Object determination device and object determination method

Abstract

To provide an object determination device and an object determination method capable of accurately determining an object.SOLUTION: An object determination device includes a calculation unit that calculates a difference between times of flight of a plurality of ultrasonic waves reflected by an object and received by a plurality of sonar devices, or a difference between distances corresponding to the times of flight, and a determination unit that determines a type of the object on the basis of the difference.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present disclosure relates to an object determination device and an object determination method. [Background technology]

[0002] In existing automatic braking systems, the reflected wave waveform is normalized according to ultrasonic attenuation characteristic information corresponding to the distance from the vehicle to the object that reflected the ultrasonic wave, and if the reflection intensity is equal to or greater than a predetermined threshold, it is determined that an object is present. In this case, by setting the threshold to be equal to or greater than the intensity of the reflected wave from a curb that does not require braking, it is possible to detect walls and other objects other than curbs (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-142252 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the strength of the reflected waves is also weaker for objects with complex shapes, such as people. Therefore, even for such objects, the strength of the reflected waves falls below the threshold, which may prevent the brakes from operating and cause the vehicle to collide with the object.

[0005] On the other hand, if the threshold is set to a value less than the strength of the waves reflected from the curb, the brakes will be applied to the person, and a collision with the person can be avoided, but the brakes will also be applied to the curb.

[0006] Non-limiting examples of the present disclosure contribute to providing a determination device and a determination method that can accurately determine an object. [Means for solving the problem]

[0007] For this purpose, one aspect of the object determination device according to the present disclosure includes a calculation unit that calculates the difference in time of flight (TOF) of multiple ultrasonic waves reflected by an object and received by multiple sonar devices in one transmission cycle in response to transmissions from a certain sonar device, or the difference in distance corresponding to the TOF, and a determination unit that determines the type of the object based on the difference.

[0008] Furthermore, one aspect of the object determination method according to the present disclosure calculates the difference between the TOFs (Time of Flight) of multiple ultrasonic waves received by multiple sonar devices and reflected by an object, or the distances corresponding to the TOFs, and determines the type of the object based on the difference. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to accurately determine an object. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing brake control thresholds in current sonar systems. [Figure 2] FIG. 2 is a diagram showing the installation position of a sonar device. [Figure 3] FIG. 10 is a diagram showing the reflection of ultrasonic waves by a pedestrian. [Figure 4A] FIG. 10 is a diagram showing examples of pedestrian dimensions. [Figure 4B] FIG. 2 is a diagram showing the positional relationship between a pedestrian and a vehicle. [Figure 5A] FIG. 10 is a diagram showing the difference in reflection points in the X direction. [Figure 5B] FIG. 10 is a diagram illustrating the influence of differences in reflection points in the X direction. [Figure 6A] FIG. 10 is a diagram showing the difference in reflection points in the Y direction. [Figure 6B] FIG. 10 is a diagram illustrating the influence of differences in reflection points in the Y direction. [Figure 7A] FIG. 10 is a diagram showing the difference in reflection points in the Z direction. [Figure 7B]FIG. 10 is a diagram illustrating the influence of differences in reflection points in the Z direction. [Figure 8A] FIG. 10 is a diagram showing the reflection of ultrasonic waves by a pedestrian. [Figure 8B] FIG. 10 is a diagram showing the difference value of TOF that changes over time. [Figure 9] FIG. 10 is a diagram showing fluctuations in the difference value of TOF for a pedestrian. [Figure 10] FIG. 10 is a diagram showing the reflection of ultrasound waves by a curb; [Figure 11A] FIG. 2 is a diagram showing the positional relationship between a vehicle and a curb; [Figure 11B] FIG. 2 is a diagram showing the positional relationship between a vehicle and a curb; [Figure 11C] FIG. 10 is a diagram showing the maximum value of the TOF difference for a curb; [Figure 12A] FIG. 2 is a diagram showing the wave transmission cycle of each sonar device. [Figure 12B] FIG. 10 is a diagram showing fluctuations in the difference value of TOF for a curb; [Figure 13] FIG. 2 is a diagram showing the positional relationship between a pole and a vehicle. [Figure 14A] FIG. 2 is a diagram showing the positional relationship between a pole and a vehicle. [Figure 14B] FIG. 2 is a diagram showing the positional relationship between a pole and a vehicle. [Figure 14C] FIG. 10 is a diagram showing the maximum value of the TOF difference for a pole. [Figure 15] FIG. 10 is a diagram showing fluctuations in the difference value of TOF for a pole. [Figure 16] 1 is a diagram illustrating an example of a configuration of an object determination device according to a first embodiment. [Figure 17] 5 is a flowchart showing an example of an object determination process according to the first embodiment. [Figure 18] FIG. 10 is a diagram illustrating an example of the configuration of an object determining device according to a second embodiment. [Figure 19] 10 is a flowchart showing an example of an object determination process according to the second embodiment. [Figure 20] FIG. 10 is a diagram illustrating an example of the configuration of an object determining device according to a third embodiment. [Figure 21] 11 is a flowchart showing an example of an object determination process according to the third embodiment. [Figure 22] FIG. 10 is a diagram showing the reflection of ultrasonic waves by a pedestrian. [Figure 23] FIG. 10 is a diagram showing the reflection of ultrasonic waves by a pedestrian. [Figure 24] FIG. 10 is a diagram showing an example of data used to determine whether or not an object is a pedestrian. [Figure 25] FIG. 10 is a diagram illustrating a method for calculating an estimated distance from a sonar device to a pedestrian, which is used to determine whether the pedestrian is a pedestrian. [Figure 26] 10A and 10B are diagrams illustrating calculation results of the difference between the measured distance and the estimated distance for a moving object. [Figure 27] FIG. 10 is a diagram showing fluctuations in the difference value of TOF for a still doll. [Figure 28] FIG. 10 is a diagram illustrating an example of the configuration of an object determining device according to a fourth embodiment. [Figure 29] 11 is a flowchart showing an example of an object determination process according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the components, the arrangement and connection of each component, and each step and the order of each step shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0012] Furthermore, each drawing is a schematic diagram and is not necessarily a precise illustration. In each drawing, substantially the same components are denoted by the same reference numerals, and redundant explanations will be omitted or simplified.

[0013] First, let us explain the current state of sonar systems. As shown in Figure 1, it is generally desirable for a vehicle's Autonomous Emergency Braking to operate when it comes to tall objects.

[0014] Currently, a threshold is set corresponding to the strength of the ultrasonic waves reflected by the curb, and the brakes are activated when the reflected ultrasonic strength is above this threshold. For example, the brakes will not be activated for steps of 10cm or 15cm or less, but will be activated for steps higher than this.

[0015] However, there are tall objects such as cylinders and pedestrians with a diameter of about Φ30 that have a reflection intensity below the threshold. In this case, if a threshold (second threshold) smaller than the threshold (first threshold) for the curb is set to avoid a collision with the cylinder or pedestrian, the brakes will be applied when the vehicle hits the curb.

[0016] 2, sonar devices are provided at the front and rear of the vehicle 11. The sonar devices are equipped with a TOF (Time Of Flight) sensor that transmits ultrasonic waves, receives the waves reflected by an object, and measures the distance to the object from the time of flight of the ultrasonic waves.

[0017] In this embodiment, the explanation will be given using as examples a sonar device (hereinafter referred to as RRC) 12 located in the center of the rear right side of a vehicle 11, a sonar device (hereinafter referred to as RLC) 13 located in the center of the rear left side, a sonar device (hereinafter referred to as RR) 14 located on the rear right side, and a sonar device (hereinafter referred to as RL) 15 located on the rear left side.

[0018] For example, information on the TOF of ultrasound is calculated in each of the following cases. (a-1) When ultrasonic waves transmitted from the RRC 12 are received by the RRC 12, or by the RLC 13 and the RR 14. This may further include when the ultrasonic waves are received by the RL 15. (a-2) When ultrasonic waves transmitted from the RLC 13 are received by the RLC 13, or by the RLC 12 and the RL 15. This may further include when the ultrasonic waves are received by the RR 14. (a-3) When ultrasonic waves transmitted from RR14 and RL15 are received by RR14, RL15, RRC12, and RLC13.

[0019] Furthermore, the coordinate information of the object is calculated by triangulation in each of the following cases. (b-1) When ultrasonic waves transmitted from RR14 are received by RR14 and RRC12 (S0 coordinates), and when ultrasonic waves transmitted from RL15 are received by RR15 and RLC13 (S5 coordinates). (b-2) When ultrasonic waves transmitted from RRC12 are received by RRC12 and RR14 (S1 coordinates), and when ultrasonic waves transmitted from RRC12 are received by RLC13 (S2 coordinates). (b-3) When ultrasonic waves transmitted from RLC13 are received by RLC13 and RRC12 (S3 coordinate), and when ultrasonic waves transmitted from RLC13 are received by RL15 (S4 coordinate).

[0020] When analyzing the TOF of ultrasonic waves calculated in this manner when a person is the target, it is found that the TOF varies in each of the cases (a-1) to (a-3) even for the same person. It is also found that the coordinates of S0, S1, S4, and S5 vary in the width direction of the vehicle 11. For this reason, it is estimated that when measurements (a-1) to (a-3) and (b-1) to (b-3) are performed, the complex shape of a person likely causes the positions of the reflection points where ultrasonic waves are reflected to differ.

[0021] Let us consider this point in more detail. As shown in Figure 3, the reflection point of the pedestrian 21 changes depending on the sonar device that transmits the ultrasonic waves, the sonar device that receives the reflected waves, and the position or posture of the pedestrian 21. Furthermore, because both the vehicle 11 and the pedestrian 21 move, it is extremely difficult to determine whether the target is a pedestrian 21 based on the TOF of the ultrasonic waves received by a single sonar device. Furthermore, the strength of the reflected waves from the pedestrian 21 is weak, and the shape of the pedestrian 21 is complex, making it even more difficult to detect the pedestrian 21.

[0022] Therefore, the technology disclosed herein focuses on the following points. Here, in each transmission period in which TOF is measured, one sonar device transmits ultrasonic waves and multiple sonar devices receive them. In the following, TOF will be used to represent the flight time or flight distance (distance to the target) of the sound waves to the target measured by the TOF sensor of the sonar device.

[0023] In most cases, the reflection points from the human body are different, and the TOF of the ultrasound received by the first sonar device is used as the TOF sonar1 The TOF of the ultrasonic wave received by the second sonar device is TOF sonar2 Then, we can see that the following relationships a and b exist.

[0024] a. The two TOFs are different.

number

number

[0025] The first point of the technology of the present disclosure is that such a difference value of TOF is smaller than a predetermined threshold value.

[0026] Furthermore, because vehicles 11 and pedestrians 21 move, their reflective surfaces are not stable. As a result, the TOFs detected by each sonar device fluctuate randomly within a predetermined range over time. This is the second key feature of the technology of the present disclosure.

[0027] Furthermore, the geometric shape of a pedestrian 21 is complex, and the reflection points of ultrasonic waves transmitted from one sonar device and received by that sonar device will usually be different from those of ultrasonic waves transmitted from another sonar device and received by another sonar device.

[0028] Additionally, if the target object is a pedestrian 21, the reflection site (head, shoulders, stomach, thighs, knees, feet, etc.) will change depending on the distance to the pedestrian 21 and the posture of the pedestrian 21. For example, as shown in Figure 3, when the pedestrian 21 walks in the Y direction, the changes in distance of the reflection site in the X, Y, and Z directions caused by the movement of the arms and legs are approximately 0.6 m, 0.9 m, and 1.8 m, respectively. Due to such changes in the reflection site in the X, Y, and Z directions, the difference in TOF of the ultrasonic waves between different sonar devices will change randomly within a predetermined range.

[0029] Below, we will use two sonar devices, RRC12 and RLC13, as examples to explain in detail how the difference in the reflecting area in the X, Y, and Z directions affects TOF.

[0030] As shown in FIG. 4A, the pedestrian 21 has a width dimension (X direction) of 0.6 m, a front-rear dimension (Y direction) of 0.8 m, and a height dimension (Z direction) of 1.8 m.

[0031] In order to understand the equations for the distances b1 and b2 shown below, the positional relationship between the reflection points 22 and 23 will be explained assuming that the pedestrian 21 is a cube 24, as shown in FIG. 4B. Here, the difference diff in the TOF of the ultrasonic waves between the RRC 12 and the RLC 13 is calculated by dividing the TOF of the ultrasonic waves received by the RRC 12 by the TOF RRC The TOF of the ultrasound received by RLC13 is TOF RLC Then, diff=TOF RLC -TOFRRC This becomes:

[0032] Here, the maximum value of the difference diff in TOF between two reflection points 22 and 23 whose coordinates differ by Δx, Δy, and Δz in the X, Y, and Z directions is the distance between the pedestrian 21 and the vehicle 11, the dimensions Δx, Δy, and Δz of the pedestrian 21 in the X, Y, and Z directions, and the distance d between the RRC 12 and the RLC 13. s Δx, Δy, and Δz correspond to the width, thickness, and height of the pedestrian 21.

[0033] In the following, TOF RRC ,TOF RLC represents a value obtained by dividing the distance corresponding to the time it takes for the ultrasonic waves transmitted by the RRC 12 to be reflected by the pedestrian 21 and received by the RRC 12 and RLC 13 by two.

[0034] First, TOF RRC is smallest when the ultrasonic wave is reflected by the reflection point 22 closest to the vehicle 11. For example, if a is the distance from the RRC 12 to the reflection point 22 and D is the distance from the vehicle 11 to the pedestrian 21, then min TOF RRC =a=D.

[0035] Also, TOF RLC The maximum value of is expressed as follows:

number

[0036] Here, b1 and b2 are expressed as follows:

number

number

[0037] Therefore, the maximum value of the TOF difference diff between the reflection points 22 and 23 is as follows:

number

[0038] Furthermore, when the equation for the maximum value of the difference diff is partially differentiated with respect to Δx, Δy, and Δz, the following equation is obtained.

number

[0039] From the results of these partial differentiations, Δx has the greatest influence on the maximum value of the difference diff, and Δy and Δz have the same influence. However, when the object is a pedestrian 21, Δz, which corresponds to the height of the pedestrian 21, is greater than Δy, which corresponds to the thickness of the pedestrian 21, so the influence on the maximum value of the difference diff is greatest in the order of Δx, Δz, and Δy.

[0040] Next, we will explain the influence of differences in the positions of reflection points in the X direction when detecting a pedestrian 21 with the dimensions shown in Fig. 5A. Here, we will assume that the dimension of the pedestrian 21 in the width direction (X direction) is 0.6 m, the dimension in the front-to-back direction (Y direction) is 0.8 m (corresponding to the case where the arms and legs are spread apart), and the dimension in the height direction (Z direction) is 1.8 m.

[0041] First, TOF RRC is minimum when the ultrasonic wave is reflected at the reflection point 22 closest to the vehicle 11. For example, min TOF RRC =a=D.

[0042] Also, TOF RLC The maximum value of is expressed as follows: where W is the width of the pedestrian 21, and corresponds to the above-mentioned Δx.

number

[0043] Therefore, the maximum value of the difference diff due to the positional difference in the X direction between the positions of the reflection points 22 and 23 is as follows:

number

[0044] 5B shows the maximum value of the difference diff (max_diff), which changes depending on the distance D from the vehicle 11 to the pedestrian 21. The maximum value of the difference diff is large, and the difference in position in the X direction between the reflection points 22 and 23 is almost reflected in the maximum value of the difference diff. Note that the actual distance between the reflection points 22 and 23 is often smaller than the width W of the pedestrian 21.

[0045] Next, we will explain the influence of the difference in the position of the reflection points in the Y direction when detecting a pedestrian 21 with the dimensions shown in Fig. 6A. Here, we also assume that the pedestrian 21 has a width dimension (X direction) of 0.6 m, a front-to-back dimension (Y direction) of 0.8 m, and a height dimension (Z direction) of 1.8 m.

[0046] First, TOF RRC is minimum when the ultrasonic wave is reflected at the reflection point 22 closest to the vehicle 11. For example, min TOF RRC =a=D.

[0047] Also, TOF RLC The maximum value of is expressed as follows: where T is the width of the pedestrian 21, and corresponds to the above-mentioned Δy.

number

[0048] Therefore, the maximum value of the difference diff due to the difference in the Y direction between the positions of the reflection points 22 and 23 is as follows:

number

[0049] 6B shows the maximum value of the difference diff (max_diff), which changes depending on the distance D from the vehicle 11 to the pedestrian 21. The influence of the positional difference in the Y direction between the reflection points 22 and 23 changes depending on the distance D between the pedestrian 21 and the vehicle 11, and the closer the distance, the greater the influence.

[0050] Next, we will explain the influence of differences in the positions of reflection points in the Z direction when detecting a pedestrian 21 with the dimensions shown in Fig. 7A. Here, we also assume that the pedestrian's dimensions in the width direction (X direction) are 0.6 m, the dimensions in the front-to-back direction (Y direction) are 0.8 m, and the dimensions in the height direction (Z direction) are 1.8 m.

[0051] First, TOF RRC is minimum when the ultrasonic wave is reflected at the reflection point 22 closest to the vehicle 11. For example, min TOF RRC =a=D.

[0052] Also, TOF RLC The maximum value of d is expressed as follows: where H is the height of the pedestrian 21, which corresponds to the above-mentioned Δz. s is the distance between RRC12 and RLC13, and h s is the height at which the RRC 12 and the RLC 13 are installed.

number

[0053] Therefore, the maximum value of the difference diff due to the positional difference in the Z direction between the positions of the reflection points 22 and 23 is as follows:

number

[0054] 7B shows the maximum value of the difference diff (max_diff), which changes depending on the distance D from the vehicle 11 to the pedestrian 21. The influence of the difference in position in the Z direction between the reflection points 22 and 23 changes depending on the distance D between the pedestrian 21 and the vehicle 11, and the closer the distance, the greater the influence.

[0055] Next, the temporal fluctuation of the difference diff in the TOF of the ultrasonic waves will be explained. Consider the case where a pedestrian 21' is located behind the vehicle 11, as shown in FIG.

[0056] As shown by the dotted line, the ultrasonic waves transmitted from the RR 14 are reflected by a reflection point 26 on the right elbow of the pedestrian 21', and the reflected waves are received by the RRC 12. The height h1 of the reflection point on the right elbow is 1.1 m.

[0057] Also, assume that ultrasonic waves transmitted from the RRC 12 in another transmission frame are reflected by a reflection point 27 on the right thigh of a pedestrian 21', and the reflected waves are received by the RLC 13. The height h2 of the reflection point on the right thigh is 0.7 m.

[0058] Furthermore, the distance between RLC13 and RL15 and the distance between RRC12 and RR14 are 0.4 m, the distance between RRC12 and RLC13 is 0.5 m, the installation height of RR14 and RL15 is 0.5 m, the installation height of RRC12 and RLC13 is 0.55 m, and the differences Δx, Δy, and Δz in the X, Y, and Z directions between the two reflection points 26 and 27 are 0 m, 0.2 m, and 0.4 m, respectively.

[0059] In this case, the TOF of the ultrasound received by RRC12 RRC , and TOF of ultrasound received by RLC13 RLC is expressed by the following equation, which is similar to the above equation (1).

number

[0060] FIG. 8B shows the difference value (TOF) of the TOF that changes depending on the distance D from the vehicle 11 to the pedestrian 21′. RLC -TOF RRC ) is shown. It can be seen that the difference value of TOF is small, and as time passes and the vehicle 11 approaches the pedestrian 21′, the difference value of TOF fluctuates as the distance D decreases.

[0061] Figure 9 shows a graph of the time variation of the TOF difference. For example, transmissions are made in the order of RRC12, RLC13, and RR14 / RL15 in a 50 ms cycle, and after simultaneous transmissions from both RR14 and RL15, transmissions are made again from RRC12. RR14 / RL15 or RR / RL refer to sonar devices in which two devices transmit simultaneously in one transmission cycle.

[0062] In each ultrasonic wave transmission frame, the difference value of TOF increases as the distance D decreases according to the above-mentioned formula (1), but remains smaller than a predetermined threshold. Furthermore, it can be seen that the reflection points change randomly due to irregularities in the shape of the pedestrian 21, causing the difference value of TOF to fluctuate within a predetermined range over time.

[0063] Next, we will explain the difference in TOF when ultrasonic waves are reflected by a curb. As shown in Figure 10, the reflection from the curb 31 is basically a reflection from a flat surface, and if the reflecting surface is parallel to the line connecting the two sonar devices, the coordinates of the two reflecting points in the X direction are the same (Δx = 0).

[0064] Furthermore, the first wave received by the sonar device is a reflected wave that reaches the sonar device via the shortest route, and since the height of the curb 31 is less than 0.2 m, the coordinates of the two reflection points in the Z direction are also approximately the same (Δz = 0).

[0065] Here, as shown in FIGS. 11A and 11B, the TOF of the ultrasonic waves received by the RRC 12 is expressed as TOF RRC The TOF of the ultrasound received by RLC13 is TOF RLC Then, diff=TOF RLC -TOF RRC This becomes:

[0066] As mentioned above, in the case of the curbstone 31, the reflector is a surface, and when the curbstone 31 is perpendicular to the direction of travel of the vehicle, the differences Δx and Δz in the X and Z directions between the two reflection points 32 and 33 are approximately 0, so Δx = Δz = 0.

[0067] Furthermore, since the first wave received by the sonar device is a reflected wave from the shortest route, Δy is 1 / 2 the distance between RRC12 and RLC13.

number

[0068] First, TOF RRC is smallest when the ultrasonic wave is reflected by the reflection point 32 closest to the vehicle 11. For example, if a is the distance from the RRC 12 to the reflection point 32 and D is the distance from the vehicle 11 to the curb 31, then min TOF RRC =a=D.

[0069] Also, TOF RLC The maximum value of is expressed as follows:

number

[0070] Therefore, the maximum value of the difference diff due to the positional difference in the Y direction between the positions of the reflection points 32 and 33 is as follows:

number

[0071] 11C shows the maximum value of the difference diff (max_diff) that changes depending on the distance D from the vehicle 11 to the curb 31. It can be seen that the maximum value of the difference diff of the TOF for the curb 31 is much smaller than the maximum value of the difference of the TOF for the person 21.

[0072] As shown in Figure 12A, the sonar device transmits waves repeatedly at 50 ms intervals in the following order: RRC12, RLC13, both RL15 and RR14, RRC12, ... Figure 12B shows a graph of the time variation of the TOF difference for the curbstone 31 in this case, calculated using the same method as in Figure 9. The TOF difference value increases as the distance D decreases, according to the above-mentioned equation (2), but it can be seen that the range of fluctuation is much smaller than in the case of the pedestrian 21 shown in Figure 9.

[0073] Next, we will explain the difference in TOF when ultrasonic waves are reflected by a pole. As shown in Figures 13, 14A, and 14B, the first wave received by a sonar device is a reflection that reaches the sonar device via the shortest route. Furthermore, because the shape of the pole 41 is cylindrical, the reflection point when ultrasonic waves transmitted from one sonar device are received by that sonar device is approximately the same as the reflection point when ultrasonic waves transmitted from that sonar device are received by another sonar device.

[0074] Therefore, when the object to be detected is the pole 41, the reflection point is the same, so there is no difference in the position of the reflection point, and it is acceptable to set Δx = Δy = Δz = 0. In this case, the factor that affects the difference in TOF of the ultrasound waves received by the RRC 12 and the RLC 13 is the relative positional relationship between the pole 41, RRC 12, and RLC 13.

[0075] In this case, the TOF of the ultrasound received by RRC12 RRC , and TOF of ultrasound received by RLC13 RLC becomes:

number

[0076] Therefore, the difference diff between the TOFs of the ultrasonic waves received by RRC12 and RLC13 is as follows:

number

[0077] Here, TOF RRC The minimum value of is the distance between the pole 41 and the vehicle 11, so min TOF RRC =a=D. Also, TOF RLC The maximum value of d is the interval between RRC12 and RLC13. s This gives us the following:

number

[0078] Therefore, the maximum value of the TOF difference diff is as follows:

number

[0079] 14C shows the maximum value of the difference diff (max_diff) that changes depending on the distance D from the vehicle 11 to the pole 41. It can be seen that the maximum value of the difference diff of the TOF for the pole 41 is much smaller than the maximum value of the difference of the TOF for the pedestrian 21.

[0080] Fig. 15 shows a graph of the time variation of the TOF difference for pole 41, calculated in the same way as in Fig. 9. The TOF difference value increases somewhat as distance D decreases according to the above-mentioned formula (3), but it can be seen that the increase is only about a few centimeters, and the range of fluctuation is much smaller than in the case of pedestrian 21 shown in Fig. 9.

[0081] An embodiment implemented based on this knowledge will be described in detail below.

[0082] (Embodiment 1) 16 is a diagram showing an example of the configuration of a determination device 51 according to embodiment 1. The determination device 51 includes a plurality of sonar devices 52, an input unit 53, a difference calculation unit 54, a shortest distance calculation unit 55, an object threshold calculation unit 56, an object determination unit 57, and an output unit 58.

[0083] Each sonar device 52 transmits ultrasonic waves, receives ultrasonic waves reflected by a detection target, and outputs information on the reflection intensity corresponding to the TOF. Each sonar device 52 corresponds to the RRC 12, RLC 13, RR 14, and RL 15 described above.

[0084] The input unit 53 receives input of the TOF and reflection intensity information output from each sonar device 52. The difference calculation unit 54 acquires information such as the number of sonar devices from sonar installation information 59 stored in the memory unit, calculates the difference between the TOFs output from each sonar device 52, and outputs the result to the object determination unit 57.

[0085] The shortest distance calculation unit 55 calculates the shortest distance from the vehicle to the object from the information of the first wave reflected by the object, and outputs the result to the object threshold calculation unit 56 .

[0086] The object threshold calculation unit 56 calculates a threshold value for the difference in TOF for each object corresponding to the shortest distance calculated by the shortest distance calculation unit 55, based on the object threshold information 60 stored in the storage unit. Here, the object threshold information 60 stores information on the shortest distance and the threshold value for the difference in TOF, associated with the type of object. By changing the threshold value according to the shortest distance, the object can be accurately determined.

[0087] The object determination unit 57 compares each difference value calculated by the difference calculation unit 54 with the threshold value of the TOF difference of each object calculated by the object threshold calculation unit 56, and determines the type of object.

[0088] The output unit 58 outputs information on the determination result by the object determination unit 57 to an ECU (Electronic Control Unit) of the vehicle, etc. This information is used for controlling the autonomous emergency braking of the vehicle, etc.

[0089] Next, a description will be given of the object type determination process performed by the determination device 51. As shown in Fig. 17, first, the object threshold calculation unit 56 of the determination device 51 acquires the sonar mounted information 59 and the object threshold information 60 (step S1).

[0090] The input unit 53 receives the reflected intensity P of the ultrasonic waves measured by each sonar device 52. i (i=1,...,N) and the distance TOFi An input of information (i=1, . . . , N) is accepted (step S2). Here, it is assumed that there are N sonar devices.

[0091] Next, the difference calculation unit 54 calculates the reflection intensity P i It is determined whether or not the threshold value Th1 is greater than the threshold value Th1 and less than the threshold value Th2 (step S3). The threshold values ​​Th1 and Th2 are set in advance.

[0092] Reflection intensity P i If is not within the range of being greater than the threshold value Th1 and smaller than the threshold value Th2 (step S3, NO), the process of step S2 is executed again.

[0093] Reflection intensity P i is greater than the threshold value Th1 and less than the threshold value Th2 (step S3, YES), the difference calculation unit 54 calculates the difference value diff(i, j) (i, j=1, . . . , N) of each TOFi, and the shortest distance calculation unit 55 calculates the distance TOF i Minimum TOF min (Step S4) where diff, (i, j) = |TOF i -TOF j |(i≠j).

[0094] Thereafter, the object threshold calculation unit 56 calculates the minimum distance TOF min The threshold value of the difference in TOF of the object corresponding to the object is calculated based on the object threshold information 60 (step S5). In this example, the objects are the pedestrian 21, the curb 31, and the pole 41. min The corresponding threshold Th ped , Th curb , Th pоle is set.

[0095] Then, the object determination unit 57 determines whether all of the difference values ​​diff(i, j) (i, j=1, . . . , N) are equal to or smaller than the threshold value Th of the pole 41. pоle It is determined whether it is smaller than (step S6).

[0096] All of the difference values ​​diff(i,j) are within the threshold Th of pole 41. pоle If the calculated position coordinates are smaller than the predetermined range (step S6, YES), the object determination unit 57 further calculates the S0 coordinate, the S1 coordinate, the S4 coordinate, and the S5 coordinate using the triangulation described above (step S13), and determines whether the y-axis (vehicle width direction) of the calculated position coordinates varies beyond a predetermined range (step S14). If the calculated position coordinates do not vary (step S14, NO), the object is determined to be a pole 41 (step S15), and the output unit 58 outputs the determination result (step S10). If the calculated position coordinates vary (step S14, YES), the process proceeds to step S7.

[0097] If any of the difference values ​​diff(i,j) (i,j=1, ,N) is equal to or exceeds the threshold value Th of pole 41, pоle If the difference values ​​diff(i, j) (i, j=1, . . . , N) are all equal to or greater than the threshold value Th of the curb 31 (step S6, NO), or if the calculated y-axis (vehicle width direction) values ​​of the S0 coordinate, S1 coordinate, S4 coordinate, and S5 coordinate vary beyond a predetermined range, the object determination unit 57 determines whether all of the difference values ​​diff(i, j) (i, j=1, . . . , N) are equal to or greater than the threshold value Th of the curb 31. curb It is determined whether it is smaller than (step S7).

[0098] All of the difference values ​​diff(i,j) (i,j=1,...,N) are within the threshold Th of curb 31. curb If it is smaller than (step S7, YES), the object determination unit 57 determines that the object is the curbstone 31 (step S12), and the output unit 58 outputs the determination result (step S10).

[0099] If any of the difference values ​​diff(i,j) (i,j=1, ,N) is equal to the threshold value Th of the curb 31, curb If the difference values ​​diff(i, j) (i, j=1, . . . , N) are all equal to or greater than the threshold value Th of the pedestrian 21 (step S7, NO), the object determination unit 57 ped It is determined whether it is smaller than (step S8).

[0100] All of the difference values ​​diff(i,j) (i,j=1, ,N) are within the threshold Th of the pedestrian 21. ped(step S8, YES), the object determination unit 57 determines that the object is a pedestrian 21 (step S11), and the output unit 58 outputs the determination result (step S10).

[0101] If any of the difference values ​​diff(i,j) (i,j=1, ,N) is equal to or exceeds the threshold value Th of the pedestrian 21, ped If so (step S8, NO), the object determination unit 57 determines that the object is something other than the pedestrian 21, the curb 31, or the pole 41 (step S9), and the output unit 58 outputs the determination result (step S10).

[0102] In this way, by determining the object based on the difference in the distance to the object measured by each sonar device, the determination device 51 can accurately determine the object.

[0103] (Embodiment 2) Fig. 18 is a diagram showing an example of the configuration of a determination device 61 according to embodiment 2. As shown in Fig. 18, the determination device 61 further includes a cache unit 62 in addition to the configuration of the determination device 51 according to embodiment 1.

[0104] The cache unit 62 receives information on the difference value of TOF at each time t from the difference calculation unit 54, and buffers the difference values ​​of TOF of the past M transmission frames.

[0105] The object determination unit 57 calculates the maximum difference value among the TOF difference values ​​of the past M transmission wave frames buffered in the cache unit 62. As shown in Fig. 12A, the sonar device that transmits waves is switched for each transmission wave frame. The object determination unit 57 then compares the maximum difference value with the TOF difference threshold value for each object to determine the object.

[0106] Next, a description will be given of the object type determination process performed by the determination device 61. As shown in Fig. 19, first, the object threshold calculation unit 56 of the determination device 61 acquires the sonar mounted information 59 and the object threshold information 60 (step S21).

[0107] The input unit 53 receives the ultrasonic reflection intensity P measured by each sonar device 52 at time t. i (i=1,...,N) and the distance TOF i The input of information (t) (i=1, . . . , N) is accepted (step S22). Here, it is assumed that there are N sonar devices.

[0108] Next, the difference calculation unit 54 calculates the reflection intensity P i It is determined whether or not the threshold value Th1 is greater than the threshold value Th1 and less than the threshold value Th2 (step S23). The threshold values ​​Th1 and Th2 are set in advance.

[0109] Reflection intensity P i If is not within a predetermined range that is greater than the threshold value Th1 and less than the threshold value Th2 (step S23, NO), the process of step S22 is executed again.

[0110] Reflection intensity P i is greater than the threshold value Th1 and is within a predetermined range less than the threshold value Th2 (step S23, YES), the difference calculation unit 54 calculates the difference between the TOFs i (t) (i, j = 1,..., N) is calculated, and the shortest distance calculation unit 55 calculates the distance TOF i (t) minimum TOF min and outputs it to the object threshold calculation unit 56. The object threshold calculation unit 56 calculates the minimum value TOF of the input distances. min The cache unit 62 calculates the difference threshold of the TOF of the object corresponding to the target based on the target threshold information 60 obtained in step S21. The cache unit 62 calculates the difference value diff(i, j, t) of the distance in the past M transmitted wave frames and the minimum TOF min and the threshold value of the difference in TOF of the object corresponding to the target are buffered (step S24). Here, diff(i,j,t)=|TOF i (t)-TOF j (t)|(i≠j).

[0111] Thereafter, the object determination unit 57 calculates the maximum value diff of the distance difference values ​​diff(i, j, t) in the past M transmitted wave frames including the time t. max (t) is calculated (step S25). max (t) = max(diff(i,j,t-(M-1)),···,diff(i,j,t)).

[0112] Then, the object determination unit 57 calculates the maximum value diff max (t) is the threshold value Th of pole 41 pоle It is determined whether the threshold value Th is smaller than the threshold value Th (step S26). pоle is preset.

[0113] Maximum diff max (t) is the threshold value Th of pole 41 pоle If the calculated position coordinates are smaller than the predetermined range (step S26, YES), the object determination unit 57 further calculates the S0 coordinate, the S1 coordinate, the S4 coordinate, and the S5 coordinate using the triangulation method described above (step S33), and determines whether the y-axis (vehicle width direction) of the calculated position coordinates varies beyond a predetermined range (step S34). If the calculated position coordinates do not vary (step S34, NO), the object is determined to be a pole 41 (step S35), and the output unit 58 outputs the determination result (step S30). If the calculated position coordinates vary (step S34, YES), the process proceeds to step S27.

[0114] Maximum diff max (t) is the threshold value Th of pole 41 pоle If the difference is equal to or greater than the predetermined value (NO in step S26), or if the calculated y-axis (vehicle width direction) values ​​of the S0 coordinate, S1 coordinate, S4 coordinate, and S5 coordinate vary beyond a predetermined range, the object determination unit 57 calculates the maximum value diff max (t) is the threshold value Th of curb 31 curb It is determined whether it is smaller than (step S27).

[0115] Maximum diff max (t) is the threshold value Th of curb 31 curbIf it is smaller than (step S27, YES), the object determination unit 57 determines that the object is the curbstone 31 (step S32), and the output unit 58 outputs the determination result (step S30).

[0116] Maximum diff max (t) is the threshold value Th of curb 31 curb If it is equal to or greater than the maximum value diff max (t) is the threshold value Th of pedestrian 21 ped It is determined whether the value is smaller than (step S28).

[0117] Maximum diff max (t) is the threshold value Th of pedestrian 21 ped If it is smaller than (step S28, YES), the object determination unit 57 determines that the object is a pedestrian 21 (step S31), and the output unit 58 outputs the determination result (step S30).

[0118] Maximum diff max (t) is the threshold value Th of pedestrian 21 ped If so (step S28, NO), the object determination unit 57 determines that the object is something other than the pedestrian 21, the curb 31, or the pole 41 (step S29), and the output unit 58 outputs the determination result (step S30).

[0119] In this way, by determining the object based on the maximum value of the difference in distance to the object for the M frames measured and buffered by each sonar device, the determination device 61 can accurately determine the object.

[0120] (Embodiment 3) Fig. 20 is a diagram showing an example of the configuration of a determination device 71 according to embodiment 3. As shown in Fig. 20, the determination device 71 includes a pedestrian determination unit 72 and a transmission wave control output unit 73 in addition to the configuration of the determination device 61 according to embodiment 2.

[0121] The pedestrian determination unit 72 determines whether the object is a pedestrian 21 based on the information on the difference value of the latest TOF. If the object is determined to be a pedestrian 21, the wave transmission control output unit 73 causes the wave transmitting device corresponding to the latest TOF to continuously transmit ultrasonic waves in the next wave transmission cycle.

[0122] Next, a description will be given of the object type determination process performed by the determination device 71. As shown in Fig. 21, first, the object threshold calculation unit 56 of the determination device 71 acquires the sonar mounted information 59 and the object threshold information 60 (step S41).

[0123] The input unit 53 receives the ultrasonic reflection intensity P measured by each sonar device 52 at time t. i (i=1,...,N) and the distance TOF i The input of information (t) (i=1, . . . , N) is accepted (step S42). Here, it is assumed that there are N sonar devices.

[0124] Next, the difference calculation unit 54 calculates the reflection intensity P i It is determined whether or not the threshold value Th1 is greater than the threshold value Th1 and less than the threshold value Th2 (step S43). The threshold values ​​Th1 and Th2 are set in advance.

[0125] Reflection intensity P i If is not within the range of being greater than the threshold value Th1 and smaller than the threshold value Th2 (step S43, NO), the process of step S42 is executed again.

[0126] Reflection intensity P i is greater than the threshold value Th1 and less than the threshold value Th2 (step S43, YES), the difference calculation unit 54 calculates the difference between the TOFs i (t) (i, j = 1,..., N) is calculated, and the shortest distance calculation unit 55 calculates the distance TOF i (t) minimum TOF min and outputs it to the object threshold calculation unit 56. The object threshold calculation unit 56 calculates the minimum value TOF of the input distances. minThe cache unit 62 calculates the difference threshold of the TOF of the object corresponding to the target based on the target threshold information 60 obtained in step S41. The cache unit 62 calculates the difference value diff(i, j, t) of the distance in the past M transmitted wave frames and the minimum TOF min and the threshold value of the difference in TOF of the object corresponding to the target are buffered (step S44). Here, diff(i,j,t)=|TOF i (t)-TOF j (t)|(i≠j).

[0127] Furthermore, the difference calculation unit 54 calculates the maximum value diff of the difference values ​​diff(i,j,t) at time t. max (t, 1), and the object determination unit 57 calculates the maximum value diff(i, j, t) of the distance difference values ​​diff(i, j, t) in the past M transmitted wave frames buffered in the cache unit 62. max (t, M) is calculated (step S45).

[0128] where diff max (t,1)=max(diff(i,j,t))(i,j=1,...,N), diff max (t,M)=max(diff(i,j,t-(M-1)),···,diff(i,j,t))(i,j=1,···,N).

[0129] Then, the pedestrian determination unit 72 calculates the maximum value diff of the difference values ​​diff(i, j, t) at time t. max (t,1) is the threshold value Th of curb 31 curb and the threshold value Th of pedestrian 21 ped It is determined whether the threshold value Th is smaller than the threshold value Th (step S46). curb and threshold Th ped is preset.

[0130] Maximum diff max (t,1) is the threshold value Th of curb 31 curb and the threshold value Th of pedestrian 21 ped If it is smaller than (YES in step S46), it is highly likely that the pedestrian 21 has been detected correctly.

[0131] Therefore, in order to maintain the current good detection state of the pedestrian 21 in the next wave transmission cycle, the wave transmission control unit 73 changes the control signal that controls each sonar device 52, and controls each sonar device 52 so that the sonar device 52 that is currently transmitting waves continues to transmit waves without switching the sonar device 52 that is transmitting waves (step S55).

[0132] After the process of step S55 or in step S46, the maximum value diff max (t,1) is the threshold value Th of curb 31 curb or below the threshold Th of pedestrian 21 ped If it is equal to or greater than the maximum value diff max (t,M) is the threshold value Th pоle It is determined whether the threshold value Th is smaller than the threshold value Th (step S47). pоle is set in advance. In this case, in the next wave transmission period, the sonar device 52 that transmits waves is switched as shown in Fig. 12A.

[0133] Maximum diff max (t,M) is the threshold value Th pоle If the calculated position coordinates are smaller than the predetermined range (step S47, YES), the object determination unit 57 further calculates the S0 coordinate, the S1 coordinate, the S4 coordinate, and the S5 coordinate using the triangulation described above (step S56), and determines whether the y-axis (vehicle width direction) of the calculated position coordinates varies beyond a predetermined range (step S57). If the calculated position coordinates do not vary (step S57, NO), the object is determined to be a pole 41 (step S58), and the output unit 58 outputs the determination result (step S51). If the calculated position coordinates vary (step S57, YES), the process proceeds to step S48.

[0134] Maximum diff max (t,M) is the threshold value Th pоleIf the difference is equal to or greater than the predetermined value (NO in step S47), or if the calculated y-axis (vehicle width direction) values ​​of the S0 coordinate, S1 coordinate, S4 coordinate, and S5 coordinate vary beyond a predetermined range, the object determination unit 57 calculates the maximum value diff max (t,M) is the threshold value Th of curb 31 curb It is determined whether it is smaller than (step S48).

[0135] Maximum diff max (t,M) is the threshold value Th of curb 31 curb If it is smaller than (step S48, YES), the object determination unit 57 determines that the object is the curbstone 31 (step S53), and the output unit 58 outputs the determination result (step S51).

[0136] Maximum diff max (t,M) is the threshold value Th of curb 31 curb If it is equal to or greater than the maximum value diff max (t,M) is the threshold value Th ped It is determined whether it is smaller than (step S49).

[0137] Maximum diff max (t,M) is the threshold value Th ped If it is smaller than (step S49, YES), the object determination unit 57 determines that the object is a pedestrian 21 (step S52), and the output unit 58 outputs the determination result (step S51).

[0138] Maximum diff max (t,M) is the threshold value Th ped If so (step S49, NO), the object determination unit 57 determines that the object is something other than the person 21, the curb 31, or the pole 41 (step S50), and the output unit 58 outputs the determination result (step S51).

[0139] In this way, when there is a high possibility that a pedestrian 21 has been detected, the sonar device 52 that is currently transmitting waves continues to transmit waves in the next transmission cycle, thereby maintaining a good current detection state of the pedestrian 21.

[0140] (Fourth embodiment) In the fourth embodiment, we will explain the case where a pedestrian's walking motion is detected based on the detection distance detected by one or more sonar devices. When a person walks, their hands and feet move, and the reflection points change over time. Therefore, the detection distance changes.

[0141] 22 shows, for example, a case where the sonar device that transmits waves is RRC12 and the sonar device that receives waves is RLC13. In this example, the reflection point of the transmitted ultrasonic waves is the right knee 101 of the pedestrian 21. Also, in FIG. 23, the reflection point has changed, and the reflection point of the transmitted ultrasonic waves is now the head 102 of the pedestrian 21. In this way, as the pedestrian 21 walks, the reflection point of the ultrasonic waves changes from the right knee 101 to the head 102, and, for example, the detection distance becomes longer than in the previous wave transmission frame.

[0142] Similarly, in the case of other combinations of sonar devices, such as when the transmitting sonar device is an RLC13 and the receiving sonar device is an RLC13, when a person walks, their hands and feet move, changing the reflection point over time, and as a result, the detection distance changes.

[0143] Fig. 24 shows an example of data used to determine whether or not an object is a pedestrian. Fig. 24 shows data used to determine whether or not an object is a pedestrian from the detection distance acquired by the RLC 13, for example. This data includes four pieces of information: vehicle speed, wave transmission time, wave transmission device number, and detection distance. The wave transmission device number is the number of the sonar device that transmitted the reflected wave received by the RLC 13.

[0144] To determine whether or not an object is a pedestrian, the difference between the actually measured distance from the sonar device to the pedestrian and the estimated value of the distance from the sonar device to the pedestrian is used. This method is explained below. Figure 25 is a diagram showing a method for calculating the estimated value of the distance from the sonar device to the pedestrian, which is used to determine whether or not an object is a pedestrian. Below, we will explain a method for determining whether or not an object is a pedestrian using the measured distance measured by receiving ultrasonic waves transmitted by the RRC 12 at the RLC 13.

[0145] First, the estimated distance is calculated from the vehicle speed, wave transmission time, and measured distance information for the wave transmitting device number corresponding to 10, which is the number of RRC12. Here, the measured distance information used to calculate the estimated distance is the information at the immediately previous wave transmission time.

[0146] For example, the estimated distance L can be calculated using the formula L i-1 -v × Δt, where L i-1 is the measured distance at the previous wave transmission timing, v is the vehicle speed, and Δt is the elapsed time between the previous wave transmission time and the wave transmission time for which the estimated distance is to be calculated. This estimated distance is the distance between the sonar device and the target object when the target object is assumed to be stationary.

[0147] If the target is stationary, the probability that the reflection point will change for the same combination of sonar device that transmits ultrasonic waves and sonar device that receives them is low, so the difference between the measured distance and the estimated distance will be small. On the other hand, if the target is moving, such as a pedestrian, the probability that the difference between the measured distance and the estimated distance will be large increases. Therefore, by calculating the difference between the measured distance and the estimated distance, it is possible to determine whether the target is moving or not.

[0148] Fig. 26 shows the calculation results of the difference between the measured distance and the estimated distance for a moving object. Fig. 27 shows the calculation results of the difference between the measured distance and the estimated distance for a stationary object. In this experiment, a doll was used as the object.

[0149] As shown in Figure 26, for a moving object, the absolute value of the difference between the measured distance and the estimated distance becomes large. On the other hand, as shown in Figure 27, for a stationary object, the absolute value of the difference between the measured distance and the estimated distance becomes small. Therefore, by setting a threshold and comparing this absolute value with the threshold, it is possible to determine whether or not the object is moving.

[0150] Fig. 28 is a diagram showing an example of the configuration of a determination device 81 according to embodiment 4. As shown in Fig. 28, the determination device 81 has one or more sonar devices 52, a number of cache units 111 corresponding to the number of sonar devices, a number of difference calculation units 54 corresponding to the number of sonar devices, a vehicle movement information acquisition unit 112, a cache unit 62, an object threshold calculation unit 56, an object determination unit 57, and an output unit 58.

[0151] Each sonar device 52 receives ultrasonic waves reflected by an object and outputs information on the reflection intensity corresponding to the TOF. Each sonar device 52 corresponds to the RRC 12, RLC 13, RR 14, and RL 15 described above.

[0152] Each cache unit 111 stores the reflected intensity of ultrasonic waves measured by the sonar device 52 corresponding to the cache unit 111 and the distance to the target, TOF i It accepts input of information (i=1,...,N) and buffers the information.

[0153] Each difference calculation unit 54 obtains information such as the number of sonar devices from sonar installation information 59 stored in the storage unit, obtains the measured distance to the target, vehicle speed information, and wave transmission interval information, and estimates the distance to the target. Each difference calculation unit 54 also calculates the difference between the measured distance at the current time and the estimated distance, and buffers this difference in the cache unit 62.

[0154] The vehicle movement information acquisition unit 112 acquires information such as the vehicle speed and outputs it to the difference calculation unit 54. The cache unit 62 buffers the information on the differences calculated by each difference calculation unit 54.

[0155] The object threshold calculation unit 56 calculates the threshold of the difference calculated by the difference calculation unit 54 based on object threshold information 60 stored in the storage unit. Here, the object threshold information 60 stores information on the threshold of the difference in association with the type of object.

[0156] The object determination unit 57 calculates the maximum value of the past M differences including the time t buffered in the cache unit 62. The object determination unit 57 also compares the value of the difference calculated by the difference calculation unit 54 with the threshold calculated by the object threshold calculation unit 56 to determine the type of object.

[0157] The output unit 58 outputs information on the determination result by the object determination unit 57 to the vehicle's ECU, etc. This information is used to control the collision damage mitigation brake of the vehicle, etc.

[0158] Next, a description will be given of the object type determination process performed by the determination device 81. As shown in Fig. 29, first, the object threshold calculation unit 56 of the determination device 81 acquires the sonar mounted information 59 and the object threshold information 60 (step S61).

[0159] Each cache unit 111 receives the reflected intensity P of the ultrasonic wave measured by the sonar device 52 corresponding to the cache unit 111. i (i=1,...,N) and the distance TOF i The input of information (i=1, . . . , N) is accepted (step S62), and the information is buffered (step S62). Here, it is assumed that there are N sonar devices (N>=1).

[0160] Next, the difference calculation unit 54 calculates the reflection intensity P i It is determined whether or not the threshold value Th1 is greater than the threshold value Th1 and less than the threshold value Th2 (step S63). The threshold values ​​Th1 and Th2 are set in advance.

[0161] Reflection intensity P iIf is not within the range of being greater than the threshold value Th1 and smaller than the threshold value Th2 (step S63, NO), the process of step S62 is executed again.

[0162] Reflection intensity P i is greater than the threshold value Th1 and less than the threshold value Th2 (step S63, YES), the difference calculation unit 54 calculates the measured distance TOF measured at the previous time t-1 from the cache unit 111 corresponding to each sonar device 52. i (t-1), the vehicle movement information acquisition unit 112 acquires information on the vehicle speed v and the sonar device 52 transmits the wave interval Δt (=T i -T i-1 ) information and estimate the distance TOF_est corresponding to each sonar device. i (t) is calculated using the following formula (step S64). TOF_est i (t)=TOF i (t-1)-v×(T i -T i-1 )

[0163] Furthermore, the difference calculation unit 54 calculates the current measurement value TOF i (t) and estimated distance TOF_est i (t) TOF (i, t) is calculated by the following formula and buffered in the cache unit 62 (step S65). diff TOF (i,t)=|TOF i (t)-TOF_est i (t)|

[0164] Thereafter, the object determination unit 57 calculates the past M differences diff TOF Maximum value of (i,t) diff max (t) is calculated (step S66). max (t)=max(diff TOF (i,t-(M-1)),···,diff TOF (i,t)).

[0165] Then, the object determination unit 57 calculates the maximum value diff max (t) is the threshold value Th of pole 41 pоle It is determined whether the threshold value Th is smaller than the threshold value Th (step S67). pоle is preset.

[0166] Maximum diff max (t) is the threshold value Th of pole 41 pоle If it is smaller than (step S67, YES), the object determination unit 57 determines that the object is a pole 41 (step S74), and the output unit 58 outputs the determination result (step S71).

[0167] Maximum diff max (t) is the threshold value Th of pole 41 pоle If it is equal to or greater than the maximum value diff max (t) is the threshold value Th of curb 31 curb It is determined whether it is smaller than (step S68).

[0168] Maximum diff max (t) is the threshold value Th of curb 31 curb If it is smaller than (step S68, YES), the object determination unit 57 determines that the object is the curbstone 31 (step S73), and the output unit 58 outputs the determination result (step S71).

[0169] Maximum diff max (t) is the threshold value Th of curb 31 curb If it is equal to or greater than the maximum value diff max (t) is the threshold value Th of pedestrian 21 ped It is determined whether it is smaller than (step S69).

[0170] Maximum diff max (t) is the threshold value Th of pedestrian 21 pedIf it is smaller than (step S69, YES), the object determination unit 57 determines that the object is a pedestrian 21 (step S72), and the output unit 58 outputs the determination result (step S71).

[0171] Maximum diff max (t) is the threshold value Th of pedestrian 21 ped If so (step S69, NO), the object determination unit 57 determines that the object is something other than the person 21, the curb 31, or the pole 41 (step S70), and the output unit 58 outputs the determination result (step S71).

[0172] In this way, by calculating the difference between the actually measured distance from the sonar device to the pedestrian and the estimated distance from the sonar device to the pedestrian, it is possible to more accurately determine whether or not the pedestrian is a pedestrian.

[0173] Here, we calculated the difference between the actually measured distance from the sonar device to the pedestrian and the estimated distance from the sonar device to the pedestrian, but it is also possible to determine whether or not the pedestrian is a pedestrian using the difference in the flight time of ultrasonic waves corresponding to these distances.

[0174] Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments. For example, the determination devices 51, 61, 71, and 81 may be devices mounted on a vehicle or may be devices installed outside a vehicle.

[0175] Furthermore, in the above embodiment, the object was judged based on the distance corresponding to the time of flight of the ultrasonic waves, but since the distance is the time of flight of the ultrasonic waves multiplied by the speed of the ultrasonic waves, by adjusting the threshold value used to judge the object, a similar judgment can be easily made even if the time of flight is used instead of the distance.

[0176] In the above-described embodiments, each component may be realized by executing a software program suitable for that component, or by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0177] Furthermore, the general or specific aspects of the present disclosure may be realized as an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or as any combination of an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0178] In the above description, the expression "... part" used for each component may be replaced with other expressions such as "... assembly," "... circuit," "... device," "... unit," or "... module." Also, the apparatus may be configured to be executed by a CPU using a program stored in memory.

[0179] In addition, this disclosure also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, or forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the intent of this disclosure. [Industrial Applicability]

[0180] The present disclosure can be used in an object determination device and an object determination method for determining an object. [Explanation of symbols]

[0181] 11 vehicles 12 RRC 13 RLC 14RR 15RL 21 people (pedestrians) 22 reflection points 31 Curb 41 Paul 51 Object determination device 52 Sonar Equipment 53 Input section 54 Difference calculation part 55 Shortest distance calculation unit 56 Object threshold calculation unit 57 Object Determination Unit 58 Output section 59 Sonar equipped information 60 Object Threshold Information 62 Cache section 72 Driver Judgment Unit 73 Wave transmission control output section 111 Cache section 112 Vehicle movement information acquisition unit

Claims

1. a calculation unit that calculates a difference in time of flight of a plurality of ultrasonic waves received by a plurality of sonar devices and reflected by an object, or a difference in distance corresponding to the time of flight; a determination unit that determines the type of the object based on the difference; An object determination device comprising:

2. The object determination device according to claim 1 , wherein the determination unit determines the type based on a maximum value of the difference over a plurality of transmission periods.

3. a control unit for switching a sonar device that transmits the ultrasonic waves at each transmission period among the plurality of sonar devices; The object determination device of claim 1, wherein when the type is determined to be a pedestrian based on the difference, the control unit causes the sonar device that transmitted the ultrasonic waves corresponding to the difference to continue transmitting them in the next transmission cycle.

4. a calculation unit that calculates the difference between the time of flight of an ultrasonic wave reflected by an object and an estimated value of the time of flight when the object is assumed to be a stationary object, or the difference between the distance corresponding to the time of flight and the estimated value of the distance when the object is assumed to be a stationary object; a determination unit that determines the type of the object based on the difference; An object determination device comprising:

5. Calculating the difference in time of flight of the plurality of ultrasonic waves received by the plurality of sonar devices and reflected by the target, or the difference in distance corresponding to the time of flight; determining the type of the object based on the difference; Method for determining the object.

6. The object determination method according to claim 5 , wherein the type is determined based on a maximum value of the difference over a plurality of transmission periods.

7. The object determination method described in claim 6, wherein if the type is determined to be a pedestrian based on the difference, the sonar device that transmitted the ultrasonic waves corresponding to the difference is caused to continue transmitting waves in the next transmission cycle.

8. Calculating the difference between the time of flight of the ultrasonic wave reflected by the object and the estimated value of the time of flight when the object is assumed to be stationary, or the difference between the distance corresponding to the time of flight and the estimated value of the distance when the object is assumed to be stationary, determining the type of the object based on the difference; Method for determining the object.

Images