto the living body.

[0112] Furthermore, according to the first embodiment, in the living body detection device 1, the detection unit 104 may detect the presence of a living body in a room if the distance to the object detected by the radio wave sensor 10 is equal to or greater than the first distance and equal to or less than a fourth distance obtained by adding the second distance and the third distance, and if the reflected power information, speed information, or position information included in the living body information satisfies the living body detection conditions for detecting whether the object is a living body. This allows the living body detection device 1 to avoid erroneously detecting an object other than a living body as a living body.

[0113] Furthermore, according to the first embodiment, in the living body detection device 1, when the distance to the object detected by the radio wave sensor 10 is equal to or greater than the first distance and equal to or less than a fourth distance obtained by adding the second distance and the third distance, and when the sensor information is input to a first machine learning model that receives input of sensor information and outputs information indicating whether the object is a living body, the detection unit 104 may detect that a living body is present in the room if the sensor information is input to a first machine learning model that outputs information indicating whether the object is a living body. This allows the living body detection device 1 to avoid erroneously detecting an object other than a living body as a living body.

[0114] Furthermore, according to the first embodiment, in the living body detection device 1, the detection unit 104 may determine that the living body is a person requiring assistance if the reflected power information, velocity information, or position information included in the living body information satisfies a condition for determining whether the object is a person requiring assistance. This allows the living body detection device 1 to provide a detection result indicating whether a living body is present in a room in a manner that prevents unnecessary alarms from being output.

[0115] Furthermore, according to the first embodiment, in the living body detection device 1, the detection unit 104 may input the sensor information to a second machine learning model that receives the sensor information and outputs information indicating whether the object is a person requiring assistance, and when the detection unit 104 obtains information indicating that the object is a person requiring assistance, it may determine that the living body is a person requiring assistance. This allows the living body detection device 1 to provide a detection result indicating whether or not a living body is present in a room in a manner that prevents unnecessary alarms from being output.

[0116] Furthermore, according to the first embodiment, the living body detection device 1 can be configured to include an output unit 105 that outputs a detection result indicating the presence of a living body in the room when the detection unit 104 detects the presence of a living body in the room. This allows the living body detection device 1 to provide a detection result indicating the presence of a living body in the room.

[0117] Furthermore, according to the first embodiment, the living body detection device 1 can be configured to include the output unit 105 that outputs a detection result indicating that a person requiring care is present in the room when the detection unit 104 determines that the living body is a person requiring care. This allows the living body detection device 1 to provide a detection result indicating that a person requiring care is present in the room.

[0118] Furthermore, according to the first embodiment, the radio wave sensor 10 includes a transmitting antenna Tx that radiates radio waves toward an indoor area, a receiving antenna Rx that receives reflected waves of the radio waves radiated from the transmitting antenna Tx, a radio wave transmitting / receiving unit 19 that radiates radio waves from the transmitting antenna Tx and acquires a received signal based on the reflected waves from the receiving antenna Rx, an A / D conversion circuit 17 that converts the received signal acquired by the radio wave transmitting / receiving unit 19 from an analog signal to a digital signal, a signal processing unit 18 that generates sensor information based on the digital signal converted by the A / D conversion circuit 17, a sensor information acquiring unit 101 that acquires the sensor information, and the sensor information acquired by the sensor information acquiring unit 101. The radio wave sensor 10 can be configured to include a detection unit 104 that detects whether a living organism is present in a room based on a first distance from the position of the radio wave sensor 10 to a first target point, which is a point on the top surface of a columnar target area having a height in the height direction of the seat and is the closest point to the position of the radio wave sensor 10, a second distance from the position of the radio wave sensor 10 to a second target point, which is a point on the top surface of the target area and is the farthest point from the position of the radio wave sensor 10 relative to the first target point, and a third distance from the second target point to a third target point, which is the farthest point in the target area from the second target point. Therefore, the radio wave sensor 10 can detect a living organism present in a room. Even if a living organism is present in a blind spot of the radio wave sensor 10 due to a structure or the like in the room, the radio wave sensor 10 can detect the living organism by utilizing the phenomenon in which radio waves from the radio wave sensor 10 are reflected by a structure or the like in the room and irradiated onto the living organism.

[0119] Furthermore, according to the first embodiment, the radio wave transmitter / receiver 19 can be configured to control the radiation range of radio waves in the radio wave sensor 10. This allows the radio wave sensor 10 to minimize the amount of radio waves radiated from the transmitting antenna Tx that are reflected by an indoor structure or a living body seated on the surface of another seat and then irradiated onto the living body.

[0120] Furthermore, according to the first embodiment, the biological detection system 1000 includes a radio wave sensor 10 having a transmitting antenna Tx that radiates radio waves toward an indoor area, a receiving antenna Rx that receives reflected waves of the radio waves radiated from the transmitting antenna Tx, a radio wave transmitting / receiving unit 19 that radiates radio waves from the transmitting antenna Tx and acquires a received signal based on the reflected waves from the receiving antenna Rx, an A / D conversion circuit 17 that converts the received signal acquired by the radio wave transmitting / receiving unit 19 from an analog signal to a digital signal, and a signal processing unit 18 that generates sensor information based on the digital signal converted by the A / D conversion circuit 17; a sensor information acquiring unit 101 that acquires sensor information from the radio wave sensor 10; The living body detection device 1 can be configured to include a detection unit 104 that detects the presence or absence of a living body in a room based on the sensor information obtained by the measurement, a first distance from the position of the radio wave sensor 10 to a first target point, which is a point on the top surface of a columnar target area having a height in the height direction of the seat and is the closest point to the position of the radio wave sensor 10, a second distance from the position of the radio wave sensor 10 to a second target point, which is a point on the top surface of the target area and is the farthest point from the position of the radio wave sensor 10 relative to the first target point, and a third distance from the second target point to a third target point, which is the farthest point in the target area from the second target point. Therefore, the living body detection system 1000 can detect a living body present in a room. The living body detection system 1000 can detect a living body in a room by utilizing the phenomenon in which radio waves from the radio wave sensor 10 are reflected by indoor structures and irradiated onto the living body, even if the living body is present in a blind spot of the radio wave sensor 10 due to indoor structures and the like.

[0121] Furthermore, according to the first embodiment, the radio wave transmitter / receiver 19 can be configured to control the radiation range of radio waves in the radio wave sensor 10 of the living body detection system 1000. This allows the living body detection system 1000 to minimize the radio waves radiated from the transmitting antenna Tx from being reflected by an indoor structure or a living body seated on the seat of another seat and then being irradiated with the living body.

[0122] Any of the components of the embodiments may be modified or omitted.

[0123] A living organism detection device according to the present disclosure is applicable to a living organism detection device that detects a living organism present in a room.

[0124] 1 Biodetection device, 101 Sensor information acquisition unit, 102 Area setting unit, 103 Distance calculation unit, 104 Detection unit, 105 Output unit, 10 Radio wave sensor, Tx Transmitting antenna, Rx Receiving antenna, 13 Radio wave sensor circuit unit, 14 High frequency signal generating circuit, 15 Radio wave transmitting unit, 15-1 Transmitting circuit, 16 Radio wave receiving unit, 16-1 Receiving circuit, 17 A / D conversion circuit, 18 Signal processing unit, 1000 Biodetection system, 1001 Processing circuit, 1002 Input interface device, 1003 Output interface device, 1004 Processor, 1005 Memory.

Claims

1. a sensor information acquisition unit that acquires sensor information generated based on a reflected wave of a radio wave emitted by a radio wave sensor toward an indoor area including at least a seat present in the indoor area and reflected by an object in the indoor area; a detection unit that detects whether or not a living body is present in the room based on the sensor information acquired by the sensor information acquisition unit, a first distance from the position of the radio wave sensor to a first target point that is a point on the upper surface of a columnar target area having a height in the height direction of the seat and is a point located closest to the position of the radio wave sensor, a second distance from the position of the radio wave sensor to a second target point that is a point on the upper surface of the target area and is a point located farthest from the position of the radio wave sensor than the first target point, and a third distance from the second target point to a third target point that is a point located farthest from the second target point in the target area. A biological detection device comprising:

2. a region setting unit that sets the target region, the first target point, the second target point, and the third target point based on the sensor information acquired by the sensor information acquisition unit; a distance calculation unit that calculates the first distance, the second distance, and the third distance.

2. The biological detection device according to claim 1,

3. The target area is a columnar area having a bottom surface that is a seat top surface including the seat surface of the seat and a top surface that is the seat top surface moved to the top end of the backrest of the seat, the columnar area having a height equal to the height of the backrest of the seat.

3. The biological detection device according to claim 1 or 2.

4. The target area is a columnar area having a bottom surface which is the floor surface of the foot area corresponding to the seat and a top surface which is the seat top surface which is the surface including the seat surface of the seat moved to the top end of the backrest of the seat, the columnar area having a height from the floor surface to the top end of the backrest of the seat.

3. The biological detection device according to claim 1 or 2.

5. the sensor information includes position information indicating a distance to the object detected by the radio wave sensor, The detection unit is When the distance to the object detected by the radio wave sensor is equal to or greater than the first distance and equal to or less than a fourth distance obtained by adding the second distance and the third distance, the living body is detected to be present in the room.

2. The biological detection device according to claim 1,

6. the sensor information includes reflected power information indicating the signal strength of the reflected wave, speed information indicating the speed of the object detected by the radio wave sensor, or position information indicating the distance and angle of the object detected by the radio wave sensor; The detection unit is When the distance to the object detected by the radio wave sensor is equal to or greater than the first distance and equal to or less than a fourth distance obtained by adding the second distance and the third distance, and when the reflected power information, the speed information, or the position information satisfies a living body detection condition for detecting whether the object is a living body, the living body is detected to be present in the room.

2. The biological detection device according to claim 1,

7. The detection unit is When the distance to the object detected by the radio wave sensor is equal to or greater than the first distance and equal to or less than a fourth distance obtained by adding the second distance and the third distance, and when the sensor information is input to a first machine learning model that receives the sensor information and outputs information indicating whether the object is the living body and obtains information that the object is the living body, the presence of the living body is detected in the room.

2. The biological detection device according to claim 1,

8. The detection unit determines whether the living body is a person who requires care and is unable to go outside the room on his / her own, based on the sensor information.

2. The biological detection device according to claim 1,

9. the sensor information includes reflected power information indicating the signal strength of the reflected wave, speed information indicating the speed of the object detected by the radio wave sensor, or position information indicating the distance and angle of the object detected by the radio wave sensor; The detection unit is When the reflected power information, the velocity information, or the position information satisfies a condition for determining whether the object is the person requiring assistance, the living body is determined to be the person requiring assistance.

9. The biological detection device according to claim 8.

10. The detection unit is The sensor information is input to a second machine learning model that outputs information indicating whether the object is the person requiring assistance, and when information indicating that the object is the person requiring assistance is obtained, the living body is determined to be the person requiring assistance.

9. The biological detection device according to claim 8.

11. an output unit that outputs a detection result indicating that the living body is present in the room when the detection unit detects that the living body is present in the room; The biological detection device according to claim 1 ,

12. an output unit that outputs a detection result indicating that the person requiring assistance is present in the room when the detection unit determines that the living body is the person requiring assistance; The biological detection device according to claim 8 ,

13. The interior of the vehicle is a passenger compartment of a vehicle, and the seat is a front seat or a rear seat in the passenger compartment.

2. The biological detection device according to claim 1,

14. The biological detection device according to claim 1 , a transmitting antenna that radiates the radio waves toward the indoor area; a receiving antenna for receiving the reflected wave of the radio wave radiated from the transmitting antenna; a radio wave transmitting / receiving unit that radiates the radio waves from the transmitting antenna and obtains a reception signal based on the reflected waves from the receiving antenna; an A / D conversion circuit that converts the received signal acquired by the radio wave transmitting / receiving unit from an analog signal to a digital signal; A signal processing unit that generates the sensor information based on the digital signal converted by the A / D conversion circuit A radio wave sensor comprising:

15. The radio wave transmitting and receiving unit controls a radiation range of the radio wave.

15. The radio wave sensor according to claim 14.

16. The biological detection device according to claim 1 , a transmitting antenna that radiates the radio waves toward the indoor area; a receiving antenna for receiving the reflected wave of the radio wave radiated from the transmitting antenna; a radio wave transmitting / receiving unit that radiates the radio waves from the transmitting antenna and obtains a reception signal based on the reflected waves from the receiving antenna; an A / D conversion circuit that converts the received signal acquired by the radio wave transmitting / receiving unit from an analog signal to a digital signal; a signal processing unit that generates the sensor information based on the digital signal converted by the A / D conversion circuit, A biological detection system comprising:

17. The radio wave transmitting and receiving unit controls a radiation range of the radio wave.

17. The biological detection system according to claim 16.

18. a step in which a sensor information acquisition unit acquires sensor information generated based on a reflected wave of a radio wave emitted by a radio wave sensor toward an indoor area including at least a seat present in the indoor area and reflected by an object in the indoor area; a detection unit detecting whether or not the living body is present in the room based on the sensor information acquired by the sensor information acquisition unit, a first distance from the position of the radio wave sensor to a first target point, which is a point on the upper surface of a columnar target area having a height in the height direction of the seat and is a point located closest to the position of the radio wave sensor, a second distance from the position of the radio wave sensor to a second target point, which is a point on the upper surface of the target area and is a point located farthest from the position of the radio wave sensor than the first target point, and a third distance from the second target point to a third target point, which is a point located farthest from the second target point in the target area. A living body detection method comprising: