Occupant detection method and occupant detection device

Abstract

In a vehicle (2) comprising, in a cabin, a wave detection sensor (20) that transmits a detection wave and detects the detection wave reflected by an object, and a reflector (60) that reflects the detection wave, a processor (100) acquires, from the wave detection sensor (20), first detection information in which a first detection wave is detected, and detects an occupant on the basis of the first detection information, and the first detection wave is a detection wave transmitted from the wave detection sensor (20) and reflected by the object via the reflector (60).

Description

Occupant detection method and occupant detection device

[0001] The present invention relates to an occupant detection method and an occupant detection device.

[0002] A technology is known that uses first data acquired by a first sensor to determine whether or not the occupant is an infant, uses second data acquired by a second sensor to determine whether or not the occupant is an infant, estimates whether or not an infant is on board based on the determination result, and outputs the estimation result (Patent Document 1).

[0003] International Publication No. 2021 / 124548

[0004] However, the technology described in Patent Document 1 uses two sensors installed in the vehicle cabin to detect occupants in blind spots, such as areas hidden by seats. Therefore, if there is only one sensor in the vehicle cabin, there is a problem in that occupants in blind spots from the sensor cannot be detected with high accuracy.

[0005] The problem that the present invention aims to solve is to provide an occupant detection method and an occupant detection device that can accurately detect occupants in a blind spot from a sensor installed in the passenger compartment of a vehicle when the sensor detects the interior of the passenger compartment.

[0006] The present invention solves the above problem in a vehicle equipped with a detection sensor inside the passenger compartment that emits a detection wave and detects the detection wave reflected by an object, and a reflector that reflects the detection wave, by obtaining first detection information from the detection sensor that detects a first detection wave, and detecting an occupant based on the first detection information, wherein the first detection wave is a detection wave that is emitted from the detection sensor and reflected by an object via a reflector.

[0007] According to the present invention, when one sensor for detecting the interior of the vehicle is installed in the vehicle interior, an occupant in a blind spot from the sensor can be detected with high accuracy.

[0008] Fig. 1 is a block diagram showing the configuration of an occupant detection device according to this embodiment. Fig. 2 is a plan view of the interior of a vehicle equipped with the occupant detection device according to this embodiment. Fig. 3 is a schematic view of the interior of a vehicle equipped with the occupant detection device according to this embodiment, as seen from the side. Fig. 4 is a plan view of the interior of a vehicle equipped with the occupant detection device according to this embodiment. Fig. 5 is a diagram showing an example of a flowchart of control processing of an occupant detection method according to this embodiment.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the vehicle will be described on the assumption that the steering wheel is installed on the left seat of the vehicle (the driver's seat is on the left side). However, the present invention is not limited to this, and the vehicle may be a vehicle that the steering wheel is installed on the right seat of the vehicle (the driver's seat is on the right side). In this case, the left and right in the following description will be interpreted as symmetrical.

[0010] An occupant detection device according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a block diagram showing the configuration of the occupant detection device according to this embodiment. A vehicle 2 includes an occupant detection device 10, a detection sensor 20, an exterior sensor 30, an on-board communication device 40, and an output device 50. These devices are connected via CAN communication or other on-board LAN, and can transmit and receive information to and from each other. The vehicle 2 also includes a reflector 60 inside the vehicle cabin. The occupant detection device 10 acquires detection information from the detection sensor 20 and detects an occupant in the vehicle cabin of the vehicle 2 based on the acquired detection information.

[0011] Vehicle 2 is a vehicle that has multiple seat rows inside the vehicle cabin. Each seat row has one or more seats lined up along the left-right direction (vehicle width direction) of vehicle 2. The seats face the front (direction of travel) of vehicle 2. In other words, when an occupant sits in a seat, the occupant sits in the seat facing the front of vehicle 2. Multiple seat rows inside the vehicle cabin are lined up along the fore-and-aft direction of vehicle 2. For example, there are three seat rows. However, there may be two seat rows, or four or more seat rows.

[0012] In the following description, an example will be described in which the seat rows in the passenger compartment of the vehicle 2 include three seat rows aligned along the longitudinal direction of the vehicle 2, i.e., a first seat row, a second seat row, and a third seat row. The first seat row is the seat row located furthest forward among the seat rows in the passenger compartment. In the first seat row, multiple seats are aligned in the left-right direction of the vehicle 2 toward the front of the vehicle 2. In other words, the backrests of each seat included in the first seat row face the front of the vehicle 2. The first seat row includes a driver's seat in which the driver sits and a passenger seat adjacent to the driver's seat. The second seat row is a seat row further rearward than the first seat row and is the second seat row from the front of the vehicle. In the second seat row, multiple seats are aligned in the left-right direction of the vehicle 2 toward the front of the vehicle 2. For example, the second seat row includes two seats. These seats are respectively located directly behind the driver's seat and passenger seat in the first seat row. Note that the second seat row may also include three seats.

[0013] The third seat row is the third seat row that is located furthest to the rear of the vehicle among the seat rows in the vehicle cabin, and is located further rearward than the second seat row. The third seat row has multiple seats lined up in the left-right direction of the vehicle 2 facing the front of the vehicle 2. For example, the third seat row includes three seats. The third seat row may also have two seats. In this embodiment, the seat rows in the vehicle cabin of the vehicle 2 are three seat rows, but the present invention is not limited to this, and may also have two seat rows, or four or more seat rows.

[0014] The interior of vehicle 2 is composed of a space in front of the first seat row and a space in rear of the first seat row. Specifically, the space in front of the first seat row is the space in front of the seat backs of the first seat row. The space in rear of the second seat row is the space in rear of the seat backs of the first seat row. In the space in front of the first seat row, occupants sit in the seats in the first seat row (driver's seat and passenger seat). In the space in rear of the first seat row, occupants sit in the seats in the second and third seat rows.

[0015] Here, the seat arrangement in the cabin of the vehicle 2 will be described using FIG. 2 . FIG. 2 shows a plan view of the interior of a vehicle equipped with an occupant detection device according to this embodiment. As shown in FIG. 2 , the front-to-rear direction of the vehicle 2 is defined as the X axis, and the left-to-right direction of the vehicle 2 is defined as the Y axis. The vehicle 2 includes a driver's seat S11, a passenger seat S12, a first rear seat S21, a second rear seat S22, a third rear seat S31, a fourth rear seat S32, and a fifth rear seat S33. The driver's seat S11 and the passenger seat S12 are seats in the first seat row. The first rear seat S21 and the second rear seat S22 are seats in the second seat row. The third rear seat S31, the fourth rear seat S32, and the fifth rear seat S33 are seats in the third seat row. The cabin of the vehicle 2 is composed of a space FS located forward of the first seat row and a space BS located rearward of the first seat row.

[0016] As shown in Figure 2, the space FS at the front of the vehicle and the space BS at the rear of the vehicle are separated by the seatbacks of the seats in the first seat row. That is, the space FS at the front of the vehicle is the space in front of the seatbacks of the seats in the first seat row (driver's seat S11 and passenger seat S12). The space BS at the rear of the vehicle is the space in rear of the seatbacks of the seats in the first seat row (driver's seat S11 and passenger seat S12). The space BS at the rear of the vehicle is made up of the space in front of the seatbacks of the seats in the second seat row (first rear seat S21 and second rear seat S22) and the space in rear of the seatbacks of the seats in the second seat row (first rear seat S21 and second rear seat S22).

[0017] The detection sensor 20 is a sensor installed in the passenger compartment of the vehicle 2 that emits detection waves and detects the detection waves reflected by objects. The detection waves are, for example, electromagnetic waves such as millimeter waves and microwaves, or sound waves such as ultrasonic waves. In the following description, the detection waves will be described as microwaves. Microwaves have a frequency of 10 to 60 GHz, and examples of such waves include Wi-Fi (registered trademark). The detection sensor 20 emits detection waves into the passenger compartment. For example, the detection sensor 20 emits the detection waves in the direction of a reflector 60 in the passenger compartment and / or in the direction of each seat in the passenger compartment. The detection sensor 20 may emit detection waves in all directions within the passenger compartment, centered around the position of the detection sensor 20. Detection information obtained by the detection sensor 20 detecting the detection waves is output to the occupant detection device 10. The detection information includes information on the frequency of the detected detection waves. Furthermore, the detection sensor 20 measures the distance between the detection sensor 20 and the object from which the detection wave is reflected, based on the results of transmission and reception of the detection wave. The detection information includes distance information indicating the distance between the detection sensor 20 and the object from which the detection wave is reflected.

[0018] In this embodiment, the detection sensor 20 is located in an upper portion of the space rearward of the first seat row. That is, the detection sensor 20 is located rearward of the seat backs of the first seat row. The upper portion of the space refers to above the seats in the space, for example, the ceiling of the vehicle interior. As an example, the detection sensor 20 is installed in the ceiling of the space between the seat backs of the first seat row and the seat backs of the second seat row. More specifically, the detection sensor 20 is installed in the ceiling above the seats in the second seat row. The position of the detection sensor 20 in the left-right direction is, for example, the center of the vehicle 2 in the left-right direction. For example, if the second seat row has two seats in the left-right direction, the center of the vehicle 2 in the left-right direction is between the left seat and the right seat in the second seat row. For example, if the second seat row has three seats in the left-right direction, the center of the vehicle 2 in the left-right direction is the position of the center seat in the second seat row. The above-described installation position of the wave detection sensor 20 is an example and is not limited to this.

[0019] When the detection sensor 20 is installed in the above-described installation position, the detection wave emitted from the detection sensor 20 is directly reflected by an occupant in the space behind the vehicle (i.e., an occupant in a seat in the second seat row) and received by the detection sensor 20. Meanwhile, in the space ahead of the first seat row, a blind spot exists for the detection sensor 20, such as an area hidden by the seats in the first seat row. Because the seat backs contain metal, such as springs, the detection wave has poor transparency. Therefore, the detection wave cannot be directly reflected by an occupant in the space ahead of the vehicle, i.e., an occupant in a seat in the first seat row. In particular, if the occupant is small, such as a child, the occupant is hidden in the blind spot from the detection sensor 20. In this embodiment, even in such a situation, a single sensor installed in the vehicle cabin can accurately detect a vehicle occupant in the blind spot from the sensor.

[0020] For example, as shown in FIG. 2 , the detection sensor 20 is located in the space BS at the rear of the vehicle. Specifically, the detection sensor 20 is installed on the ceiling above a position between the backrest of the left seat (rear seat S21) in the second seat row and the backrest of the right seat (rear seat S22). The detection sensor 20 installed in this position can directly irradiate a detection wave toward an occupant sitting in a seat in the second seat row (e.g., rear seat S22) and detect the detection wave reflected from the occupant. However, the detection sensor 20 cannot directly irradiate a detection wave toward an occupant sitting in seat S11 because the backrest of a seat in the first seat row (e.g., driver's seat S11) is an obstacle.

[0021] In this embodiment, when the detection sensor 20 is installed in a space BS rearward of the first seat row, the reflector 60 is located in a space FS forward of the first seat row. The detection wave emitted from the detection sensor 20 is irradiated toward the seats in the first seat row via the reflector 60. For example, the reflector 60 is installed in a position within the space in the front of the vehicle where the detection wave can be directly emitted from the detection sensor 20. That is, the reflector 60 is installed in a position where no other objects (obstacles such as seat backs) are present on a line connecting the positions of the reflector 60 and the detection sensor 20. The orientation of the reflector 60 is adjusted so that the detection wave emitted from the detection sensor 20 toward the reflector 60 is reflected toward the seats in the first seat row. For example, the orientation of the reflector 60 is adjusted so that the direction of travel of the detection wave is deflected toward a position corresponding to the height of the occupant's chest. As a result, even if the detection wave emitted from the detection sensor 20 cannot be reflected directly to the occupant, the detection wave can be reflected to the occupant via the reflector 60.

[0022] As an example, the reflector 60 is installed in the upper part of the space in the front of the vehicle. The upper part of the space in the front of the vehicle is a position higher than the height of the backrest of the seat in the first seat row. The height of the backrest of the seat is the height from the floor of the vehicle 2 to the headrest of the seat. For example, the reflector 60 is installed near the rearview mirror located at the top center of the front window of the vehicle 2. The reflector 60 may also be installed on the ceiling of the space in the front of the vehicle.

[0023] The installation position of the reflector 60 is not limited to the above-described installation position. The reflector 60 may be located in any position within the space in front of the vehicle where the detection wave can be directly emitted from the detection sensor 20. For example, the reflector 60 may be installed on pillars (A-pillars) located on the left and right sides of the front window of the vehicle 2. For example, the reflector 60 is installed on the inner surface of the pillar. The reflector 60 may be installed in one location or in multiple locations. Note that in the present embodiment, the detection sensor 20 is installed in a space rearward of the first seat row, and the reflector 60 is installed in a space in front of the first seat row. However, the present invention is not limited to this. The detection sensor 20 may be installed in a space in front of the first seat row, and the reflector 60 may be installed in a space rearward of the first seat row. In this case, the detection sensor 20 reflects the detection wave directly to the occupants in the first seat row, and reflects the detection wave via the reflector 60 to the occupants in the second seat row. Here, an example of the installation position of the reflector 60 will be described using FIG. 3 . FIG. 3 is a schematic diagram of the interior of a vehicle equipped with an occupant detection device according to this embodiment, viewed from the side. In FIG. 3 , reflectors 60a, 60b, and 60c are installed in the vehicle 2. The reflector 60a is installed near the rearview mirror located at the top center of the front window of the vehicle 2. The reflector 60b is installed on pillars (A-pillars) located on the left and right sides of the front window of the vehicle 2. The reflector 60c is installed on the ceiling portion of the space in front of the vehicle. Each reflector 60, like the reflector 60a shown in FIG. 3 , reflects the detection wave Dw irradiated from the detection sensor 20 toward the seat S. Note that, although the reflectors 60a, 60b, and 60c are installed in FIG. 3 , this is not a limitation in this embodiment. It is sufficient that at least one of these reflectors 60 is installed. The reflectors 60 may be installed at positions other than these reflectors 60 as long as they can reflect the detection waves emitted from the detection sensors 20 in the direction of the seats.

[0024] In the example of FIG. 2 , the reflector 60 is installed near the rearview mirror located at the top center of the front window of the vehicle 2. The orientation of the reflector 60 is adjusted so that the detection wave Dw1 emitted from the detection sensor 20 is reflected by the reflector 60 and irradiated toward the driver's seat S11. As a result, the detection wave emitted from the detection sensor 20 is reflected by the occupant sitting in the driver's seat S11 via the reflector and is received by the detection sensor 20 again via the reflector. In addition, in this embodiment, the space FS at the front of the vehicle and the space BS at the rear of the vehicle may be separated by the position of the occupant sitting in the seat in the first seat row. That is, the reflector 60 may be installed further forward than the position of the occupant's chest when the occupant sits in the seat in the first seat row. If the reflector 60 is located directly beside the occupant, when the detection wave is irradiated via the reflector 60 toward the occupant's chest from directly beside the occupant, it may hit the occupant's ribs and not pass through. Therefore, the reflector 60 is installed on the vehicle front side relative to the position of the occupant's chest.

[0025] 2, the reflector 60 reflects the detection wave toward the driver's seat S11, but the reflector 60 may be configured to reflect the detection wave toward each seat in the first seat row (the driver's seat S11 and the passenger seat S12). In this embodiment, by installing the detection sensor 20 and the reflector 60 as shown in FIG. 2, it is unlikely that an object outside the vehicle cabin will be present in the direction in which the reflector 60 is located, i.e., in the direction of travel of the vehicle 2, and therefore it is possible to suppress the occurrence of ghosts in occupant detection (a phenomenon in which a person is detected as being present in a place in the vehicle cabin where no person is present).

[0026] Furthermore, as shown in FIG. 2 , when the seat rows in the passenger compartment of the vehicle 2 include three seat rows aligned along the longitudinal direction of the vehicle 2, the reflector 60 need not be located in the space in front of the vehicle but may be located in the space behind the second seat row, i.e., in the space between the backrests of the seats in the second seat row and the backrests of the seats in the third seat row. For example, the reflector 60 may be installed on the ceiling above the seats in the third seat row or on the left and right interior surfaces of the passenger compartment. As a result, for example, when the detection sensor 20 is installed above a seat in the second seat row, even if the backrests of the seats in the second seat row obstruct the detection wave from directly irradiating the occupant in the third seat row, the detection sensor 20 can reflect the detection wave to the occupant in the third seat row via the reflector 60. Furthermore, in this embodiment, a reflector 60 may be installed for each seat. The orientation of the reflectors 60 corresponding to the respective seats is adjusted so that the direction of the detection wave reflected by the reflectors 60 is deflected in the direction of the corresponding seat.

[0027] The reflector 60 is an object different from the detection target in the vehicle cabin. The detection target is an occupant or a seat. The reflector 60 is an object that deflects the traveling direction of the detection wave emitted from the detection sensor 20 toward the reflector 60 in the direction of the detection target (i.e., a seat in the vehicle cabin). The reflector 60 is, for example, a plate-shaped member. The reflector 60 is made of a member that reflects the detection wave, such as a mirror or glass. For example, the surface of the reflector 60 is coated with a reflective material such as a mirror or glass. The outer shape of the reflector 60 has a curved surface, such as a circular, elliptical, or spherical shape. The reflector 60 may have a surface treated to widen the viewing angle.

[0028] The detection sensor 20 detects a first detection wave. The first detection wave is a detection wave transmitted from the detection sensor 20 and reflected by an object via the reflector 60. For example, the detection sensor 20 transmits a detection wave toward the reflector 60 and detects the detection wave reflected from the reflector 60 as the first detection wave. The detection wave reflected from the reflector 60 is a detection wave from the direction in which the reflector 60 is located. The first detection wave is also referred to as an indirectly reflected wave. The orientation of the reflector 60 is adjusted so as to deflect the traveling direction of the detection wave reflected from the reflector 60 toward the seat in the first seat row (driver's seat or passenger seat). Therefore, the first detection wave is a detection wave reflected from the seat in the first seat row or an occupant occupying that seat. In other words, when an occupant is present in the seat, the first detection wave is a detection wave reflected from the occupant, and when an occupant is not present in the seat, the first detection wave is a detection wave reflected from the seat. The first detection wave is a detection wave reflected by an object other than an occupant placed on the seat. The detection sensor 20 detects the first detection wave and outputs the first detection information to the occupant detection device 10.

[0029] The detection sensor 20 also detects a second detection wave. The second detection wave is a detection wave transmitted from the detection sensor 20 and reflected by an object without passing through the reflector 60. That is, the second detection wave is a detection wave transmitted from the detection sensor 20 that is directly reflected by an object other than the reflector 60 and received by the detection sensor 20. A detection wave directly reflected by an object other than the reflector 60 and received by the detection sensor 20 is, for example, a detection wave from a direction other than the direction in which the reflector 60 is located. The second detection wave is also referred to as a directly reflected wave. The second detection wave is a detection wave reflected by a seat to which the detection sensor 20 can directly irradiate the detection wave or by an occupant seated in the seat. That is, when an occupant is present in the seat, the second detection wave is a detection wave directly reflected by the occupant. When an object other than an occupant is placed on the seat, the second detection wave is a detection wave directly reflected by the seat. In this embodiment, the detection sensor 20 transmits detection waves toward the seats in the second seat row and / or the third seat row, and detects the detection waves reflected by the seats or occupants as second detection waves. Second detection information obtained by the detection sensor 20 detecting the second detection waves is output to the occupant detection device 10. Note that in this embodiment, the detection of the second detection waves is not an essential component, and may be included in the appropriate component as needed.

[0030] Furthermore, in the present embodiment, when the detection sensor 20 is activated, the detection sensor 20 may emit a detection wave into the surrounding area and detect the detection wave reflected by an object. For example, the detection sensor 20 is activated when a user of the vehicle 2 gets out of the vehicle 2. The detection sensor 20 is also activated when a user of the vehicle 2 turns on the activation switch of the detection sensor 20 or when the detection sensor 20 receives an activation instruction from the occupant detection device 10. The detection wave emitted at the time of activation is for determining the presence or absence of an obstruction and is different from the detection wave emitted for occupant detection. When the detection sensor 20 determines that the object is not obstructed by an obstruction, it emits a detection wave for occupant detection. Note that, in the present embodiment, emitting a detection wave for determining the presence or absence of an obstruction is not a required configuration and may be included as needed.

[0031] The exterior sensor 30 is a sensor installed on an exterior wall surface outside the cabin of the vehicle 2 and detects the area outside the cabin of the vehicle 2. Detection targets of the exterior sensor 30 include exterior objects located outside the cabin. The exterior objects are objects located around the vehicle 2, such as humans, such as pedestrians. The exterior sensor 30 may be, for example, a camera equipped with an imaging element such as a CCD or CMOS, installed on the exterior wall surface of the vehicle 2. The cameras include a front camera, left and right side cameras, and a rear camera. The left and right side cameras are installed at predetermined positions on the exterior left or right side of the vehicle 2. For example, the left and right side cameras are installed on the left and right side mirrors, respectively. The exterior sensor 30 captures images of the area around the vehicle 2 using the cameras. The exterior detection information may be an image of the area around the vehicle 2, or a bird's-eye view image (a so-called around-view monitor image) converted from the image.

[0032] The exterior sensor 30 may be a combination of radars such as millimeter-wave radar, laser radar, and ultrasonic radar, or sonar. For example, these radars or sonars are installed on the exterior wall surfaces of the sides and rear of the vehicle 2 to detect objects outside the vehicle cabin that exist around the vehicle 2. The exterior detection information detected by the exterior sensor 30 is output to the occupant detection device 10. In this embodiment, even if one sensor is installed inside the vehicle cabin, the accuracy of occupant detection can be improved by using the existing sensor outside the vehicle cabin without installing an additional sensor inside the vehicle cabin.

[0033] The occupant detection device 10 performs occupant detection at a predetermined timing. The predetermined timing is when the occupant detection device 10 is activated by the user of the vehicle 2. The occupant detection device 10 may be activated when the vehicle 2 is stopped (when the vehicle 2 is stopped or parked) or when the user of the vehicle 2 leaves the vehicle 2. As shown in FIG. 1 , the occupant detection device 10 includes a processor 100. The processor 100 is a computer including a ROM storing a program for performing occupant detection within the passenger compartment of the vehicle 2, a CPU as an operating circuit that functions as the occupant detection device 10 by executing the program stored in the ROM, and a RAM that functions as an accessible storage device.

[0034] The processor 100 includes, as functional blocks, an acquisition unit 101, a detection unit 102, and an output unit 103. The processor 100 of this embodiment executes each function through cooperation between the software for realizing each of the above functions or executing each process and the hardware described above. Note that in this embodiment, the functions of the processor 100 are divided into three blocks, and the functions of each functional block are described, but the functions of the processor 100 do not necessarily have to be divided into three blocks, and may be divided into two or less functional blocks, or four or more functional blocks.

[0035] The acquisition unit 101 executes an acquisition process to acquire detection information of a detection wave detected by the detection sensor 20 from the detection sensor 20. In the acquisition process, the acquisition unit 101 acquires first detection information of a first detection wave detected from the detection sensor 20. The first detection wave is a detection wave that is transmitted from the detection sensor 20 and reflected by an object via the reflector 60.

[0036] Furthermore, in the acquisition process, the acquisition unit 101 acquires second detection information indicating the detection of a second detection wave from the detection sensor 20. The second detection wave is a detection wave that is transmitted from the detection sensor 20 and reflected by an object without passing through the reflector 60. In this embodiment, the acquisition unit 101 acquires the first detection information and / or the second detection information from the detection sensor 20 when a user of the vehicle 2 activates the occupant detection device 10. Furthermore, when the detection sensor 20 is activated, the acquisition unit 101 may acquire, from the detection sensor 20, detection information indicating the detection of the detection wave transmitted by the detection sensor 20 to the surroundings.

[0037] In the present embodiment, the acquisition unit 101 may also perform a process of determining the detection wave during the process of acquiring the first detection information. In the determination process, it is determined whether the detection wave detected by the detection sensor 20 is the first detection wave or a detection wave reflected by an object outside the vehicle cabin. Specifically, the acquisition unit 101 acquires detection information indicating the detection of the detection wave from the detection sensor 20. For example, the detection information is detection information indicating the detection of the detection wave from the direction in which the reflector 60 is located. The acquisition unit 101 acquires, from the exterior sensor 30, outside-vehicle detection information indicating the detection of an object outside the vehicle cabin that is present outside the vehicle cabin. Based on the detection information from the detection sensor 20 and the exterior detection information from the detection sensor 20, the acquisition unit 101 determines whether the detection wave detected by the detection sensor 20 is the first detection wave or a detection wave reflected by an object outside the vehicle cabin.

[0038] Specifically, the acquisition unit 101 first identifies the direction in which the detection sensor 20 received the detection wave from the detection information of the detection sensor 20. The acquisition unit 101 determines whether an object outside the vehicle cabin exists in the direction in which the detection sensor 20 received the detection wave based on the detection information outside the vehicle cabin. If the acquisition unit 101 determines that an object outside the vehicle cabin exists in the direction in which the detection sensor 20 received the detection wave, the acquisition unit 101 determines that the detection wave is a detection wave reflected by an object outside the vehicle cabin. If the acquisition unit 101 determines that no object outside the vehicle cabin exists in the direction in which the detection wave was received, the acquisition unit 101 determines that the detection wave is a first detection wave. Then, the acquisition unit 101 excludes detection waves reflected by objects outside the vehicle cabin from the detection waves detected by the detection sensor 20, and identifies detection waves other than those reflected by objects outside the vehicle cabin (detection waves determined to be first detection waves) as first detection waves. When the detection information from the detection sensor 20 is detection information that detects a detection wave from the direction in which the reflector 60 is located, the direction in which the detection wave was received is the direction in which the reflector 60 is located. In this case, the acquisition unit 101 determines whether or not an object outside the vehicle cabin is present in the direction in which the reflector 60 is located, based on the detection information outside the vehicle cabin. Note that in this embodiment, the process of determining the detection wave is not an essential component, and may be included in the appropriate component as needed.

[0039] Here, the process of determining a detection wave based on the detection information of the vehicle exterior sensor 30 will be described with reference to FIG. 4 . FIG. 4 shows a plan view of the interior of a vehicle equipped with an occupant detection device according to this embodiment. In FIG. 4 , as in FIG. 2 , the longitudinal direction of the vehicle 2 is defined as the X axis, and the lateral direction of the vehicle 2 is defined as the Y axis. In FIG. 4 , the vehicle exterior sensor 30 is installed in the vehicle 2. At this time, the detection sensor 20 detects the detection wave Dw2. The vehicle exterior sensor 30 detects an outside object Ob that exists outside the vehicle cabin. In the example of FIG. 4 , the acquisition unit 101 acquires detection information indicating the detection wave Dw2 from the detection sensor 20. The acquisition unit 101 also acquires outside detection information indicating the detection of the outside object Ob from the vehicle exterior sensor 30. The acquisition unit 101 determines that an object Ob outside the vehicle compartment is present in the direction from which the detection wave Dw2 is received based on the detection information from the detection sensor 20 and the detection information outside the vehicle compartment, and identifies the detection wave Dw2 as a detection wave reflected by the object Ob outside the vehicle compartment. This determination process can suppress the occurrence of ghosts in occupant detection.

[0040] The detection unit 102 executes a detection process to detect an occupant in the passenger compartment of the vehicle 2 based on the information acquired by the acquisition unit 101. In the detection process, the detection unit 102 detects an occupant based on first detection information. That is, the detection unit 102 detects an occupant in a blind spot from the detection sensor 20 (outside the detectable range of the detection sensor 20) based on the first detection information. An occupant in a blind spot from the detection sensor 20 is, for example, an occupant sitting in a seat in the first seat row. The detection unit 102 detects an occupant by determining whether an object that has reflected a detection wave is an occupant or an object other than an occupant based on the first detection information. An object other than an occupant is, for example, a seat. The first detection information includes information on the frequency of the first detection wave. When an occupant is seated in a seat, a Doppler effect occurs due to the occupant's breathing and / or heartbeat, causing the frequency of the first detection wave reflected from the occupant to fluctuate. The detection unit 102 detects the presence of an occupant from the difference between the frequency at which the first detection wave is transmitted and the frequency at which the first detection wave is received, based on the first detection information.

[0041] Furthermore, in the detection process, the detection unit 102 detects an occupant based on the second detection information. That is, the detection unit 102 detects an occupant within the detectable range of the detection sensor 20. An occupant within the detectable range of the detection sensor 20 is, for example, an occupant sitting in a seat in the second seat row. The detection unit 102 detects an occupant by determining, based on the second detection information, whether the object that reflected the detection wave is an occupant or an object other than an occupant. An example of an object other than an occupant is a seat. The second detection information includes information on the frequency of the second detection wave. When an occupant is seated in a seat, a Doppler effect occurs due to the occupant's breathing and / or heartbeat, causing the frequency of the second detection wave reflected from the occupant to fluctuate. The detection unit 102 detects an occupant based on the second detection information from the difference between the frequency at which the second detection wave is emitted and the frequency at which it is received. As described above, in the detection process, the detection unit 102 detects an occupant throughout the vehicle interior, including areas that are blind spots from the detection sensor 20, based on the first detection information and the second detection information.

[0042] As described above, in this embodiment, even when there is only one sensor in the vehicle interior, it is possible to accurately detect an occupant in a blind spot from the sensor, thereby preventing a false detection that an occupant is not present when there is an occupant in the blind spot. Therefore, since there is no need to install another sensor in the vehicle interior to detect a blind spot from the sensor, it is possible to reduce the number of sensors and thereby reduce costs.

[0043] The output unit 103 executes an output process to output information via the in-vehicle communication device 40 and / or the output device 50. The output information includes, for example, notification information indicating that an occupant is present in the vehicle cabin. In the output process, when the detection unit 102 detects an occupant, the output unit 103 outputs the notification information indicating that an occupant is present in the vehicle cabin via the in-vehicle communication device 40 and / or the output device 50.

[0044] In the present embodiment, the output unit 103 may determine whether the detection sensor 20 is shielded by a shielding object based on the detection information of the detection sensor 20 acquired by the acquisition unit 101. The shielding object is an object that shields the detection wave emitted from the detection sensor 20. For example, when the detection sensor 20 is activated, if the acquisition unit 101 acquires detection information indicating that the detection wave emitted from the detection sensor 20 into the surrounding area has been detected, the output unit 103 determines whether the detection sensor 20 is shielded by a shielding object based on distance information included in the acquired detection information. If the distance between the detection sensor 20 and the object that reflected the detection wave is equal to or shorter than a predetermined distance, the output unit 103 determines that the detection sensor 20 is shielded by a shielding object. The predetermined distance is, for example, a preset value, such as the distance between the detection sensor 20 and the seat (or an occupant in the seat). If the distance between the detection sensor 20 and the object that reflected the detection wave is equal to or less than a predetermined distance, the detected object is considered to be located in front of the seat, and in such a case, the detected object is determined to be not the seat but an obstruction in front of the seat that is blocking the detection wave. Furthermore, the output unit 103 may determine that the detection sensor 20 is obstructed by an obstruction if it cannot acquire detection information including distance information after emitting the detection wave.

[0045] The determination of whether the detection sensor 20 is shielded by an obstacle is not limited to a determination based on distance, but may also be a determination based on the time between the emission of a detection wave and its reception. The output unit 103 determines that the detection sensor 20 is shielded by an obstacle when the time between the emission of a detection wave by the detection sensor 20 and its reception is equal to or less than a predetermined time. The predetermined time is, for example, a preset value, and is the time between the emission of a detection wave by the detection sensor 20 and the detection wave being reflected by a seat and detected by the detection sensor 20.

[0046] If it is determined that the detection sensor 20 is shielded by an obstruction, the output unit 103 outputs notification information indicating that the detection sensor 20 is shielded by an obstruction via the in-vehicle communication device 40 and / or the output device 50. The output unit 103 may also determine that the detection sensor 20 is shielded by an obstruction when it is unable to detect a detection wave emitted toward the seat or the reflector 60, or when it is unable to detect any detection wave emitted into the vehicle interior.

[0047] The in-vehicle communication device 40 exchanges information with a terminal device (not shown) external to the vehicle 2 via wireless communication. The external terminal device is a portable mobile terminal such as a mobile phone or tablet terminal used by the user of the vehicle 2. The in-vehicle communication device 40 transmits notification information indicating that there is an occupant in the vehicle cabin to the external terminal device. The external terminal device outputs the received notification information to the user. For example, image information including the notification information is displayed, and audio information including the notification information is output. As a result, after the user of the vehicle 2 gets out of the vehicle 2 and leaves the vehicle 2, the user of the vehicle 2 can know that there is an occupant in the vehicle cabin via the terminal device carried by the user of the vehicle 2.

[0048] The output device 50 is a device for outputting information and providing the information to the occupants. The output device 50 may be an in-vehicle device, or may be a device mounted on a portable mobile terminal such as a mobile phone or tablet terminal used by the occupants. The output device 50 is a device for displaying image information, and is configured by a liquid crystal display, a projector, or the like. For example, the display is a meter panel or a head-up display. The output device 50 may also be a device for outputting audio information. For example, the output device 50 is configured by a speaker.

[0049] Next, an example of a procedure for executing the occupant detection method according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of a flowchart of a control process of the occupant detection method according to this embodiment, which is executed by the occupant detection device 10. In this embodiment, when a user of the vehicle 2 activates the occupant detection device 10, the control flow starts from step S101.

[0050] In step S101, the processor 100 acquires first detection information from the detection sensor 20. The first detection information is detection information obtained by detecting a first detection wave that is transmitted from the detection sensor 20 and reflected by an object via the reflector 60. In step S102, the processor 100 detects an occupant based on the first detection information. For example, the processor 100 detects the presence or absence of an occupant by determining whether the object that reflected the first detection wave is an occupant. In addition, in the present embodiment, the processor 100 may acquire the first detection information and the second detection information in step S101, and detect an occupant in the passenger compartment of the vehicle 2 based on the first detection information and the second detection information in step S102. That is, the processor 100 detects an occupant in a blind spot from the detection sensor 20 in the passenger compartment of the vehicle 2 based on the first detection information, and detects an occupant in the detection range of the detection sensor 20 in the passenger compartment of the vehicle 2 based on the second detection information.

[0051] As described above, in the occupant detection method and occupant detection device according to this embodiment, a processor detects an occupant in the passenger compartment of a vehicle. The vehicle includes a detection sensor that emits a detection wave and detects the detection wave reflected by an object, and a reflector that reflects the detection wave, inside the passenger compartment. The processor acquires first detection information from the detection sensor, which detects a first detection wave, and detects an occupant based on the first detection information. The first detection wave is a detection wave that is emitted from the detection sensor and reflected by an object via a reflector. This allows for accurate detection of an occupant in a blind spot of the sensor when one sensor for detecting the passenger compartment is installed inside the passenger compartment of the vehicle.

[0052] In the occupant detection method and occupant detection device according to this embodiment, the processor acquires second detection information from the detection sensor, which indicates that a second detection wave has been detected, and detects an occupant based on the second detection information. The second detection wave is a detection wave that has been transmitted from the detection sensor and reflected by an object without passing through a reflector. This allows for accurate detection of an occupant in the vehicle cabin when one sensor for detecting the interior of the vehicle is installed in the vehicle cabin.

[0053] In the occupant detection method and occupant detection device according to this embodiment, the vehicle interior is made up of a space in front of a first seat row that is located furthest forward of the seat rows in the vehicle interior, and a space behind the first seat row, and the detection sensor is located in an upper part of the space behind the vehicle, and the reflector is located in the space ahead of the vehicle. As a result, when the detection sensor is located in an upper part of the space behind the vehicle, it is possible to accurately detect an occupant in a blind spot caused by the seat row that is located furthest forward of the vehicle.

[0054] In the occupant detection method and occupant detection device according to this embodiment, the reflector is installed near the rearview mirror located at the top center of the front windshield of the vehicle, thereby allowing the detection wave emitted from the detection sensor to be reflected toward an occupant located in a blind spot caused by the seat row located at the frontmost position of the vehicle.

[0055] In the occupant detection method and occupant detection device according to this embodiment, the reflectors are installed on pillars located on the left and right sides of the vehicle's windshield, thereby allowing the detection wave emitted from the detection sensor to be reflected toward occupants in the blind spot caused by the seat row located nearest to the front of the vehicle.

[0056] In the occupant detection method and occupant detection device according to this embodiment, the reflector is installed on the ceiling of the space in the front of the vehicle, so that the detection wave emitted from the detection sensor can be reflected toward an occupant in a blind spot caused by the seat row located at the frontmost position of the vehicle.

[0057] In the occupant detection method and occupant detection device according to this embodiment, the seat rows in the vehicle cabin include three seat rows aligned along the front-to-rear direction of the vehicle, the detection sensor is located in an upper part of the space between a first seat row and a second seat row that is second from the front of the vehicle, and the reflectors are located in the space on the front side of the vehicle and in a space behind the second seat row. As a result, when the detection sensor is located in an upper part of the space between the first seat row and the second seat row, it can accurately detect occupants in a blind spot formed by the seat row that is closest to the front of the vehicle and occupants in a blind spot formed by the seat row that is second from the front of the vehicle.

[0058] In the occupant detection method and occupant detection device according to this embodiment, the vehicle further includes an exterior sensor for detecting an area outside the vehicle cabin, and the processor acquires detection information indicating the detection of a detection wave from the detection sensor and exterior detection information indicating the detection of an object outside the vehicle cabin from the exterior sensor, and determines whether the detection wave is a first detection wave or a detection wave reflected by the object outside the vehicle cabin based on the detection information and the exterior detection information. This prevents a detection wave transmitted from the detection sensor and reflected by an object outside the vehicle cabin from being mistakenly detected as a detection wave reflected by the object via a reflector.

[0059] In the occupant detection method and occupant detection device according to this embodiment, when the detection sensor is activated, the processor acquires detection information from the detection sensor indicating that the detection wave has been detected, determines whether the detection sensor is blocked by an obstruction based on the detection information, and if it determines that the detection sensor is blocked by an obstruction, outputs notification information indicating that the detection sensor is blocked by an obstruction via an output device inside the vehicle cabin. This prevents the detection sensor from being blocked and becoming unable to detect an occupant.

[0060] It should be noted that the above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0061] 2 Vehicle 10 Occupant detection device 100 Processor 101 Acquisition unit 102 Detection unit 103 Output unit 20 Detection sensor 30 Vehicle exterior sensor 40 In-vehicle communication device 50 Output device 60 Reflector

Claims

1. An occupant detection method executed by a processor for detecting an occupant in a passenger compartment of a vehicle, wherein the vehicle is equipped with a detection sensor inside the passenger compartment that emits a detection wave and detects the detection wave reflected off an object, and a reflector that reflects the detection wave, and the processor obtains first detection information from the detection sensor that detects a first detection wave, and detects the occupant based on the first detection information, wherein the first detection wave is the detection wave emitted from the detection sensor and reflected off the object via the reflector.

2. The processor acquires second detection information from the detection sensor detecting a second detection wave, and detects the occupant based on the second detection information, wherein the second detection wave is the detection wave transmitted from the detection sensor and reflected by the object without passing through the reflector. An occupant detection method as described in claim 1.

3. An occupant detection method as described in claim 1 or 2, wherein the interior of the vehicle compartment comprises a space forward of a first seat row that is located furthest forward of the seat rows in the vehicle compartment, and a space rearward of the first seat row, the detection sensor is located at an upper portion of the space rearward of the vehicle, and the reflector is located within the space forward of the vehicle.

4. The occupant detection method according to claim 3, wherein the reflector is disposed in the vicinity of a rearview mirror located at the upper center of the front window of the vehicle.

5. An occupant detection method as claimed in claim 3 or 4, wherein the reflectors are installed on pillars located on the left and right sides of the front windshield of the vehicle.

6. An occupant detection method as described in any one of claims 3 to 5, wherein the reflector is installed on a ceiling portion in the space in front of the vehicle.

7. An occupant detection method as described in any one of claims 3 to 6, wherein the seat rows in the vehicle cabin include three seat rows aligned along the fore-and-aft direction of the vehicle, the detection sensor is located at the upper part of the space between the first seat row and a second seat row that is second row from the front of the vehicle, and the reflector is located in the space on the front side of the vehicle and in the space on the rear side of the second seat row.

8. An occupant detection method as described in any one of claims 1 to 7, wherein the vehicle further comprises an outside-vehicle sensor for detecting the area outside the vehicle cabin, and the processor: acquires, from the detection sensor, detection information on the detection of the detection wave; acquires, from the outside-vehicle sensor, outside-vehicle detection information on the detection of an outside-vehicle object present outside the vehicle cabin; and, based on the detection information and the outside-vehicle detection information, determines whether the detection wave is the first detection wave or the detection wave reflected by the outside-vehicle object.

9. An occupant detection method as described in any one of claims 1 to 8, wherein the processor, when the detection sensor is activated, acquires detection information from the detection sensor that detects the detection wave, determines whether or not the detection sensor is blocked by an obstruction based on the detection information, and if it determines that the detection sensor is blocked by the obstruction, outputs notification information indicating that the detection sensor is blocked by the obstruction via an output device in the vehicle cabin.

10. An occupant detection device having a processor for detecting an occupant in a passenger compartment of a vehicle, wherein the vehicle is equipped with a detection sensor in the passenger compartment that emits a detection wave and detects the detection wave reflected by an object, and a reflector that reflects the detection wave, and the processor obtains first detection information from the detection sensor that detects a first detection wave, and detects the occupant based on the first detection information, wherein the first detection wave is the detection wave emitted from the detection sensor and reflected by the object via the reflector.

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