Object detection device and object detection program

Abstract

To provide an object detector and an object detection program which can detect the angle of an object.SOLUTION: An object detector 40 that executes an object detection program calculates a relative angle at which the frequency of relative angles of reflection points of an object to a vehicle is largest up to the present time since the object has been detected, calculates a first evaluation angle at which the absolute value of a difference with the relative angle at which the frequency is largest up to the present time since the object has been detected and a second evaluation angle smaller than the first evaluation angle, determines that a reflection point when the frequency of the relative angle becoming greater than or equal to the first evaluation angle is greater than or equal to a first threshold is the angle of the object, and determines that a reflection point when the frequency of the relative angle becoming lower than or equal to a second evaluation angle is greater than or equal to a second threshold is the angle of the object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an object detection device and an object detection program. [Background technology]

[0002] Conventionally, as described in Patent Document 1, there is known a vehicle control device that recognizes the presence or absence of an object around the vehicle based on the situation around the vehicle obtained by a detection sensor and recognizes an area where the presence or absence of an object cannot be recognized as an unspecified area. This vehicle control device treats the unspecified area as if an object exists. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-008224 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the inventors' research, the vehicle control device described in Patent Document 1 merely recognizes the presence or absence of objects by treating unspecified areas as if they contain objects, and is unable to detect corners of objects such as vehicles and walls.

[0005] The present disclosure aims to provide an object detection device and an object detection program capable of detecting corners of an object. [Means for solving the problem]

[0006] The invention described in claim 1 is an object detection device used in a vehicle equipped with a distance measuring sensor (26) that detects an object by transmitting a search wave to the side of the vehicle (10) and receiving the search wave reflected by an object (80), and the object detection device includes a frequency calculation unit (S206) that calculates a relative angle (θcr) of a reflection point of the object with respect to the vehicle that occurs most frequently from when the object is detected to a current time, an evaluation calculation unit (S208) that calculates a first evaluation angle (θe1) whose absolute value of the difference between this and the relative angle that occurs most frequently from when the object is detected to the current time is a predetermined angle Δθ, and a second evaluation angle (θe2) that is smaller than the first evaluation angle, and a determination unit (S212, S214) that determines that a reflection point is a corner of the object when the frequency when the relative angle is equal to or greater than the first evaluation angle is equal to or greater than a first threshold, and determines that a reflection point is a corner of the object when the frequency when the relative angle is equal to or less than the second evaluation angle is equal to or greater than a second threshold.

[0007] The invention described in claim 2 is an object detection program that causes an object detection device used in a vehicle having a distance measuring sensor (26) that detects an object by transmitting a search wave to the side of the vehicle (10) and receiving the search wave reflected by the object (80) to function as a frequency calculation unit (S206) that calculates the most frequent relative angle (θcr) of the reflection point of the object with respect to the vehicle from when the object was detected to the current time, an evaluation calculation unit (S208) that calculates a first evaluation angle (θe1) whose absolute value of the difference from the most frequent relative angle from when the object was detected to the current time is a predetermined angle Δθ and a second evaluation angle (θe2) that is smaller than the first evaluation angle, and a determination unit (S212, S214) that determines that a reflection point is a corner of the object when the frequency when the relative angle is equal to or greater than the first evaluation angle is equal to or greater than a first threshold, and determines that a reflection point is a corner of the object when the frequency when the relative angle is equal to or less than the second evaluation angle is equal to or greater than a second threshold.

[0008] This makes it possible to detect the corners of an object.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a vehicle system in which an object detection device according to a first embodiment is used. [Diagram 2] FIG. 1 is a diagram showing a vehicle in which an object detection device is used. [Diagram 3] 4 is a flowchart showing a process of the object detection device. [Figure 4] 11 is a diagram showing the relationship between the amount of movement of the host vehicle and the amount of change when the vehicle moves forward. [Diagram 5] 11 is a diagram showing the relationship between the host vehicle movement amount and the change amount when the vehicle moves backward. FIG. [Figure 6] 11 is a diagram showing the relationship between the amount of movement of the host vehicle and the amount of change when the vehicle moves forward. [Figure 7] 11 is a diagram showing the relationship between the host vehicle movement amount and the change amount when the vehicle moves backward. FIG. [Figure 8] 11 is a diagram showing the relationship between the amount of movement of the host vehicle and the amount of change when the vehicle moves forward. [Figure 9] FIG. 13 is a diagram showing the relationship between the object angle and the change rate threshold. [Figure 10] 4 is a time chart showing the processing of the object detection device. [Figure 11] 10 is a flowchart showing a process of an object detection device according to a second embodiment. [Figure 12] FIG. 11 is a diagram showing an example of a histogram created by processing of the object detection device. [Figure 13] 11 is a diagram showing a change in detection angle when the vehicle moves forward. [Figure 14] 13 is a diagram showing a change in the detection angle when the vehicle moves backward. [Figure 15] 11 is a diagram showing a change in detection angle when the vehicle moves forward. [Figure 16] 13 is a diagram showing a change in the detection angle when the vehicle moves backward. [Figure 17]10 is a flowchart showing a process of an object detection device according to another embodiment. [Figure 18] 10 is a flowchart showing a process of an object detection device according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals, and the description thereof will be omitted.

[0012] (First embodiment) The object detection device 40 of this embodiment is used in a system 15 of a vehicle 10. First, the system 15 will be described.

[0013] As shown in FIGS. 1 and 2, the system 15 includes a gyro sensor 22, a vehicle speed sensor 24, a lateral distance measuring sensor 26, an object detection device 40, and a driving control device 50.

[0014] The gyro sensor 22 outputs a signal corresponding to the attitude of the vehicle 10 to the object detection device 40 described later. The vehicle speed sensor 24 outputs a signal corresponding to the vehicle speed Vc to the object detection device 40 described later. Note that the vehicle speed Vc here indicates the magnitude of the speed of the vehicle 10.

[0015] The lateral distance measuring sensors 26 are attached to the left front, right front, left rear, and right rear of the vehicle 10. The lateral distance measuring sensors 26 transmit exploration waves such as millimeter waves, sonar, and infrared rays toward the sides of the vehicle 10. At this time, if an object 80 is present on the side of the vehicle 10, the lateral distance measuring sensors 26 receive the exploration waves reflected by the object 80. Furthermore, the lateral distance measuring sensors 26 detect the relative position of the reflection point of the object 80 on the side of the vehicle 10 based on information obtained from the received exploration waves. The lateral distance measuring sensors 26 also output a signal corresponding to the detected relative position to the object detection device 40 described later. Note that, if the lateral distance measuring sensors 26 cannot receive the exploration waves reflected by the object 80, they output a signal indicating that the object 80 was not detected to the object detection device 40 described later.

[0016] The object detection device 40 is a microcomputer equipped with a CPU, RAM, ROM, flash memory, etc. The RAM, ROM, and flash memory are all non-transient substantial storage media. The CPU executes a program stored in the ROM or flash memory, and uses the RAM as a working area at that time. In addition, the object detection device 40 detects a corner of an object 80 on the side of the vehicle 10 based on signals from the gyro sensor 22, the vehicle speed sensor 24, and the lateral distance measuring sensor 26 by the execution of the program by the CPU of the object detection device 40. The detection of this corner will be described later.

[0017] The driving control device 50 is a microcomputer equipped with a CPU, RAM, ROM, flash memory, etc. The RAM, ROM, and flash memory are all non-transient substantial storage media. The CPU executes a program stored in the ROM or flash memory, and uses the RAM as a working area at that time. In addition, the driving control device 50 calculates the driving route of the vehicle 10 based on the position information of the corner detected by the object detection device 40 by the execution of the program by the CPU of the driving control device 50.

[0018] As described above, the system 15 of the vehicle 10 including the object detection device 40 is configured. The object detection device 40 detects the corner of the object 80 on the side of the vehicle 10. Next, detection by the object detection device 40 will be described with reference to the flowchart of FIG. 3 and FIGS. 4 to 9. The detection program is executed, for example, when the vehicle 10 starts automatically. In the following, the period of a series of operations from when the processing of step S100 of the object detection device 40 starts until the processing of step S100 is returned to is defined as the control period τ of the object detection device 40. A coordinate system fixed in the space outside the vehicle 10 is defined as an absolute coordinate system Σ. Furthermore, the X-axis, Y-axis, and Z-axis in the absolute coordinate system Σ are mutually orthogonal. Moreover, this absolute coordinate system Σ is expressed as a right-handed system. Furthermore, a coordinate system having a predetermined position in the vehicle 10 as the origin is defined as a vehicle coordinate system Σc. For example, the predetermined position in the vehicle 10 is the center of gravity of the vehicle 10. Also, the front of the vehicle 10 is defined as the positive direction of the Xc axis in the vehicle coordinate system Σc. Furthermore, the left side of the vehicle 10 is defined as the positive direction of the Yc axis in the vehicle coordinate system Σc. Furthermore, the upper side of the vehicle 10 is defined as the positive direction of the Zc axis in the vehicle coordinate system Σc. Therefore, here, the vehicle coordinate system Σc is represented as a right-handed system. Furthermore, in order to make the state easier to understand, here, the positive direction of the Xc axis in the vehicle coordinate system Σc coincides with the positive direction of the X axis in the absolute coordinate system Σ. Furthermore, the positive direction of the Yc axis in the vehicle coordinate system Σc coincides with the positive direction of the Y axis in the absolute coordinate system Σ. Furthermore, the positive direction of the Zc axis in the vehicle coordinate system Σc coincides with the positive direction of the Z axis in the absolute coordinate system Σ.

[0019] In step S100, the object detection device 40 acquires various information. Specifically, the object detection device 40 acquires the attitude of the vehicle 10 from the gyro sensor 22. Furthermore, the object detection device 40 acquires the vehicle speed Vc from the vehicle speed sensor 24. Furthermore, the object detection device 40 acquires from the side distance measurement sensor 26 whether or not the object 80 is detected. Furthermore, the object detection device 40 acquires from the side distance measurement sensor 26 the relative position of the reflection point of the object 80 on the side of the vehicle 10, that is, the position of the reflection point of the object 80 in the vehicle coordinate system Σc. Note that, if the object 80 is not detected on the side of the vehicle 10 by the side distance measurement sensor 26, the object detection device 40 acquires from the side distance measurement sensor 26 a signal indicating that the object 80 has not been detected.

[0020] Next, in step S102, the object detection device 40 determines whether or not the object 80 has been detected based on the signal obtained in step S100 from the lateral distance measuring sensor 26. If the object 80 has been detected, the process of the object detection device 40 proceeds to step S104. If the object 80 has not been detected, the process of the object detection device 40 returns to step S100.

[0021] Next, in step S104, the object detection device 40 multiplies the vehicle speed Vc acquired in step S100 by the control period τ, as shown in the following relational expression (1). In this way, the object detection device 40 calculates the host vehicle movement amount ΔLc.

[0022]

number

[0023] Next, in step S106, the object detection device 40 calculates the position of the vehicle 10 in the absolute coordinate system Σ by using the attitude of the vehicle 10 acquired in step S100 and the vehicle movement amount ΔLc calculated in step S104. The object detection device 40 also adds the position coordinate of the reflection point of the object 80 in the vehicle coordinate system Σc acquired in step S100 to the calculated position coordinate of the vehicle 10 in the absolute coordinate system Σ. In this way, the object detection device 40 calculates the position coordinate of the reflection point of the object 80 in the absolute coordinate system Σ. Furthermore, the object detection device 40 substitutes the calculated coordinate of the reflection point of the object 80 in the current control cycle and the coordinate of the reflection point of the object 80 in the previous control cycle into the following relational expression (2). In this way, the object detection device 40 calculates the change amount ΔLr of the reflection point of the object 80 in the absolute coordinate system Σ. In the following relational expression (2), ΔLr(n) is the change amount ΔLr in the current control cycle. xr(n) is the X coordinate of the reflection point of the object 80 in the current control cycle. xr(n-1) is the X coordinate of the reflection point of the object 80 in the previous control cycle. n is a natural number of 2 or more.

[0024]

number

[0025] Next, in step S108, the object detection device 40 divides the amount of change ΔLr calculated in step S106 by the amount of vehicle movement ΔLc calculated in step S104, as shown in the following relational expression (3). In this way, the object detection device 40 calculates the rate of change Rr.

[0026]

number

[0027] Here, it is assumed that the object 80 faces the positive direction of the X-axis and the Xc-axis. Furthermore, it is assumed that the vehicle 10 moves forward or backward, and the search wave from the side distance measuring sensor 26 is reflected at a part of the object 80 that is not a corner, for example, at the side of the object 80, before and after the movement of the vehicle 10. At this time, as shown in FIG. 4 and FIG. 5, since the side distance measuring sensor 26 moves together with the vehicle 10, the reflection point of the object 80 by the search wave from the side distance measuring sensor 26 also moves together with the vehicle 10. In addition, the line connecting the reflection points before and after the movement of the vehicle 10 becomes a straight line parallel to the X-axis and the Xc-axis. Therefore, at this time, the change amount ΔLr is equal to the host vehicle movement amount ΔLc, and the change rate Rr becomes 1. In addition, in the figure, the reflection point before the movement of the vehicle 10 is indicated by Pr_b. In addition, the reflection point after the movement of the vehicle 10 is indicated by Pr_a.

[0028] Assume also that the object 80 faces the positive direction of the X-axis and the Xc-axis. Assume further that the vehicle 10 moves forward or backward, so that the search wave from the side distance measuring sensor 26 is reflected by the side of the object 80 before the vehicle 10 moves, and the search wave from the side distance measuring sensor 26 is reflected by the corner of the object 80 before the vehicle 10 moves. At this time, as shown in FIG. 6 and FIG. 7, since the side distance measuring sensor 26 moves together with the vehicle 10, the reflection point of the object 80 by the search wave from the side distance measuring sensor 26 also moves together with the vehicle 10. Also, the line connecting the reflection points before and after the movement of the vehicle 10 changes from a straight line parallel to the X-axis and the Xc-axis to a straight line intersecting the X-axis and the Xc-axis. Therefore, at this time, the position change of the X-coordinate of the reflection point becomes small, so the change amount ΔLr becomes smaller than the vehicle movement amount ΔLc. Therefore, at this time, the change rate Rr becomes smaller than 1. Therefore, when the rate of change Rr is equal to or less than the rate of change threshold Rr_th, it is determined that the reflection point of the object 80 at this time is a corner of the object 80, and thus the corner of the object 80 can be detected.

[0029] Further, assume that an axis extending forward of the object 80 intersects with the X-axis and the Xc-axis directions. Assume also that the vehicle 10 moves forward or backward, causing the search wave from the lateral distance measuring sensor 26 to be reflected by the side of the object 80 before and after the movement of the vehicle 10. In this case, as shown in Fig. 8, as the object angle θo, which is the angle between the axis extending forward of the object 80 and the Xc-axis in the vehicle coordinate system Σc, increases, the amount of change ΔLr decreases. For this reason, it is necessary to change the change rate threshold Rr_th depending on the orientation of the object 80.

[0030] Therefore, in step S110 following step S108, the object detection device 40 calculates the object angle θo based on the position coordinates of the reflection point of the object 80 in the vehicle coordinate system Σc acquired in step S100.

[0031] Specifically, the object detection device 40 calculates an approximation line of the reflection point group of the object 80 by using the X-coordinate and Y-coordinate of the reflection point of the object 80 in the vehicle coordinate system Σc and the least squares method. The object detection device 40 also calculates the object angle θo by calculating the angle between the calculated approximation line and the Xc axis. Note that the object detection device 40 is not limited to calculating the object angle θo by using the least squares method. For example, the object detection device 40 may calculate a straight line between two points from the Xc coordinate and the Yc coordinate of the reflection point of the object 80 in the current control cycle and the previous control cycle, and calculate the angle between the calculated straight line and the Xc axis to calculate the object angle θo.

[0032] The object detection device 40 also calculates the change rate threshold Rr_th using the calculated object angle θo and the table. As described above, the amount of change ΔLr decreases as the object angle θo increases. Therefore, in this table, as shown in FIG 9, the change rate threshold Rr_th decreases as the object angle θo increases.

[0033] Next, in step S112, the object detection device 40 determines whether the rate of change Rr calculated in step S108 is equal to or less than the rate of change threshold Rr_th calculated in step S110. In this way, the object detection device 40 detects a corner of the object 80 by determining whether the reflection point of the object 80 is a corner of the object 80. Then, when the rate of change Rr is equal to or less than the rate of change threshold Rr_th, the process of the object detection device 40 proceeds to step S114. On the other hand, when the rate of change Rr is greater than the rate of change threshold Rr_th, the process of the object detection device 40 proceeds to step S116.

[0034] In step S114 following step S112, since the rate of change Rr is equal to or less than the rate of change threshold Rr_th, the object detection device 40 determines that the reflection point is a corner of the object 80. The object detection device 40 also outputs the position of the corner of the object 80 in the absolute coordinate system Σ to the driving control device 50. Furthermore, the driving control device 50 calculates a route based on the position information of the corner to calculate the shortest route that can avoid a collision between the vehicle 10 and the object 80. Furthermore, the driving control device 50 automatically moves the vehicle 10 along this calculated route. Thereafter, the processing of the object detection device 40 returns to step S100.

[0035] In step S116 following step S112, since the rate of change Rr is greater than the rate of change threshold Rr_th, the object detection device 40 determines that the reflection point is not a corner of the object 80. At this time, since the position of the corner of the object 80 is unknown, the driving control device 50 calculates, for example, a route for the vehicle 10 to move forward or backward. Furthermore, the driving control device 50 automatically moves the vehicle 10 along this calculated route. After that, the processing of the object detection device 40 returns to step S100.

[0036] As described above, the object detection device 40 detects the corner of the object 80 on the side of the vehicle 10. Next, the processing of the object detection device 40 in one example will be described with reference to the time chart of FIG. 10. In this example, the object 80 is, for example, another vehicle different from the vehicle 10. In addition, this other vehicle is stopped. Furthermore, in the initial state, the front of the vehicle 10 and the front of the other vehicle coincide with the positive direction of the X-axis in the absolute coordinate system Σ. In addition, since the vehicle 10 is automatically starting, the program of the object detection device 40 is started.

[0037] At the initial time t0, the vehicle 10 moves forward at a predetermined vehicle speed Vc. At this time, since another vehicle is detected to the side of the vehicle 10, the object detection device 40 calculates the host vehicle movement amount ΔLc in step S104. Furthermore, the object detection device 40 calculates the change amount ΔLr of the reflection point on the side of the other vehicle in step S106. Furthermore, the object detection device 40 calculates the change rate Rr using the calculated host vehicle movement amount ΔLc and change amount ΔLr in step S108. At this time, since the side distance measuring sensor 26 moves together with the vehicle 10, the reflection point of the object 80 by the exploration wave from the side distance measuring sensor 26 also moves together with the vehicle 10. Furthermore, the line connecting the reflection points before and after the movement of the vehicle 10 becomes a straight line parallel to the X-axis and the Xc-axis. Therefore, at this time, the change amount ΔLr is equal to the host vehicle movement amount ΔLc, and the change rate Rr becomes 1. Furthermore, since the front of the vehicle 10 and the front of the other vehicle coincide with the positive direction of the X-axis in the absolute coordinate system Σ, the object angle θo is 0 degrees. Therefore, in step S110, the object detection device 40 uses a table to calculate the change rate threshold Rr_th when the object angle θo is 0 degrees. However, since the change rate Rr is greater than the change rate threshold Rr_th, the object detection device 40 determines in step S116 that the reflection point is not a corner of the object 80. At this time, since the position of the corner of the object 80 is unknown, the driving control device 50 calculates a route for the vehicle 10 to move forward. Furthermore, the driving control device 50 automatically moves the vehicle 10 along this calculated route.

[0038] During the period from the initial time t0 to the time t1, the vehicle 10 moves forward at the same vehicle speed Vc as at the initial time t0. Since the vehicle speed Vc is the same as at the initial time t0, the vehicle movement amount ΔLc is the same as at the initial time t0. Since the side distance measuring sensor 26 moves together with the vehicle 10, the reflection point of the object 80 by the exploration wave from the side distance measuring sensor 26 also moves together with the vehicle 10. Furthermore, a line connecting the reflection points before and after the movement of the vehicle 10 becomes a straight line parallel to the X-axis and the Xc-axis. Therefore, at this time, the change amount ΔLr is equal to the vehicle movement amount ΔLc, and the change rate Rr is 1. Furthermore, since the front of the vehicle 10 and the front of the other vehicle coincide with the positive direction of the X-axis in the absolute coordinate system Σ, the object angle θo is 0 degrees. Therefore, in step S110, the object detection device 40 uses a table to calculate the change rate threshold value Rr_th when the object angle θo is 0 degrees. However, since the rate of change Rr is greater than the rate of change threshold Rr_th, the object detection device 40 determines in step S116 that the reflection point is not a corner of the object 80. At this time, since the position of the corner of the object 80 is unknown, the driving control device 50 calculates a route for the vehicle 10 to advance. Furthermore, the driving control device 50 automatically moves the vehicle 10 along this calculated route.

[0039] At time t1, the vehicle 10 moves forward at the same vehicle speed Vc as at the initial time t0. Since the vehicle speed Vc is the same as at the initial time t0, the vehicle movement amount ΔLc is the same as at the initial time t0. In addition, the lateral distance measuring sensor 26 moves forward together with the vehicle 10, and since the reflection point approaches the corner of the object 80, the line connecting the reflection points before and after the movement of the vehicle 10 changes from a straight line parallel to the X-axis and the Xc-axis to a straight line intersecting the X-axis and the Xc-axis. This reduces the position change of the X-coordinate of the reflection point. Therefore, the change amount ΔLr is reduced, and the change rate Rr is reduced. However, since the change rate Rr is greater than the change rate threshold Rr_th, the object detection device 40 determines in step S116 that the reflection point is not the corner of the object 80. At this time, since the position of the corner of the object 80 is unknown, the driving control device 50 calculates the path along which the vehicle 10 will move forward. Moreover, the driving control device 50 automatically moves the vehicle 10 along the calculated route.

[0040] During the period from time t1 to time t2, the vehicle 10 moves forward at the same vehicle speed Vc as at the initial time t0. Since the vehicle speed Vc is the same as at the initial time t0, the vehicle movement amount ΔLc is the same as at the initial time t0. In addition, the lateral distance measuring sensor 26 moves forward together with the vehicle 10, and since the reflection point approaches the corner of the object 80, the line connecting the reflection points before and after the movement of the vehicle 10 changes from a straight line parallel to the X-axis and the Xc-axis to a straight line intersecting the X-axis and the Xc-axis. This reduces the position change in the X-coordinate of the reflection point. Therefore, the change amount ΔLr is reduced, and the change rate Rr is reduced. However, since the change rate Rr is greater than the change rate threshold Rr_th, the object detection device 40 determines in step S116 that the reflection point is not the corner of the object 80. At this time, since the position of the corner of the object 80 is unknown, the driving control device 50 calculates the path along which the vehicle 10 will move forward. Moreover, the driving control device 50 automatically moves the vehicle 10 along the calculated route.

[0041] At time t2, the vehicle 10 moves forward at the same vehicle speed Vc as at the initial time t0. Since the vehicle speed Vc is the same as at the initial time t0, the vehicle movement amount ΔLc is the same as at the initial time t0. In addition, the side distance measuring sensor 26 moves forward together with the vehicle 10, and since the reflection point approaches the corner of the object 80, the line connecting the reflection points before and after the movement of the vehicle 10 changes from a straight line parallel to the X-axis and the Xc-axis to a straight line intersecting the X-axis and the Xc-axis. This reduces the position change of the X-coordinate of the reflection point. Therefore, the amount of change ΔLr is reduced, and the rate of change Rr is reduced. At this time, since the rate of change Rr is equal to or less than the rate of change threshold Rr_th, the object detection device 40 determines in step S114 that the reflection point is the corner of the object 80. In addition, the object detection device 40 outputs the position of the corner of the object 80 in the absolute coordinate system Σ to the driving control device 50. Furthermore, the driving control device 50 calculates a route based on the position information of the corner, thereby calculating the shortest route that can avoid a collision between the vehicle 10 and the object 80. The driving control device 50 also automatically moves the vehicle 10 along this calculated route. Thereafter, as the vehicle 10 moves, the object 80 becomes undetectable. At this time, the object detection device 40 repeats the process of step S100.

[0042] As described above, the object detection device 40 detects the corners of the object 80 on the sides of the vehicle 10. Next, the ability of the object detection device 40 to detect the corners of the object 80 on the sides of the vehicle 10 will be described.

[0043] In step S104, the object detection device 40 calculates the host vehicle movement amount ΔLc based on the vehicle speed Vc and the control period τ. In step S106, the object detection device 40 calculates the change amount ΔLr based on the position coordinates of the reflection point of the object 80 where the exploration wave transmitted from the side distance measuring sensor 26 is reflected. In step S112 and step S114, the object detection device 40 determines that the reflection point is a corner of the object 80 when the change amount ΔLr is smaller than the host vehicle movement amount ΔLc. This makes it possible to detect the corner of the object 80 on the side of the vehicle 10. The object detection device 40 corresponds to a movement calculation unit, a change calculation unit, a position change calculation unit, and a determination unit. The vehicle speed Vc corresponds to the speed of the vehicle 10. The control period τ corresponds to time. The host vehicle movement amount ΔLc corresponds to a value related to the movement amount of the vehicle 10. The amount of change ΔLr corresponds to a value related to the change in position of the reflection point in the moving direction of the vehicle 10 when the vehicle 10 moves.

[0044] Moreover, the first embodiment also provides the following effects.

[0045] [1-1] In step S108, the object detection device 40 calculates a change rate Rr, which is a value obtained by dividing the amount of change ΔLr by the amount of movement of the host vehicle ΔLc. Furthermore, when the change rate Rr is equal to or less than a change rate threshold Rr_th, the object detection device 40 determines that the reflection point is a corner of the object 80. This makes it easier to detect the corner of the object 80 on the side of the vehicle 10. The object detection device 40 corresponds to a change rate calculation unit. The change rate Rr corresponds to a value obtained by dividing a value related to the position change of the reflection point of the object 80 before and after the movement of the vehicle 10 by a value related to the amount of movement of the vehicle 10.

[0046] [1-2] In step S110, the object detection device 40 reduces the change rate threshold Rr_th as the object angle θo increases. This reduces the change rate threshold Rr_th even if the change rate Rr decreases as the object angle θo increases and the amount of change ΔLr decreases. This makes it possible to prevent the corners of the object 80 from being erroneously detected. The object detection device 40 corresponds to a threshold change unit.

[0047] Second embodiment In the second embodiment, the processing of the object detection device 40 is different. The rest is the same as in the first embodiment. The processing of the object detection device 40 will be described with reference to the flowchart of FIG. 11 and FIGS. 12-16. This detection program is executed, for example, when the vehicle 10 starts automatically. In addition, hereinafter, the period of a series of operations from when the processing of step S200 of the object detection device 40 is started to when the processing of step S200 is returned to is defined as the control period τ of the object detection device 40. Furthermore, the angle formed by the Xc axis in the vehicle coordinate system Σc and the straight line connecting the side distance measuring sensor 26 and the reflection point of the object 80 is defined as the detection angle θcr.

[0048] In step S200, the object detection device 40 acquires various information. Specifically, the object detection device 40 acquires the attitude of the vehicle 10 from the gyro sensor 22. Furthermore, the object detection device 40 acquires the vehicle speed Vc from the vehicle speed sensor 24. Furthermore, the object detection device 40 acquires from the side distance measurement sensor 26 whether or not the object 80 is detected. Furthermore, the object detection device 40 acquires the relative position of the reflection point of the object 80 on the side of the vehicle 10, that is, the position of the reflection point of the object 80 in the vehicle coordinate system Σc from the side distance measurement sensor 26, thereby acquiring the detection angle θcr. Furthermore, when the object 80 is not detected on the side of the vehicle 10 by the side distance measurement sensor 26, the object detection device 40 acquires a signal indicating that the object 80 has not been detected from the side distance measurement sensor 26.

[0049] Next, in step S202, the object detection device 40 determines whether or not the object 80 is detected based on the signal from the lateral distance measuring sensor 26. If the object 80 is detected, the process of the object detection device 40 proceeds to step S204. If the object 80 is not detected, the process of the object detection device 40 proceeds to step S218.

[0050] In step S204 following step S202, the object detection device 40 creates or updates a histogram of the detection angles θcr acquired from when the object 80 was detected until the present time, as shown in FIG.

[0051] Next, in step S206, the object detection device 40 calculates the most frequently occurring detection angle θcr from the histogram created in step S204.

[0052] Here, it is assumed that the object 80 faces the positive direction of the X-axis and the Xc-axis. Furthermore, it is assumed that the vehicle 10 moves forward or backward, and the search wave from the side distance measuring sensor 26 is reflected at a part of the object 80 that is not a corner, for example, at the side of the object 80, before and after the movement of the vehicle 10. At this time, as shown in FIG. 13 and FIG. 14, since the side distance measuring sensor 26 moves together with the vehicle 10, the reflection point of the object 80 by the search wave from the side distance measuring sensor 26 also moves together with the vehicle 10. In addition, the line connecting the reflection points before and after the movement of the vehicle 10 becomes a straight line parallel to the X-axis and the Xc-axis. Therefore, at this time, there is no change in the detection angle θcr before and after the movement of the vehicle 10. Therefore, the most frequent detection angle θcr is, for example, 90 to 95 degrees.

[0053] Assume also that the object 80 faces the positive direction of the X-axis and the Xc-axis. Assume further that the vehicle 10 moves forward or backward, causing the search wave from the side distance measuring sensor 26 to be reflected by the side of the object 80 before the vehicle 10 moves, and the search wave from the side distance measuring sensor 26 to be reflected by the corner of the object 80 before the vehicle 10 moves. At this time, as shown in FIG. 15 and FIG. 16, since the side distance measuring sensor 26 moves together with the vehicle 10, the reflection point of the object 80 by the search wave from the side distance measuring sensor 26 also moves together with the vehicle 10. Also, the line connecting the reflection points before and after the movement of the vehicle 10 changes from a straight line parallel to the X-axis and the Xc-axis to a straight line intersecting the X-axis and the Xc-axis. Therefore, at this time, the change in the detection angle θcr is larger than when the reflection point of the object 80 is not a corner. Therefore, when the frequency of an angle shifted by a predetermined angle Δθ from the most frequent detection angle θcr is equal to or greater than a threshold value, the reflection point is determined to be a corner of the object 80, and the corner of the object 80 can be detected.

[0054] Therefore, in step S208 following step S206, the object detection device 40 calculates an angle by adding a predetermined angle Δθ to the most frequently detected angle θcr calculated in step S206, as shown in Fig. 12. In this way, the object detection device 40 calculates a first evaluation angle θe1. The object detection device 40 also calculates an angle by subtracting a predetermined angle Δθ from the most frequently detected angle θcr calculated in step S206. In this way, the object detection device 40 calculates a second evaluation angle θe2. Note that the above-mentioned predetermined angle Δθ is an angle set by an experiment, a simulation, or the like, and is, for example, 30 degrees.

[0055] Next, in step S210, the object detection device 40 calculates the frequency when the detection angle θcr is equal to or greater than the first evaluation angle θe1. Also, the object detection device 40 calculates the frequency when the detection angle θcr is equal to or less than the second evaluation angle θe2.

[0056] Next, in step S212, the object detection device 40 determines whether the frequency when the detection angle θcr is equal to or greater than the first evaluation angle θe1 ​​is equal to or greater than a first threshold value. Also, the object detection device 40 determines whether the frequency when the detection angle θcr is equal to or less than the second evaluation angle θe2 is equal to or greater than a second threshold value. In this way, the object detection device 40 detects the corner of the object 80 by determining whether the reflection point of the object 80 is a corner of the object 80. The first threshold value and the second threshold value are set by an experiment, a simulation, or the like.

[0057] Then, when the frequency when the detection angle θcr is equal to or greater than the first evaluation angle θe1 ​​is equal to or greater than the first threshold, the process of the object detection device 40 proceeds to step S214. When the frequency when the detection angle θcr is equal to or less than the second evaluation angle θe2 is equal to or greater than the second threshold, the process of the object detection device 40 proceeds to step S214. When the frequency when the detection angle θcr is equal to or greater than the first evaluation angle θe1 ​​is less than the first threshold and the frequency when the detection angle θcr is equal to or less than the second evaluation angle θe2 is less than the second threshold, the process of the object detection device 40 proceeds to step S216.

[0058] In step S214 following step S212, the frequency when the detection angle θcr is equal to or greater than the first evaluation angle θe1 ​​is equal to or greater than the first threshold, so the change in the detection angle θcr is large. Alternatively, the frequency when the detection angle θcr is equal to or less than the second evaluation angle θe2 is equal to or greater than the second threshold, so the change in the detection angle θcr is large. For this reason, the object detection device 40 determines that the reflection point is a corner of the object 80. In addition, the object detection device 40 multiplies the vehicle speed Vc acquired in step S100 by the control period τ. As a result, the object detection device 40 calculates the host vehicle movement amount ΔLc. Furthermore, the object detection device 40 calculates the position of the vehicle 10 in the absolute coordinate system Σ using the calculated host vehicle movement amount ΔLc, the attitude of the vehicle 10 acquired in step S100, and the position of the reflection point of the object 80 in the vehicle coordinate system Σc. The object detection device 40 also adds the position coordinates of the reflection point of the object 80 in the vehicle coordinate system Σc acquired in step S100 to the calculated position coordinates of the vehicle 10 in the absolute coordinate system Σ. As a result, the object detection device 40 calculates the position coordinates of the corner of the object 80 corresponding to the reflection point of the object 80 in the absolute coordinate system Σ. The object detection device 40 also outputs the calculated position of the corner of the object 80 in the absolute coordinate system Σ to the driving control device 50. Furthermore, the driving control device 50 calculates a route based on the position information of the corner, thereby calculating the shortest route that can avoid a collision between the vehicle 10 and the object 80. The driving control device 50 also automatically moves the vehicle 10 along the calculated route. After that, the processing of the object detection device 40 returns to step S200.

[0059] In step S216 following step S212, the frequency when the detection angle θcr is equal to or greater than the first evaluation angle θe1 ​​is less than the first threshold value, and the frequency when the detection angle θcr is equal to or less than the second evaluation angle θe2 is less than the second threshold value, so the change in the detection angle θcr is small. Therefore, the object detection device 40 determines that the reflection point is not the corner of the object 80. At this time, since the position of the corner of the object 80 is unknown, the driving control device 50 calculates, for example, a route for the vehicle 10 to move forward and backward. In addition, the driving control device 50 automatically moves the vehicle 10 along the calculated route. After that, the processing of the object detection device 40 returns to step S200.

[0060] In step S218 following step S202, since the object 80 has not been detected, the object detection device 40 resets the histogram created or updated in step S204. This enables the object detection device 40 to detect the corners of the object 80 the next time the object 80 is detected. Thereafter, the process of the object detection device 40 returns to step S200.

[0061] As described above, the object detection device 40 detects the corners of the object 80 on the sides of the vehicle 10. Next, the fact that the object detection device 40 can also detect the corners of the object 80 on the sides of the vehicle 10 in the second embodiment will be described.

[0062] In step S206, the object detection device 40 calculates the detection angle θcr that is most frequently detected from the time the object 80 is detected to the current time. The object detection device 40 also calculates a first evaluation angle θe1 ​​and a second evaluation angle θe2 whose absolute value of the difference from the most frequently detected angle θcr from the time the object 80 is detected to the current time is a predetermined angle Δθ. Furthermore, in steps S212 and S214, the object detection device 40 determines that the reflection point is a corner of the object 80 when the frequency at which the detection angle θcr is equal to or greater than the first evaluation angle θe1 ​​is equal to or greater than a first threshold value. In addition, in steps S212 and S214, the object detection device 40 determines that the reflection point is a corner of the object 80 when the frequency at which the detection angle θcr is equal to or less than the second evaluation angle θe2 is equal to or greater than a second threshold value. This makes it possible to detect the corner of the object 80 on the side of the vehicle 10. The object detection device 40 corresponds to the frequency calculation unit, the evaluation calculation unit, and the determination unit. The detection angle θcr corresponds to the relative angle of the reflection point of the object 80 with respect to the vehicle 10.

[0063] (Other embodiments) The present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. Furthermore, in each of the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where they are particularly clearly stated as essential or where they are clearly considered essential in principle.

[0064] The calculation unit, the determination unit, the change unit, etc., and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the calculation unit, the determination unit, the change unit, etc., and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the calculation unit, the determination unit, the change unit, etc., and the method thereof described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer.

[0065] In the above embodiment, the object 80 is a separate vehicle different from the vehicle 10. In contrast, the object 80 is not limited to being a separate vehicle, and may be, for example, a wall or the like.

[0066] In the above embodiment, the positive direction of each axis in the vehicle coordinate system Σc coincides with the positive direction of each axis in the absolute coordinate system Σ. In contrast, the positive direction of each axis in the vehicle coordinate system Σc is not limited to coincide with the positive direction of each axis in the absolute coordinate system Σ. When the positive direction of each axis in the vehicle coordinate system Σc intersects with the positive direction of each axis in the absolute coordinate system Σ, for example, the object detection device 40 performs coordinate conversion to make the positive direction of each axis in the vehicle coordinate system Σc coincide with the positive direction of each axis in the absolute coordinate system Σ. Thereafter, the object detection device 40 detects the corners of the object 80 by performing the above-mentioned series of processes, as in the above embodiment.

[0067] In the first embodiment, the object detection device 40 calculates the host vehicle movement amount ΔLc by multiplying the vehicle speed Vc by the control period τ in step S102. In contrast, the object detection device 40 is not limited to calculating the host vehicle movement amount ΔLc by multiplying the vehicle speed Vc by the control period τ in step S102. For example, the object detection device 40 may calculate the host vehicle movement amount ΔLc in step S102 by adding a value obtained by multiplying the vehicle speed Vc by the control period τ and a value obtained by multiplying the acceleration of the vehicle 10 by the square and one-half of the control period τ to the value obtained by multiplying the vehicle speed Vc by the control period τ.

[0068] In the first embodiment, in step S108, the object detection device 40 calculates the rate of change Rr by dividing the amount of change ΔLr by the amount of movement of the host vehicle ΔLc. In contrast, in step S108, the object detection device 40 is not limited to calculating the rate of change Rr by dividing the amount of change ΔLr by the amount of movement of the host vehicle ΔLc.

[0069] For example, in step S108, the object detection device 40 may calculate the rate of change Rr by dividing the amount of movement ΔLc of the vehicle by the amount of change ΔLr. In this case, the rate of change Rr when the reflection point is a corner of the object 80 is larger than when the reflection point is a side of the object 80. In addition, as the object angle θo increases, the amount of change ΔLr decreases, so the rate of change Rr increases. Therefore, in step S110 following step S108, the object detection device 40 increases the rate of change threshold Rr_th as the object angle θo increases. As a result, even if the rate of change Rr increases because the amount of change ΔLr decreases due to the increase in the object angle θo, the rate of change threshold Rr_th increases. For this reason, it is possible to suppress erroneous detection of the corner of the object 80. In addition, as shown in the flowchart of FIG. 17, in step S112 following step S110, the object detection device 40 determines whether the rate of change Rr is equal to or greater than the rate of change threshold Rr_th. In this way, the object detection device 40 detects the corner of the object 80 by determining whether or not the reflection point of the object 80 is a corner of the object 80. Even in this way, the same effects as in the first embodiment can be achieved.

[0070] Also, as shown in the flowchart of FIG. 18, in step S108 following step S106, the object detection device 40 may calculate the absolute value |ΔLc-ΔLr| of the difference between the vehicle movement amount ΔLc and the change amount ΔLr. In this case, similar to the above, the absolute value |ΔLc-ΔLr| when the reflection point is a corner of the object 80 is larger than when the reflection point is a side of the object 80. Also, as the object angle θo increases, the change amount ΔLr decreases, so the absolute value |ΔLc-ΔLr| increases. Therefore, in step S110 following step S108, the object detection device 40 increases the difference threshold value ΔL_th as the object angle θo increases. As a result, even if the absolute value |ΔLc-ΔLr| increases because the change amount ΔLr decreases due to the increase in the object angle θo, the change rate threshold value Rr_th increases. For this reason, it is possible to suppress erroneous detection of the corner of the object 80. In step S112 following step S110, the object detection device 40 determines whether the absolute value |ΔLc-ΔLr| is equal to or greater than the difference threshold ΔL_th. In this way, the object detection device 40 detects the corner of the object 80 by determining whether the reflection point of the object 80 is a corner of the object 80. This also provides the same effects as the first embodiment. The object detection device 40 corresponds to a difference calculation unit.

[0071] In the above embodiment, the object detection device 40 calculates the position of the vehicle 10 in the absolute coordinate system Σ by using the attitude of the vehicle 10 and the host vehicle movement amount ΔLc. In contrast, the object detection device 40 is not limited to calculating the position of the vehicle 10 in the absolute coordinate system Σ by using the attitude of the vehicle 10, the position of the reflection point of the object 80 in the vehicle coordinate system Σc, and the host vehicle movement amount ΔLc. The object detection device 40 may acquire the position of the vehicle 10 in the absolute coordinate system Σ from a GNSS receiver (not shown) or the like. [Explanation of symbols]

[0072] 10 Vehicles 15 System 22 Gyro sensor 24 Vehicle speed sensor 26 Side distance sensor 40 Object detection device 50 Operation control device 80 Object

Claims

1. An object detection device for use in a vehicle, the object detection device including a distance measuring sensor (26) that detects an object (80) by transmitting a search wave to a side of the vehicle (10) and receiving the search wave reflected by the object, A frequency calculation unit (S206) that calculates a relative angle (θcr) of a reflection point of the object with respect to the vehicle that occurs most frequently from the time the object is detected to the current time; an evaluation calculation unit (S208) that calculates a first evaluation angle (θe1) whose absolute value of a difference from the most frequently detected relative angle from the time the object was detected to the present time is a predetermined angle Δθ and a second evaluation angle (θe2) that is smaller than the first evaluation angle; a determination unit (S212, S214) that determines that the reflection point is a corner of the object when the frequency at which the relative angle is equal to or greater than the first evaluation angle is equal to or greater than a first threshold, and that determines that the reflection point is a corner of the object when the frequency at which the relative angle is equal to or less than the second evaluation angle is equal to or greater than a second threshold; An object detection device comprising:

2. An object detection device for use in a vehicle, the object detection device including a distance measuring sensor (26) for detecting an object (80) by transmitting a search wave to the side of the vehicle (10) and receiving the search wave reflected by the object, a frequency calculation unit (S206) that calculates the relative angle (θ cr ) of the reflection point of the object with respect to the vehicle that occurs most frequently from the time the object is detected until the current time; an evaluation calculation unit (S208) that calculates a first evaluation angle (θe1) whose absolute value of the difference from the most frequently detected relative angle from the time the object was detected to the present time is a predetermined angle Δθ and a second evaluation angle (θe2) that is smaller than the first evaluation angle; and an object detection program that functions as a determination unit (S212, S214) that determines that the reflection point is a corner of the object when the frequency when the relative angle is equal to or greater than the first evaluation angle is equal to or greater than a first threshold, and determines that the reflection point is a corner of the object when the frequency when the relative angle is equal to or less than the second evaluation angle is equal to or greater than a second threshold.

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