Object detection device, object detection method, and radar device

Abstract

To provide an object detection device that can detect the position of an object even in the situation where an obstacle exists between a sensor that transmits and receives electromagnetic waves and the object.SOLUTION: An object detection device 2 is configured to include a signal acquisition unit 11 that acquires received signals of respective scattered waves from a sensor 1 that emits a plurality of electromagnetic waves having mutually different emission directions and receives scattered waves of the respective electromagnetic waves, a distance calculation unit 12 that calculates the distance between a primary scattering point in each electromagnetic wave and a secondary scattering point in each electromagnetic wave based on the respective received signals acquired by the signal acquisition unit 11, and a position detection unit 13 that detects the position of an object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an object detection device, an object detection method, and a radar device. [Background technology]

[0002] 2. Description of the Related Art There is an object detection device that detects the position of an object based on a signal received by a sensor that emits electromagnetic waves and receives scattered waves of the electromagnetic waves. As an example of such an object detection device, Patent Document 1 discloses a device that detects the position of an object present around a vehicle. The device disclosed in Patent Document 1 includes a TOF (Time Of Flight) sensor that irradiates an object present around the vehicle with laser light, receives reflected light that is the laser light reflected by the object, and detects the position of the object based on the time from when the laser light is irradiated until the reflected light is received. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-90748 Summary of the Invention [Problem to be solved by the invention]

[0004] The device disclosed in Patent Document 1 had the problem that it could not detect the position of an object when an obstacle existed between the TOF sensor and the object, and the laser light from the TOF sensor to the object was blocked by the obstacle.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an object detection device that can detect the position of an object even when an obstacle exists between the object and a sensor that transmits and receives electromagnetic waves. [Means for solving the problem]

[0006] The object detection device according to the present disclosure includes a signal acquisition unit that acquires received signals of each scattered wave from a sensor that emits a plurality of electromagnetic waves having different radiation directions and receives scattered waves of each electromagnetic wave, a distance calculation unit that calculates the distance between a primary scattering point in each electromagnetic wave and a secondary scattering point in each electromagnetic wave from each received signal acquired by the signal acquisition unit, and a position detection unit that detects the position of an object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit. [Effects of the Invention]

[0007] According to the present disclosure, the position of an object can be detected even in a situation where an obstacle exists between the object and a sensor that transmits and receives electromagnetic waves. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a configuration diagram showing a radar device including an object detection device 2 according to a first embodiment. [Figure 2] 1 is a hardware configuration diagram showing hardware of an object detection device 2 according to the first embodiment. [Figure 3] FIG. 10 is a hardware configuration diagram of a computer when the object detection device 2 is realized by software, firmware, or the like. [Figure 4] 1 is an explanatory diagram showing the relationship between a sensor 1, an object to be detected, and an obstacle. [Figure 5] 5 is a bird's-eye view showing the XY plane as seen from the positive direction of the Z axis in FIG. 4. [Figure 6] 5 is a side view showing the XZ plane as viewed from the negative direction of the Y axis in FIG. 4. FIG. [Figure 7] 4 is a waveform diagram showing a signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a first direction. FIG. [Figure 8] 10 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a second direction. FIG. [Figure 9]FIG. 10 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a third direction. [Figure 10] FIG. 10 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a first direction when no object to be detected exists on the path of the electromagnetic wave radiated in the first direction. [Figure 11] 3 is a flowchart showing an object detection method, which is a processing procedure of the object detection device 2. [Figure 12] FIG. 10 is an explanatory diagram showing an example of first to sixth circles. [Figure 13] FIG. 10 is a configuration diagram showing a radar device including an object detection device 2 according to a second embodiment. [Figure 14] FIG. 10 is a hardware configuration diagram showing hardware of an object detection device 2 according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[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 FIG. 1 is a configuration diagram showing a radar device including an object detection device 2 according to the first embodiment. FIG. 2 is a hardware configuration diagram showing the hardware of the object detection device 2 according to the first embodiment. The radar device shown in FIG. 1 includes a sensor 1 and an object detection device 2. The radar device shown in FIG. 1 detects the position of an object when an obstacle exists between the sensor 1 and the object to be detected. 1 detects the position of an object present in the rear seat of a vehicle, or an object present between the front and rear seats of a vehicle. The object here is a concept that includes not only inanimate objects such as bags, but also living objects such as children or animals. In the radar device shown in FIG. 1, if the sensor 1 is installed on, for example, an instrument panel, the front seats and the like may become obstacles.

[0011] The radar device shown in FIG. 1 may be capable of detecting the position of an object when an obstacle exists between the sensor 1 and the object, and may also be capable of detecting an object that exists outside the vehicle. An example of a device that detects an object that exists outside the vehicle is a device that detects an object on a road where an obstacle exists between the sensor 1 and the object. Furthermore, for example, the sensor 1 may be configured to detect an object in a room where an obstacle exists between the sensor 1 and the object.

[0012] The sensor 1 is installed, for example, on an instrument panel inside the vehicle or on the ceiling inside the vehicle. The sensor 1 emits a plurality of electromagnetic waves with different radiation directions toward, for example, either a wall or a ceiling inside the vehicle. In this case, either the wall or the ceiling inside the vehicle becomes the primary scattering point. The sensor 1 emits a plurality of electromagnetic waves with different emission directions, and then receives scattered waves of each of the electromagnetic waves. The sensor 1 outputs the received signals of the respective scattered waves to the object detection device 2.

[0013] The object detection device 2 includes a signal acquisition unit 11, a distance calculation unit 12, and a position detection unit 13. The signal acquisition unit 11 is realized by, for example, a signal acquisition circuit 21 shown in FIG. The signal acquisition unit 11 acquires the received signals of the respective scattered waves from the sensor 1. The signal acquisition unit 11 outputs the received signals of the respective scattered waves to the distance calculation unit 12.

[0014] The distance calculation unit 12 is realized by, for example, a distance calculation circuit 22 shown in FIG. The distance calculation unit 12 acquires the received signals of the respective scattered waves from the signal acquisition unit 11. The distance calculation unit 12 calculates the distance between the primary scattering point of each electromagnetic wave and the secondary scattering point of each electromagnetic wave based on each received signal. Specifically, based on the signal waveform of each received signal, the distance calculation unit 12 determines the time difference between the time when the electromagnetic waves scattered at each primary scattering point are received by the sensor 1 and the time when the electromagnetic waves scattered at each secondary scattering point are received by the sensor 1. The distance calculation unit 12 calculates the distance between the primary scattering point and the secondary scattering point from the identified time difference. The distance calculation unit 12 outputs distance information indicating the distance between the primary scattering point and the secondary scattering point to the position detection unit 13.

[0015] The position detection unit 13 is realized by, for example, a position detection circuit 23 shown in FIG. The position detection unit 13 acquires the distance information from the distance calculation unit 12 . The position detection unit 13 calculates the position of the object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit 12.

[0016] 1, it is assumed that each of the components of the object detection device 2, that is, the signal acquisition unit 11, the distance calculation unit 12, and the position detection unit 13, is realized by dedicated hardware as shown in Fig. 2. In other words, it is assumed that the object detection device 2 is realized by a signal acquisition circuit 21, a distance calculation circuit 22, and a position detection circuit 23. Each of the signal acquisition circuit 21, the distance calculation circuit 22, and the position detection circuit 23 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.

[0017] The components of the object detection device 2 are not limited to those realized by dedicated hardware, and the object detection device 2 may 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. A computer refers to hardware that executes the program, such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor).

[0018] FIG. 3 is a hardware configuration diagram of a computer when the object detection device 2 is realized by software, firmware, or the like. When the object detection device 2 is realized by software, firmware, or the like, a program for causing a computer to execute the respective processing procedures of the signal acquisition unit 11, the distance calculation unit 12, and the position detection unit 13 is stored in the memory 31. Then, a processor 32 of the computer executes the program stored in the memory 31.

[0019] 2 shows an example in which each of the components of the object detection device 2 is realized by dedicated hardware, while Fig. 3 shows an example in which the object detection device 2 is realized by software, firmware, etc. However, this is merely an example, and some of the components in the object detection device 2 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, etc.

[0020] Next, the operation of the radar device shown in FIG. 1 will be described. FIG. 4 is an explanatory diagram showing the relationship between the sensor 1, the object to be detected, and the obstacle. FIG. 5 is a bird's-eye view showing the XY plane as viewed from the positive direction of the Z axis in FIG. FIG. 6 is a side view showing the XZ plane as viewed from the negative direction of the Y axis in FIG. In the examples of FIGS. 4 to 6, an obstacle exists between the sensor 1 and the object, so the object to be detected is located in a blind spot from the sensor 1. In the example of Figure 4, electromagnetic waves radiated from sensor 1 in a first direction, electromagnetic waves radiated from sensor 1 in a second direction, and electromagnetic waves radiated from sensor 1 in a third direction are shown.

[0021] The sensor 1 emits a plurality of electromagnetic waves with different radiation directions toward, for example, either a wall or a ceiling inside the vehicle. In this case, either the wall or the ceiling inside the vehicle becomes the primary scattering point. In the example of FIG. 4, the sensor 1 emits three electromagnetic waves toward the walls inside the vehicle. In the example of FIG. 4, the electromagnetic waves in the first direction, the electromagnetic waves in the second direction, and the electromagnetic waves in the third direction are each scattered by the wall inside the vehicle, and therefore the wall inside the vehicle is the primary scattering point SW 1A ,SW 2A ,SW 3A is.

[0022] Primary scattering point SW 1A Among the scattered waves, which are electromagnetic waves scattered at the primary scattering point SW, the scattered waves scattered in the direction of the sensor 1 return to the sensor 1. 1A Among the scattered waves scattered at the target object, the scattered waves scattered in the direction of the target object are scattered at the secondary scattering point SW 1B The scattered wave from the object to be detected is scattered at the primary scattering point SW 1A After being further scattered by the Primary scattering point SW 2A Among the scattered waves, which are electromagnetic waves scattered at the primary scattering point SW, the scattered waves scattered in the direction of the sensor 1 return to the sensor 1. 2A Among the scattered waves scattered at the target object, the scattered waves scattered in the direction of the target object are scattered at the secondary scattering point SW 2B The scattered wave from the object to be detected is scattered at the primary scattering point SW2A After being further scattered by the Primary scattering point SW 3A Among the scattered waves, which are electromagnetic waves scattered at the primary scattering point SW, the scattered waves scattered in the direction of the sensor 1 return to the sensor 1. 3A Among the scattered waves scattered at the target object, the scattered waves scattered in the direction of the target object are scattered at the secondary scattering point SW 3B The scattered wave from the object to be detected is scattered at the primary scattering point SW 3A After being further scattered by the Primary scattering point SW 1A The position of the first scattering point is (X1, Y1, Z1), and the 2A The position of the first scattering point SW 3A The position of the secondary scattering point SW is (X3, Y3, Z3). 1B, SW 2B, SW 2B The position is (x,y,z). In radar equipment, the primary scattering point SW 1A Position (X1, Y1, Z1), primary scattering point SW 2A Position (X2, Y2, Z2) and primary scattering point SW 3A Each of the positions (X3, Y3, Z3) is known.

[0023] FIG. 7 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a first direction. In the example of Figure 7, the electromagnetic wave emitted from sensor 1 is scattered at the primary scattering point SW 1A The light is scattered at the primary scattering point SW 1A Among the scattered waves, which are electromagnetic waves scattered in the direction of sensor 1, the scattered waves return to sensor 1. 1A is the first scattering point SW 1A This is the time when the scattered wave scattered in the direction of sensor 1 is received by sensor 1. Primary scattering point SW 1A Among the scattered waves scattered at the target object, the scattered waves scattered in the direction of the target object are scattered at the secondary scattering point SW 1BThe scattered wave from the object to be detected is scattered at the primary scattering point SW 1A After being further scattered by , it returns to sensor 1. At time t 1B is the secondary scattering point SW 1B From the first scattering point SW 1A This is the time when the sensor 1 receives the scattered wave that has returned to the sensor 1 via the

[0024] FIG. 10 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a first direction when there is no object to be detected on the path of the electromagnetic wave radiated in the first direction. When there is no object to be detected, the electromagnetic waves emitted from the sensor 1 are scattered, for example, by the backrest of the rear seat of the vehicle. The backrest is located farther from the sensor 1 than the object to be detected. Therefore, as shown in FIG. 10, at time t 1C is the reception time t 1B It will be later than By comparing the signal waveform shown in Figure 7 with the signal waveform shown in Figure 10, it is possible to determine whether or not a detection target object is present on the path of the electromagnetic wave emitted in the first direction.

[0025] FIG. 8 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a second direction. In the example of Figure 8, the electromagnetic wave emitted from sensor 1 is scattered at the primary scattering point SW 2A The light is scattered at the primary scattering point SW 2A Among the scattered waves, which are electromagnetic waves scattered in the direction of sensor 1, the scattered waves return to sensor 1. 2A is the first scattering point SW 2A This is the time when the scattered wave scattered in the direction of sensor 1 is received by sensor 1. Primary scattering point SW 2A Among the scattered waves scattered at the target object, the scattered waves scattered in the direction of the target object are scattered at the secondary scattering point SW 2B The scattered wave from the object to be detected is scattered at the primary scattering point SW2A After being further scattered by , it returns to sensor 1. At time t 2B is the secondary scattering point SW 2B From the first scattering point SW 2A This is the time when the sensor 1 receives the scattered wave that has returned to the sensor 1 via the

[0026] FIG. 9 is a waveform diagram showing the signal waveform of a received signal of a scattered wave related to an electromagnetic wave radiated in a third direction. In the example of Figure 9, the electromagnetic wave emitted from sensor 1 is scattered at the primary scattering point SW 3A The light is scattered at the primary scattering point SW 3A Among the scattered waves, which are electromagnetic waves scattered in the direction of sensor 1, the scattered waves return to sensor 1. 3A is the first scattering point SW 3A This is the time when the scattered wave scattered in the direction of sensor 1 is received by sensor 1. Primary scattering point SW 3A Among the scattered waves scattered at the target object, the scattered waves scattered in the direction of the target object are scattered at the secondary scattering point SW 3B The scattered wave from the object to be detected is scattered at the primary scattering point SW 3A After being further scattered by , it returns to sensor 1. At time t 3B is the secondary scattering point SW 3B From the first scattering point SW 3A This is the time when the sensor 1 receives the scattered wave that has returned to the sensor 1 via the

[0027] The sensor 1 emits multiple electromagnetic waves and then receives scattered waves of each electromagnetic wave. The electromagnetic waves emitted from the sensor 1 are, for example, pulsed light. However, the electromagnetic waves emitted from the sensor 1 are not limited to pulsed light as long as they are directional. The electromagnetic waves emitted from the sensor 1 may be modulated by a modulation method other than pulse modulation, such as frequency modulation. Furthermore, sound waves may be used instead of the electromagnetic waves emitted from the sensor 1. In this case, the sensor 1 emits multiple sound waves with different emission directions instead of multiple electromagnetic waves and receives scattered waves of each sound wave. The signal acquisition unit 11 acquires received signals of each scattered wave from the sensor 1. The distance calculation unit 12 calculates the distance between the primary scattering point of each sound wave and the secondary scattering point of each sound wave based on the received signals acquired by the signal acquisition unit 11. The position detection unit 13 detects the position of an object present at the secondary scattering point based on the position of the primary scattering point of each sound wave and the distance calculated by the distance calculation unit 12. The sensor 1 outputs the received signals of the respective scattered waves to the object detection device 2. For the sake of convenience, it is assumed below that the sensor 1 emits electromagnetic waves in a first direction, a second direction, and a third direction as shown in FIG. 4, and a primary scattering point SW 1A ,SW 2A ,SW 3A Scattered waves at the secondary scattering point SW 1B, SW 2B, SW 3B The scattered waves at and are received.

[0028] FIG. 11 is a flowchart showing an object detection method, which is a processing procedure of the object detection device 2. The signal acquisition unit 11 receives the primary scattering point SW 1A Signal of scattered wave at secondary scattering point SW 1B A received signal S including a signal of a scattered wave at the target and a signal of a scattered wave at the target is obtained (step ST1 in FIG. 11). The signal acquisition unit 11 also receives the primary scattering point SW 2A Signal of scattered wave at secondary scattering point SW 2BA received signal S including a signal of a scattered wave at the target and a signal of a scattered wave at the target is obtained (step ST1 in FIG. 11). The signal acquisition unit 11 also receives the primary scattering point SW 3A Signal of scattered wave at secondary scattering point SW 3B A received signal S including a signal of a scattered wave at the target and a signal of a scattered wave at the target is obtained (step ST1 in FIG. 11). The signal acquisition unit 11 outputs each of the received signals S to the distance calculation unit 12.

[0029] The distance calculation unit 12 acquires each of the received signals S from the signal acquisition unit 11 . The distance calculation unit 12 compares the signal level of each received signal S with a threshold value Th. The threshold value Th may be stored in an internal memory of the distance calculation unit 12, or may be provided from outside the object detection device 2. The distance calculation unit 12 calculates the first signal level that exceeds the threshold value Th after the electromagnetic wave is emitted from the sensor 1 at the primary scattering point SW. 1A ,SW 2A ,SW 3A It is determined that this is related to scattered waves at Furthermore, the distance calculation unit 12 determines that the second signal level that exceeds the threshold value Th after the electromagnetic wave is emitted from the sensor 1 is the secondary scattering point SW 1B, SW 2B, SW 3B It is determined that this is related to scattered waves at

[0030] Next, the distance calculation unit 12 calculates the primary scattering point SW 1A The scattered wave at time t is received by sensor 1. 1A and the secondary scattering point SW 1B The scattered wave at time t is received by sensor 1. 1B Identify the following. The distance calculation unit 12 calculates the distance at time t 1A and time t 1B Calculate the time difference Δt1. Δt1=t 1B -t 1A (1) The distance calculation unit 12 calculates the distance to the first scattering point SW based on the speed of light c of the scattered light and the time difference Δt1, as shown in the following equation (2): 1A and the secondary scattering point SW 1B The distance R1 between the two points is calculated (step ST2 in FIG. 11). R1=(c×Δt1) / 2 (2)

[0031] The distance calculation unit 12 calculates the primary scattering point SW 2A The scattered wave at time t is received by sensor 1. 2A and the secondary scattering point SW 2B The scattered wave at time t is received by sensor 1. 2B Identify the following. The distance calculation unit 12 calculates the distance at time t 2A and time t 2B The time difference Δt2 is calculated. Δt2=t 2B -t 2A (3) The distance calculation unit 12 calculates the distance between the first scattering point SW based on the speed of light c of the scattered light and the time difference Δt2 as shown in the following equation (4): 2A and the secondary scattering point SW 2B A distance R2 between the two points is calculated (step ST2 in FIG. 11). R2=(c×Δt2) / 2 (4)

[0032] The distance calculation unit 12 calculates the primary scattering point SW 3A The scattered wave at time t is received by sensor 1. 3A and the secondary scattering point SW 3B The scattered wave at time t is received by sensor 1. 3B Identify the following. The distance calculation unit 12 calculates the distance at time t 3A and time t 3B The time difference Δt3 is calculated. Δt3=t 3B -t 3A (5) The distance calculation unit 12 calculates the distance between the first scattering point SW based on the speed of light c of the scattered light and the time difference Δt3, as shown in the following equation (6): 3A and the secondary scattering point SW 3BA distance R3 between the two points is calculated (step ST2 in FIG. 11). R3=(c×Δt3) / 2 (6) The distance calculation unit 12 outputs distance information L indicating the distances R1, R2, and R3 to the position detection unit 13.

[0033] The position detection unit 13 acquires the distance information L from the distance calculation unit 12. The position detection unit 13 detects the primary scattering point SW 1A Position (X1, Y1, Z1), primary scattering point SW 2A Position (X2, Y2, Z2) and primary scattering point SW 3A The position (X3, Y3, Z3) and the secondary scattering point SW 1B ,SW 2B ,SW 3B Based on the position (x, y, z) of the object to be detected and the distances R1, R2, and R3 indicated by the distance information, the secondary scattering point SW 1B ,SW 2B ,SW 3B The position (x, y, z) of the secondary scattering point SW is calculated (step ST3 in FIG. 11). 1B and the position of the secondary scattering point SW 2B and the position of the secondary scattering point SW 3B The position of is the same position (x, y, z). Specifically, the distance calculation unit 12 calculates the secondary scattering point SW as the position of the object to be detected by solving the simultaneous equations shown in the following expressions (7) to (9). 1B, SW 2B, SW 3B Calculate the position (x,y,z) of

[0034] (x-X1) 2 +(y-Y1) 2 +(z-Z1) 2 =R1 2 (7) (x-X2) 2 +(y-Y2) 2 +(z-Z2) 2 =R2 2 (8) (x-X3) 2 +(y-Y3) 2 +(z-Z3) 2 =R32 (9)

[0035] The position detection unit 13 outputs information indicating the position (x, y, z) of the object to be detected to, for example, a driver monitoring device (not shown). When the driver monitoring receives information indicating the position (x, y, z) of the object to be detected from the position detection unit 13, it issues an alarm or the like indicating that an object is present in the rear seat or between the front and rear seats, for example, when the engine is stopped or the vehicle door is opened.

[0036] 4 shows an example in which there is one object to be detected, but this is merely an example, and there may be two or more objects to be detected. For example, if there are two objects to be detected, one of the two objects and the primary scattering point SW 1A The distance between the other object and the first scattering point SW 1A Unless the distances between the two points are perfectly matched, a certain received signal S will have a secondary scattering point SW 1B The scattered wave signal at the secondary scattering point SW 1B The other received signal S includes the signal of the scattered wave at the secondary scattering point SW 2B The scattered wave signal at the secondary scattering point SW 2B ' and the signal of the scattered wave at the secondary scattering point SW. 3B The scattered wave signal at the secondary scattering point SW 3B ' and the scattered wave signal at For convenience of explanation, we will assume that one object and the primary scattering point SW 1A The distance between the other object and the primary scattering point SW is R1. 1A Let the distance between be R1' and R1>R1'. Also, one object and the primary scattering point SW 1B The distance between the other object and the primary scattering point SW is R2. 1B Let the distance between be R2' and R2 > R2'. Furthermore, one object and the primary scattering point SW 1CThe distance between the other object and the primary scattering point SW is R3. 1C Let the distance between be R3' and R3>R3'.

[0037] In such a case, the position detection unit 13 detects that the center position is the primary scattering point SW 1A A first circle is placed, the radius of which is a distance R1, and the center position is the primary scattering point SW 1A and place a second circle whose radius is the distance R1'. 12, the position detection unit 13 detects the scattering point SW 2A A third circle is placed, the radius of which is a distance R2, and the center position is the primary scattering point SW 2A and place a fourth circle whose radius is the distance R2'. Furthermore, as shown in FIG. 12, the position detection unit 13 detects the center position of the primary scattering point SW 3A A fifth circle is placed, the radius of which is a distance R3, and the center position is the primary scattering point SW 3A and place a sixth circle whose radius is a distance R3'.

[0038] FIG. 12 is an explanatory diagram showing an example of the first to sixth circles. Of the first to sixth circles, any three circles intersect at a certain point, and the remaining three circles intersect at a point different from the certain point. In the example of FIG. 12, the first circle, the third circle, and the fifth circle intersect at a certain point, and the certain point is the secondary scattering point SW 1B, SW 2B, SW 3B is. In the example of FIG. 12, the second circle, the fourth circle, and the sixth circle intersect at a point different from the certain point, and the point different from the certain point is the secondary scattering point SW 1B ' , SW 2B ' , SW 3B ' is.

[0039] In the example of Figure 12, the position detection unit 13 calculates the position (x, y, z) of an object located at a certain point by solving simultaneous equations consisting of equation (7) where the distance is R1, equation (8) where the distance is R2, and equation (9) where the distance is R3, so as to satisfy the condition that they intersect at a certain point. In addition, the position detection unit 13 calculates the position (x, y, z) of an object located at a point different from the given point by solving simultaneous equations: Equation (7) where the distance is R1' (R1' is used instead of R1 in Equation (7)), Equation (8) where the distance is R2' (R2' is used instead of R2 in Equation (8)), and Equation (9) where the distance is R3' (R3' is used instead of R3 in Equation (9)), so as to satisfy the condition that the object intersects with the given point at a different point.

[0040] In the above-described first embodiment, the object detection device 2 is configured to include a signal acquisition unit 11 that acquires received signals of each scattered wave from the sensor 1 that emits a plurality of electromagnetic waves having different emission directions and receives scattered waves of each electromagnetic wave, a distance calculation unit 12 that calculates the distance between a primary scattering point in each electromagnetic wave and a secondary scattering point in each electromagnetic wave based on each received signal acquired by the signal acquisition unit 11, and a position detection unit 13 that detects the position of an object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit 12. Therefore, the object detection device 2 can detect the position of an object even in a situation where an obstacle is present between the object and the sensor 1 that transmits and receives the electromagnetic waves.

[0041] Embodiment 2 In embodiment 2, an object detection device 2 is described in which the position detection unit 14 compares the signal waveforms of the received signals of the scattered waves related to each electromagnetic wave when there is no object to be detected on the path of each electromagnetic wave with the signal waveforms of each received signal acquired by the signal acquisition unit 11, and determines whether or not an object is present on the path of each electromagnetic wave based on the comparison result of the signal waveforms.

[0042] Fig. 13 is a configuration diagram showing a radar device including an object detection device 2 according to embodiment 2. In Fig. 13, the same reference numerals as in Fig. 1 indicate the same or corresponding parts, and detailed description thereof will be omitted. Fig. 14 is a hardware configuration diagram showing the hardware of an object detection device 2 according to embodiment 2. In Fig. 14, the same reference numerals as in Fig. 2 indicate the same or corresponding parts, and detailed description thereof will be omitted.

[0043] The position detection unit 14 is realized by, for example, a position detection circuit 24 shown in FIG. The position detection unit 14 compares the signal waveform of the received signal of the scattered wave related to each electromagnetic wave when there is no object to be detected on the path of each electromagnetic wave with the signal waveform of each received signal acquired by the signal acquisition unit 11, and determines whether or not an object is present on the path of each electromagnetic wave based on the comparison result of the signal waveforms. If the position detection unit 14 determines that an object exists on the path of each electromagnetic wave, it calculates the position of the object existing at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit 12, similar to the position detection unit 13 shown in Figure 1.

[0044] 13, it is assumed that the signal acquisition unit 11, the distance calculation unit 12, and the position detection unit 14, which are components of the object detection device 2, are each realized by dedicated hardware as shown in Fig. 14. In other words, it is assumed that the object detection device 2 is realized by a signal acquisition circuit 21, a distance calculation circuit 22, and a position detection circuit 24. Each of the signal acquisition circuit 21, the distance calculation circuit 22, and the position detection circuit 24 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

[0045] The components of the object detection device 2 are not limited to those realized by dedicated hardware, and the object detection device 2 may be realized by software, firmware, or a combination of software and firmware. When the object detection device 2 is realized by software, firmware, or the like, a program for causing a computer to execute the respective processing procedures of the signal acquisition unit 11, the distance calculation unit 12, and the position detection unit 14 is stored in a memory 31 shown in Fig. 3. Then, a processor 32 shown in Fig. 3 executes the program stored in the memory 31.

[0046] 14 shows an example in which each of the components of the object detection device 2 is realized by dedicated hardware, while Fig. 3 shows an example in which the object detection device 2 is realized by software, firmware, etc. However, this is merely an example, and some of the components in the object detection device 2 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, etc.

[0047] Next, the operation of the radar device shown in Fig. 13 will be described. However, apart from the position detection unit 14, the radar device is the same as that shown in Fig. 1. Therefore, only the operation of the position detection unit 14 will be described here.

[0048] The position detection unit 14 acquires each received signal S from the signal acquisition unit 11 via the distance calculation unit 12. In the example of FIG. 13, the position detection unit 14 acquires each received signal S from the signal acquisition unit 11 via the distance calculation unit 12. However, this is merely an example, and the position detection unit 14 may also acquire each received signal S directly from the signal acquisition unit 11. The internal memory of the position detection unit 14 stores signal waveforms of the received signals S of the scattered waves associated with each electromagnetic wave when no object to be detected exists on the path of each electromagnetic wave. If the radiation direction of the electromagnetic wave is, for example, a first direction, a signal waveform such as that shown in FIG. 10 is stored. Here, it is assumed that the signal waveform of the received signal is stored in the internal memory of the position detection unit 14. However, this is merely an example, and the signal waveform of the received signal may be provided from outside the object detection device 2.

[0049] The position detection unit 14 compares the signal waveform of the received signal of the scattered wave related to each electromagnetic wave when there is no object to be detected on the path of each electromagnetic wave with the signal waveform of each received signal S acquired by the signal acquisition unit 11. If the radiation direction of the electromagnetic wave is, for example, the first direction, the position detection unit 14 compares, for example, the signal waveform shown in FIG. 7 with the signal waveform shown in FIG. If the radiation direction of the electromagnetic wave is the first direction, the position detection unit 14 detects in the received signal S, for example, a time t 1C time t earlier than 1B If there is a signal level greater than the threshold value Th, it is determined that an object exists on the path of the electromagnetic wave whose radiation direction is the first direction. The position detection unit 14 detects a time t 1C time t earlier than 1B If there is no signal level greater than the threshold value Th, it is determined that no object exists on the path of the electromagnetic wave whose radiation direction is the first direction.

[0050] If the radiation direction of the electromagnetic wave is the second direction, the position detection unit 14 detects in the received signal S, for example, a time t 2C time t earlier than 2B If there is a signal level greater than the threshold value Th, it is determined that an object exists on the path of the electromagnetic wave whose radiation direction is the second direction. The position detection unit 14 detects a time t 2C time t earlier than 2B If there is no signal level greater than the threshold value Th, it is determined that no object exists on the path of the electromagnetic wave whose radiation direction is the second direction.

[0051] If the radiation direction of the electromagnetic wave is the third direction, the position detection unit 14 detects in the received signal S, for example, a time t 3C time t earlier than 3B If there is a signal level greater than the threshold value Th, it is determined that an object exists on the path of the electromagnetic wave whose radiation direction is the third direction. The position detection unit 14 detects a time t 3C time t earlier than 3B If there is no signal level greater than the threshold value Th, it is determined that no object exists on the path of the electromagnetic wave whose radiation direction is the third direction.

[0052] If the position detection unit 14 determines that an object exists on the path of each electromagnetic wave, it calculates the position of the object existing at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit 12, similar to the position detection unit 13 shown in Figure 1.

[0053] In addition, the present disclosure allows for free combination of the respective embodiments, modification of any of the components of the respective embodiments, or omission of any of the components of the respective embodiments. [Explanation of symbols]

[0054] 1 sensor, 2 object detection device, 11 signal acquisition unit, 12 distance calculation unit, 13, 14 position detection unit, 21 signal acquisition circuit, 22 distance calculation circuit, 23, 24 position detection circuit, 31 memory, 32 processor

Claims

1. a signal acquisition unit that acquires received signals of the scattered waves from a sensor that emits a plurality of electromagnetic waves having different emission directions and receives scattered waves of the respective electromagnetic waves; a distance calculation unit that calculates a distance between a primary scattering point in each electromagnetic wave and a secondary scattering point in each electromagnetic wave based on each received signal acquired by the signal acquisition unit; a position detection unit that detects the position of an object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit; An object detection device comprising:

2. The distance calculation unit 2. The object detection device according to claim 1, wherein the time difference between the time at which the electromagnetic waves scattered at each primary scattering point are received by the sensor and the time at which the electromagnetic waves scattered at each secondary scattering point are received by the sensor is determined based on the signal waveform of each received signal, and the distance between the primary scattering point and the secondary scattering point is calculated from the time difference.

3. The position detection unit comparing the signal waveforms of the received signals of the scattered waves related to each electromagnetic wave when there is no object to be detected on the path of each electromagnetic wave with the signal waveforms of the received signals acquired by the signal acquisition unit, and determining whether or not an object is present on the path of each electromagnetic wave based on the comparison results of the signal waveforms; 2. The object detection device according to claim 1, wherein, if it is determined that an object exists on the path of each electromagnetic wave, the position of the object existing at the secondary scattering point is detected based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit.

4. The signal acquisition unit Instead of the plurality of electromagnetic waves, a plurality of sound waves having different radiation directions are emitted, and a sensor receives scattered waves of the respective sound waves, and acquires received signals of the respective scattered waves; The distance calculation unit calculating a distance between a primary scattering point in each sound wave and a secondary scattering point in each sound wave based on each received signal acquired by the signal acquisition unit; The position detection unit The position of an object present at the secondary scattering point is detected based on the position of the primary scattering point in each sound wave and the distance calculated by the distance calculation unit.

2. The object detection device according to claim 1.

5. a signal acquiring unit acquiring received signals of the scattered waves from a sensor that emits a plurality of electromagnetic waves having different emission directions and receives scattered waves of the respective electromagnetic waves; a distance calculation unit that calculates a distance between a primary scattering point in each electromagnetic wave and a secondary scattering point in each electromagnetic wave based on each received signal acquired by the signal acquisition unit; A position detection unit detects the position of an object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit. Object detection methods.

6. a sensor that emits a plurality of electromagnetic waves having different emission directions and receives scattered waves of the respective electromagnetic waves; a signal acquisition unit that acquires a received signal of each scattered wave from the sensor; a distance calculation unit that calculates a distance between a primary scattering point in each electromagnetic wave and a secondary scattering point in each electromagnetic wave based on each received signal acquired by the signal acquisition unit; a position detection unit that detects the position of an object present at the secondary scattering point based on the position of the primary scattering point in each electromagnetic wave and the distance calculated by the distance calculation unit; A radar device comprising:

7. The sensor It is installed in the vehicle, radiating each electromagnetic wave toward either a wall inside the vehicle or a ceiling inside the vehicle; 7. The radar device according to claim 6, wherein the primary scattering point is either a wall inside the vehicle or a ceiling inside the vehicle.

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