Method, computer readable medium, radar object detection system, and vehicle identification system - Patents.com

Abstract

To detect the approach of another vehicle of a specific type that travels in the vicinity of a host vehicle.SOLUTION: A method executed by a radar object detection system of a host vehicle comprises the steps of: detecting the first radar reflection point of an object reflecting a radar signal on the outer side of a blind region; setting an object region on the basis of the distribution of a group of the first radar reflection points; estimating that the object is another vehicle on the basis of a positional relation between the object region and the blind region; detecting the second radar reflection point on the inner side of the blind region; and determining that the other vehicle is the target vehicle when the second radar reflection point satisfies a prescribed first condition.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a system for detecting the approach of a target vehicle, and more particularly to a method for detecting the approach of a specific type of moving vehicle using a radar device, a computer-readable medium, a radar object detection system, and a vehicle identification system. [Background technology]

[0002] It is known that a radar device is mounted on a host vehicle and other vehicles present in the vicinity of the host vehicle are detected by the radar device. Patent Document 1 describes a system that distinguishes a trailer towed by the host vehicle from other vehicles present in the vicinity of the host vehicle. This makes it possible to prevent the host vehicle from mistakenly detecting that there is another vehicle in the vicinity of the host vehicle when in fact only a trailer is present. In the system described in Patent Document 1, a radar signal emitted from the radar device is used to detect a signal indicating an object approaching the host vehicle. Based on this signal, it is determined when a trailer is connected to the host vehicle, and further a region blocked by the trailer towed by the host vehicle is defined. This makes it possible to ignore targets detected within this region. However, the technology described in Patent Document 1 does not allow the radar device to detect trailers traveling in the vicinity of the host vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2016 / 0274228 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in consideration of the above-mentioned points, and has as its object to detect the approach of a specific type of other vehicle, such as a trailer, by using an on-vehicle radar device. [Means for solving the problem]

[0005] [Mode 1] According to mode 1, a method executed by a radar object detection system of a host vehicle includes the steps of: detecting a first radar reflection point of an object that reflects a radar signal outside a blind area; setting an object area based on a distribution of a group of the first radar reflection points; and, when the object area is an area formed at a predetermined position with respect to the blind area by another vehicle approaching the host vehicle, estimating that the object is another vehicle, wherein the bottom surface of the other vehicle is within the Radar mounted on the host vehicle the step of detecting a second radar reflection point inside the blind area; and the step of determining that the other vehicle is a target vehicle if a predetermined first condition is satisfied, wherein the predetermined first condition is that a reflected wave from the second radar reflection point has characteristics of a reflected wave from the other vehicle.

[0006] [Mode 2] According to mode 2, a radar object detection system for a host vehicle includes a first detection unit that detects a first radar reflection point of an object that reflects a radar signal outside a blind area, a region setting unit that sets an object area based on a distribution of a group of the first radar reflection points, and a vehicle estimation unit that estimates that the object is another vehicle when the object area is an area formed at a predetermined position with respect to the blind area by another vehicle approaching the host vehicle, and the bottom surface of the other vehicle is located in the blind area. Radar mounted on the host vehicle The present invention provides a radar object detection system including: a vehicle estimation unit that is higher than the device; a second detection unit that detects a second radar reflection point inside the blind area; and a target determination unit that determines that the other vehicle is a target vehicle if a predetermined first condition is satisfied, wherein the predetermined first condition is that a reflected wave from the second radar reflection point has characteristics of a reflected wave from the other vehicle. Effect of the Invention

[0007] According to the present disclosure, an on-board radar device can be used to detect the approach of a specific type of other vehicle, such as a trailer. [Brief description of the drawings]

[0008] [Figure 1] 1 is a top view illustrating a state in which a host vehicle and another vehicle traveling near the host vehicle are traveling in a vehicle lane according to an embodiment of the present disclosure. [Diagram 2] 2 is a side view of the top view shown in FIG. 1 as seen from the left side. [Diagram 3] 1 is a block diagram showing a configuration of an in-vehicle system according to an embodiment of the present disclosure. [Figure 4] 4 is a block diagram showing a functional configuration of a processing unit 300 of the in-vehicle radar device 14 shown in FIG. 3 according to an embodiment of the present disclosure. FIG. [Diagram 5] FIG. 5 illustrates an example of a process performed in an in-vehicle system according to one embodiment of the present disclosure. [Figure 6] FIG. 13 is a diagram illustrating a positional relationship between an object region and a blind region according to an embodiment of the present disclosure. [Figure 7A] 11 is a diagram showing a positional relationship in the front-rear direction between a second radar reflection point and an object area according to an embodiment of the present disclosure. FIG. [Figure 7B] 11 is a diagram showing a positional relationship in the left-right direction between a second radar reflection point and an object area according to an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiment of the present invention] First, the contents of the embodiment of the present invention will be listed and described. One embodiment of the present invention has the following configuration.

[0010] (Item 1) 1. A method performed by a radar object detection system of a host vehicle, comprising: detecting a first radar reflection point of an object reflecting a radar signal outside the blind area; setting an object region based on a distribution of the first group of radar reflection points; estimating that the object is another vehicle based on a positional relationship between the object area and the blind area; detecting a second radar reflection point inside the blind area; determining that the other vehicle is a target vehicle if the second radar reflection point satisfies a predetermined first condition; A method comprising:

[0011] (Item 2) The method according to (Item 1), wherein the blind area is preset based on a position of a radar device mounted on the host vehicle and a traveling direction of the host vehicle.

[0012] (Item 3) The method according to (Item 1) or (Item 2), wherein the height of the bottom surface between the front and rear wheels of the target vehicle is higher than the height of a radar device mounted on the host vehicle.

[0013] (Item 4) A method according to either (Item 1) or (Item 3), wherein an area of ​​the bottom surface of the target vehicle defined based on the front and rear wheels of the target vehicle is larger than the blind area.

[0014] (Item 5) A method according to any one of (item 1) to (item 4), wherein the target vehicle is a trailer.

[0015] (Item 6) A method according to any one of (Item 1) to (Item 5), wherein the positional relationship includes any one of a first positional relationship, a second positional relationship, a third positional relationship, a fourth positional relationship, and a fifth positional relationship; The first positional relationship is defined in a traveling direction of the host vehicle such that the object area is behind the blind area; The second positional relationship is such that the object region is defined in front of the blind region, The third positional relationship is such that the object area is defined on a side of the blind area opposite to the host vehicle, The fourth positional relationship is such that the object area is defined diagonally forward of the blind area on a side opposite to the host vehicle, The method of claim 5, wherein the object area is defined diagonally rearward of the blind area on the opposite side to the host vehicle.

[0016] (Item 7) A method according to any one of (Item 1) to (Item 6), wherein the step of estimating that the object is another vehicle further includes a step of estimating that the object is another vehicle based on a relative speed of the first radar reflection point with respect to a moving speed of the host vehicle.

[0017] (Item 8) A method according to any one of (Item 1) to (Item 7), wherein the step of detecting the second radar reflection point comprises: Identifying a singular point that satisfies a second predetermined condition among reflection points detected inside the blind area; removing the identified singular points from the second radar reflection points; A method comprising:

[0018] (Item 9) The method according to (Item 8), wherein the second predetermined condition is that the electromagnetic wave intensity of the reflected wave from the second radar reflection point is less than a first predetermined threshold.

[0019] (Item 10) The method according to (Item 8) or (Item 9), wherein the second predetermined condition is that the range rate of the reflected wave from the second radar reflection point is approximately zero.

[0020] (Item 11) A method according to any one of (Item 8) to (Item 10), wherein the predetermined second condition is that an index indicating goodness of angular accuracy of the second radar reflection point is the worst.

[0021] (Item 12) The method according to claim 9, wherein the step of detecting the second radar reflection point comprises: detecting, among the second radar reflection points, reflection points that satisfy at least one of the following: an electromagnetic wave intensity of a reflected wave from the second radar reflection point is less than a second predetermined threshold; and a reflected wave from the second radar reflection point does not have a constant range rate, wherein the second predetermined threshold is greater than the first predetermined threshold.

[0022] (Item 13) A method according to any one of (Item 1) to (Item 12), wherein the predetermined first condition includes that a distance between the second radar reflection point and the object area is longer than a specific distance.

[0023] (Item 14) A method as described in (Item 13), wherein the specific distance is lt / 2 in the longitudinal direction or wt / 2 in the transverse direction with respect to the direction of travel of the host vehicle, where lt is the longitudinal length of the object area and wt is the transverse length of the object area.

[0024] (Item 15) A computer-readable medium storing a program for causing a radar object detection system to execute the method according to any one of (item 1) to (item 14).

[0025] (Item 16) 1. A radar object detection system for a host vehicle, comprising: a first detector for detecting a first radar reflection point of an object that reflects a radar signal outside the blind area; a region setting unit that sets an object region based on a distribution of the first radar reflection point group; a vehicle estimation unit that estimates that the object is another vehicle based on a positional relationship between the object area and the blind area; a second detector configured to detect a second radar reflection point inside the blind area; a target determination unit that determines that the other vehicle is a target vehicle when the second radar reflection point satisfies a predetermined first condition; 1. A radar object detection system comprising:

[0026] (Item 17) A radar object detection system according to claim 16, wherein the blind area is preset based on the position of the radar device and the traveling direction of the host vehicle.

[0027] (Item 18) A vehicle identification system comprising: a radar object detection system according to (Item 16) or (Item 17); and a driving assistance device configured to receive a signal from the radar object detection system and notify a driver of the host vehicle equipped with a radar device that the object is the target vehicle based on the signal.

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a top view illustrating a state in which a vehicle 10 equipped with an on-vehicle system 100 according to an embodiment of the present disclosure and another vehicle 20 traveling near the vehicle 10 are traveling in a vehicle lane. The on-vehicle system 100 shown in Fig. 1 detects an object around the vehicle 10 by an on-vehicle radar device 14, estimates the detected object as the other vehicle 20, and determines that the other vehicle 20 is a specific type of vehicle.

[0029] FIG. 1 is a top view of a vehicle 10 traveling in a lane L1 and another vehicle 20 traveling in a lane L2 adjacent to the lane L1. A blind area 6R exists on the right rear side of the vehicle 10, and a blind area 6L exists on the left rear side. The blind areas 6R and 6L are set in advance for each vehicle 10 based on the position of the on-board radar device 14 arranged on the vehicle 10 and the traveling direction of the vehicle 10. The blind areas 6R and 6L are areas that are blind spots of the vehicle 10, and are areas used for the purpose of a so-called BSW (Blind Spot Warning) function that issues an alarm when another vehicle 20 is in this zone. The blind areas 6L and 6R are not limited to the rectangular shape and size exemplified in FIG. 1, and may be of any shape and size.

[0030] (Vehicle configuration) 1, a vehicle 10 includes at least a vehicle body 12 and an on-vehicle radar device 14 (on-vehicle radar device 14R and on-vehicle radar device 14L) which is a radar device mounted on the vehicle body 12. The vehicle 10 is a moving body, for example, a four-wheeled ordinary automobile, but is not limited thereto, and may be, for example, a small truck having six or more wheels, a two-wheeled automobile, etc. For convenience of explanation, the directional concepts of "front", "rear", "left", and "right" in the vehicle 10 are defined as shown by arrows in the figure. Such directional concepts are based on the driver of the vehicle 10 traveling forward.

[0031] 1, the on-vehicle radar device 14R is mounted near the right rear corner of the vehicle body 12, and the on-vehicle radar device 14L is mounted near the left rear corner of the vehicle body 12. In the following, when there is no need to distinguish between the on-vehicle radar device 14L and the on-vehicle radar device 14R, they will be simply referred to as "on-vehicle radar device 14." In addition, in the following, the vehicle 10 on which the on-vehicle radar device 14 is mounted will be referred to as a host vehicle.

[0032] The on-vehicle radar device 14 is mounted on the host vehicle 10 and configured to detect an object that has a high possibility of colliding with the host vehicle 10 by transmitting and receiving electromagnetic waves. Specifically, the on-vehicle radar device 14 transmits a radar signal, which is an electromagnetic wave, and receives the reflected wave of the radar signal reflected by the object, thereby being able to measure the distance to the object from the time lag between the transmitted radar signal and the radar signal reflected by the object. The on-vehicle radar device 14 is a millimeter wave radar, a microwave radar, or the like.

[0033] The on-vehicle radar device 14 is disposed so that the propagation area 18 of the radar signal is an angle range (approximately -70° to +70° in the illustrated example) centered on a substantially lateral direction of the host vehicle 10 (a direction of approximately ±120° when the straight-ahead direction is 0° in the illustrated example). The on-vehicle radar device 14 emits a radar signal into the propagation area 18, and can detect the position and relative speed of a reflection point within the propagation area 18 based on a received signal from a reflection point that reflects the radar signal. Hereinafter, when there is no need to distinguish between the right-side propagation area 18R and the left-side propagation area 18L, they will simply be referred to as "propagation area 18".

[0034] The vehicle-mounted radar device 14 also detects objects present in a propagation region 18 within a set angle range so as to receive reflected waves emitted from the radar in the horizontal direction. At this time, a radar signal having an angle in the height direction that is off the horizontal direction is also emitted, and when it is reflected, the vehicle-mounted radar device 14 receives the radar signal arriving from the height direction. Reflection points detected from radar signals having such angles in the height direction may appear and disappear intermittently.

[0035] The host vehicle 10 may be equipped with a driving assistance ECU (Electronic Control Unit) 16 (not shown) that is a driving assistance device for the driver. The driving assistance ECU 16 is communicably connected to the on-board radar device 14 and configured to transmit and receive signals to and from the on-board radar device 14. The driving assistance ECU 16 is provided to control driving assistance operations such as collision avoidance based on the detection result by the on-board radar device 14. The driving assistance ECU 16 is provided with a rear side blind spot warning (BSW) that detects another vehicle 20 running parallel to the rear side when it is in a position that is a blind spot and notifies the driver. As an example, the driving assistance ECU 16 is configured to notify the driver of the host vehicle 10 that an object in the vicinity of the host vehicle 10 is a specific type of other vehicle 20 based on a signal received from the on-board radar device 14. The function of determining that the other vehicle 20 traveling alongside the host vehicle 10 is a specific type of other vehicle (hereinafter referred to as a target vehicle) may be provided by the on-board radar device 14 itself as a radar object detection system of the host vehicle 10. In the following, it is assumed that the on-board radar device 14 itself has this function.

[0036] FIG. 2 is a side view of the top view shown in FIG. 1 as seen from the left side. For convenience of explanation, the directional concepts of "up," "down," "front," and "rear" in the host vehicle 10 are defined as indicated by arrows in the figure. The up-down direction may also be referred to as the "vehicle height direction." FIGS. 1 and 2 show an example in which the other vehicle 20 is a target vehicle 26. As shown in FIG. 2, the target vehicle 26 has a bottom surface (bottom surface 24 of the loading platform in the illustrated example) of the vehicle body 12 defined by the front wheels 28 and rear wheels 29 that is higher than the height of the on-board radar device 14 of the host vehicle 10 in the vehicle height direction. Also, the target vehicle 26 has a front wheel 28 and a rear wheel 29 that are spaced apart, and the area of ​​the bottom surface 24 defined by the front wheel 28 and the rear wheel 29 is larger than the blind area 6. Furthermore, the target vehicle 26 has no obstacle (such as a steel plate) between the front wheels 28 and the rear wheels 29 on the height plane (zero plane 22 shown in FIG. 2) on which the on-board radar device 14 is mounted. The target vehicle 26 is, for example, a large automobile such as a trailer or a carrier car.

[0037] Fig. 3 is a block diagram showing an example of the configuration of the on-vehicle system 100 shown in Fig. 1. The on-vehicle system 100 includes an on-vehicle radar device 14 (Fig. 1) and a driving assistance ECU 16. The on-vehicle system 100 is mounted on a host vehicle 10 that also includes the on-vehicle radar device 14.

[0038] The on-board radar system 14 determines whether an object approaching the host vehicle 10 is a particular type of target vehicle 26 that is of interest for detection purposes in accordance with the present disclosure.

[0039] The on-vehicle radar device 14 includes at least a transmitting antenna 302 that emits a radar signal, a distributor 304 that distributes power of a high-frequency signal input from a transmitting circuit 306, a transmitting circuit 306 that supplies a transmission signal to the transmitting antenna 302, a receiving antenna 308 that receives a reflected wave that is a reflected radar signal, a receiving circuit 316 that processes the received signal input from the antenna element to generate a beat signal, a processing unit 300 that executes object detection processing, and an output unit 318 that outputs a signal indicating the presence of an approaching object that is the target vehicle 26 to the driving assistance ECU 16. The on-vehicle radar device 14 shown in FIG. 3 does not include components of a typical radar, such as an amplifier and a filter. The configuration of the on-vehicle radar device 14 shown in FIG. 3 is an example, and there may be multiple transmitting antennas 302 and multiple receiving antennas 308.

[0040] The processing unit 300 includes, as hardware elements, at least a processor 312 and a memory such as a random access memory (RAM) or a read only memory (ROM) (hereinafter, memory 314). The processor 312 is configured to read a program stored in the memory 314 and execute processing in accordance with the program.

[0041] The driving assistance ECU 16 executes various processes for assisting the driver in driving the host vehicle 10 based on various information input from the on-board radar device 14, for example, a signal indicating the approach of the target vehicle 26. The driving assistance processes include, for example, a process for issuing an alarm to the driver that the target vehicle 26 is approaching.

[0042] The driving assistance ECU 16 includes, as hardware elements, at least a processor 162 and a memory 164. The processor 162 is configured to read out a program stored in the memory 164 and execute processing in accordance with the program.

[0043] 4 is a block diagram showing a functional configuration of the processing unit 300 of the on-vehicle radar device 14 shown in FIG. 3 according to an embodiment of the present disclosure. The processing unit 300 has a control unit 410 and a storage unit 430. The control unit 410 includes a first detection unit 412, a region setting unit 414, a vehicle estimation unit 416, a second detection unit 418, and a target determination unit 420. The storage unit 430 corresponds to the memory 314 shown in FIG. 3. The control unit 410 and each unit 412 to 420 included in the control unit 410 represent the function of processing realized by the processor 312 shown in FIG. 3 reading and executing a program in the memory 314.

[0044] The first detector 412 detects a reflection point that reflects a radar signal, and detects the position of the reflection point and the relative speed of the reflection point with respect to the host vehicle 10 .

[0045] The region setting unit 414 sets an object region 602 indicating the presence of an object based on the position distribution of the detected first radar reflection points. The first radar reflection points are reflection points detected outside the blind region 6 (FIG. 1).

[0046] The vehicle estimation unit 416 estimates that the object is another vehicle 20 based on the positional relationship of the object area 602 with respect to the blind area 6 and the like.

[0047] The second detector 418 detects a second radar reflection point inside the blind area 6. The second radar reflection point is a reflection point detected inside the blind area 6 (FIG. 1).

[0048] The target determination unit 420 determines that the other vehicle 20 is a target vehicle 26 when the second radar reflection point satisfies a predetermined condition.

[0049] 5 illustrates an example of a process 500 executed in the in-vehicle system 100 according to an embodiment of the present disclosure. The process 500 illustrates an example of a process flow in which the control unit 410 estimates that an object approaching the vehicle 10 is another vehicle 20 based on reflection point information acquired from the in-vehicle radar device 14, and further determines whether the other vehicle 20 is a target vehicle 26.

[0050] In step S2, the first detection unit 412 emits a radar signal for each preset measurement cycle to the propagation region 18 that is a predetermined angular range of the on-vehicle radar device 14. The first detection unit 412 also detects the position of each reflection point and the relative speed of each reflection point based on the received signal of the reflected wave from the object that reflected the radar signal.

[0051] Next, in step S4, the region setting unit 414 sets one or more object regions 602 based on the distribution of the groups of reflection points outside the blind region 6. As an example, the region setting unit 414 sets the object region 602 indicating the presence of an object at a position where a plurality of reflection points are concentrated. When a plurality of reflection point groups are distributed apart, the object region 602 may be set for each reflection point group.

[0052] Next, in step S6, the vehicle estimation unit 416 determines whether the object region 602 is in a specific positional relationship with respect to the blind region 6. If the object region 602 is in a specific positional relationship with respect to the blind region 6, the process proceeds to step S8. In one example, in step S6, the vehicle estimation unit 416 determines whether the positional relationship of the object region 602 with respect to the blind region 6 is any one of the first positional relationship to the fifth positional relationship shown in Fig. 6. On the other hand, if the object region 602 is not in a specific positional relationship with respect to the blind region 6, the process proceeds to step S18.

[0053] In step S18, the target determination unit 420 performs processing to not set a target flag indicating the presence of a target vehicle 26 approaching the host vehicle 10, and ends the processing.

[0054] FIG. 6 illustrates the positional relationship between the object area 602 and the blind area 6R in relation to step S6. When the traveling direction of the host vehicle 10 is set to be in front of the driver, in the first positional relationship, the object area 602 is defined behind the blind area 6R of the host vehicle 10. In the second positional relationship, the object area 602 is defined in front of the blind area 6R of the host vehicle 10. In the third positional relationship, the object area 602 is defined on the opposite side of the blind area 6R from the host vehicle 10 and to the side of the blind area 6R. In the fourth positional relationship, the object area 602 is defined on the opposite side of the blind area 6R from the host vehicle 10 and diagonally forward of the blind area 6R. In the fifth positional relationship, the object area 602 is defined on the opposite side of the blind area 6R from the host vehicle 10 and diagonally rearward of the blind area 6R. In FIG. 6, the object region 602 is defined as a rectangle, but may be another shape depending on the extent of the distribution of the group of reflection points.

[0055] In the first positional relationship, for example, when the other vehicle 20 is the target vehicle 26, the rear wheel 29 (the left rear wheel in FIG. 6) of the target vehicle 26 on the host vehicle 10 side is set as the object area 602.

[0056] In the second positional relationship, for example, when the other vehicle 20 is the target vehicle 26, the front wheel 28 of the target vehicle 26 on the host vehicle 10 side (the left front wheel in FIG. 6) is set as the object area 602.

[0057] In the third positional relationship, for example, when the other vehicle 20 is the target vehicle 26, the wheel of the target vehicle 26 farther from the host vehicle 10 (the right front wheel or the right rear wheel in FIG. 6) is set as the object area 602.

[0058] In the fourth positional relationship, for example, when the other vehicle 20 is the target vehicle 26, the front wheel 28 (the right front wheel in FIG. 6) of the target vehicle 26 that is farther from the host vehicle 10 is set as the object area 602.

[0059] In the fifth positional relationship, for example, when the other vehicle 20 is the target vehicle 26, the rear wheel 29 (the right rear wheel in FIG. 6) of the target vehicle 26 that is farther from the host vehicle 10 is set as the object area 602.

[0060] Returning to Fig. 5, in step S8, the vehicle estimation unit 416 estimates that the object corresponding to the first radar reflection point that reflects the radar signal is another vehicle 20 approaching the host vehicle 10. If a space without any obstruction, for example the space between the front wheels 28 and the rear wheels 29 of the other vehicle 20, overlaps with the blind area 6, there is no reflection point that reflects the radar signal in this space, and therefore no reflected wave is generated, and the object area 602 is not set within the blind area 6. Even in such a case, in step S8, if the positional relationship between the object area 602 and the blind area 6 is specific, the object is estimated to be another vehicle 20.

[0061] If a plurality of object regions 602 are set, in step S6, the vehicle estimation unit 416 determines which of the first to fifth positional relations each object region 602 falls into. If a plurality of object regions 602 are set, the first to fifth positional relations may occur in a composite manner. In this case as well, in step S8, the vehicle estimation unit 416 estimates that the object corresponding to the first radar reflection point that reflects the radar signal is another vehicle 20 approaching the host vehicle 10.

[0062] In another aspect, in step S6, the vehicle estimation unit 416 may determine whether the positional relationship of the object region 602 with respect to the blind region 6 is any two or more of the first to fifth positional relationships, for example, the first positional relationship, the third positional relationship, and the fifth positional relationship. If all of the first positional relationship, the third positional relationship, and the fifth positional relationship are satisfied, the process proceeds to step S8. On the other hand, if all of the first positional relationship, the third positional relationship, and the fifth positional relationship are not satisfied, in step S8, the vehicle estimation unit 416 determines that the object is not another vehicle 20 approaching the host vehicle 10, and proceeds to step S18.

[0063] Alternatively, in a further embodiment, in step S6, the vehicle estimation unit 416 may determine the positional relationship of the object region 602 with respect to the blind region 6 in a stepwise manner. The vehicle estimation unit 416 may first determine whether or not the object region 602 is in the first positional relationship, and if the object region 602 is not in the first positional relationship, may further determine whether the object region 602 is in any of the third and fifth positional relationships. If the object region 602 is not in any of the first, third and fifth positional relationships, in step S8, the vehicle estimation unit 416 determines that the object is not another vehicle 20, and the process proceeds to step S18. On the other hand, if the object region 602 is in any of the first, third and fifth positional relationships, the process proceeds to step S8.

[0064] Alternatively, in a further aspect, in step S6, the vehicle estimation unit 416 may further determine whether the relative speed of the first radar reflection point detected in step S2 with respect to the moving speed of the host vehicle 10 is within a threshold value. If the relative speed of the first radar reflection point with respect to the moving speed of the host vehicle 10 is within the threshold value, the process proceeds to step S8, and the object corresponding to the first radar reflection point that reflects the radar signal is estimated to be the other vehicle 20 approaching the host vehicle 10. In this way, the vehicle estimation unit 416 can estimate that the object traveling at approximately the same speed as the host vehicle 10 on the side of the host vehicle 10 is the other vehicle 20. On the other hand, if it is determined in step S6 that the relative speed of the first radar reflection point is greater than the threshold value on the host vehicle side, the process proceeds to step S18.

[0065] 5, in step S10, the second detection unit 418 detects a second radar reflection point inside the blind area 6. If a second radar reflection point is detected inside the blind area 6, the process proceeds to step S12. On the other hand, if a second radar reflection point is not detected inside the blind area 6, the process proceeds to step S18.

[0066] The second radar reflection point may be a reflection point caused by the target vehicle 26, or may be a reflection point (hereinafter referred to as a singular point) that is detected even if the target vehicle 26 does not actually exist in the blind area 6. Therefore, in step S10, the second detection unit 418 may further remove the identified singular point from the group of second radar reflection points when there is a singular point that satisfies a predetermined condition from the group of second radar reflection points. In this way, the singular point is removed from the group of second radar reflection points detected inside the blind area 6, and when the target vehicle 26 does not actually exist in the blind area 6, a target flag is not set.

[0067] The singular point is a second radar reflection point that is detected in the blind area 6 even though the target vehicle 26 is not actually present in the blind area 6. When the target vehicle 26 is not present in the blind area 6, there is no reflection point in the blind area 6, and the reflected wave cannot be detected. In this situation, if the second radar reflection point is detected to be present in the blind area 6, it means that the on-board radar device 14 has erroneously detected the second radar reflection point in the blind area 6. The erroneous detection of the second radar reflection point occurs, for example, due to an unwanted reflected wave from a guardrail or the like that is present in the vicinity of the host vehicle 10.

[0068] On the other hand, even when the target vehicle 26 actually exists in the blind area 6, the second detection unit 418 detects the second radar reflection point. Such a second radar reflection point may be caused by the bottom surface 24 between the front wheels 28 and the rear wheels 29 of the target vehicle 26. The height of the bottom surface 24 of the target vehicle 26 is higher than the position of the vehicle-mounted radar device 14. Therefore, when the bottom surface 24 of the target vehicle 26 running parallel to the host vehicle 10 is within the blind area 6, the radar signal traveling from the vehicle-mounted radar device 14 toward the bottom surface 24 has an elevation angle φ ( FIG. 2 ) with respect to the horizontal direction in which the vehicle-mounted radar device 14 is mounted. The elevation angle φ refers to the angle formed by the horizontal plane at the height at which the vehicle-mounted radar device 14 is mounted and a line connecting the vehicle-mounted radar device 14 and the bottom surface 24 (the end portion of the vehicle-mounted radar device 14 closer to the host vehicle 10). That is, the elevation angle φ is determined by the height of the on-board radar device 14, the height of the bottom surface 24 of the target vehicle 26, and a vector from the on-board radar device 14 to the bottom surface 24 of the target vehicle 26 (the end of the bottom surface 24 closer to the host vehicle 10). A reflected wave arriving from the bottom surface 24 and having an elevation angle φ may be detected intermittently. A reflection point (second radar reflection point) detected from such a reflected wave may appear and disappear and be detected intermittently.

[0069] Table 1 summarizes the characteristics of the reflected waves actually measured from the second radar reflection point. The left side of Table 1 shows the characteristics of the reflected waves from the bottom surface 24 of the target vehicle 26 when the object area 602 is in the specific positional relationship with the blind area 6 shown in Figure 6 and the target vehicle 26 running parallel to the host vehicle 10 is present in the blind area 6. The right side of Table 1 shows the characteristics of the reflected waves caused by something other than the target vehicle 26 when the target vehicle 26 is not present in the blind area 6.

[0070] [Table 1]

[0071] Table 1 shows the electromagnetic wave intensity, range rate, and angular accuracy index of the reflected wave from the second radar reflection point. As shown in Table 1, there are differences in the electromagnetic wave intensity, range rate, and angular accuracy index between the reflected wave from the target vehicle 26 and the reflected wave obtained when the target vehicle 26 is not present in the blind area 6.

[0072] The range rate indicates the relative speed of the reflection point with respect to the speed of the host vehicle 10. When the angle of incidence of the reflected wave is constant (e.g., 90°) with the straight-ahead direction of the host vehicle 10 as the reference (0°), the relative speed with respect to the host vehicle 10 is 0, and the range rate is approximately zero. For this reason, the range rate of the unnecessary reflected wave from a guardrail or the like is approximately zero. On the other hand, the range rate of the reflected wave from the target vehicle 26 is not a constant value, but changes over time. This is because when the relative speed of the target vehicle 26 with respect to the host vehicle 10 changes while traveling, the position of the reflection point of the target vehicle 26 (front-rear direction, vehicle height direction) also changes, and the relative speed of the reflection point with respect to the host vehicle 10 changes accordingly.

[0073] Furthermore, the index related to the angular accuracy is an index indicating the quality of the angular accuracy of the reflection point detected by the on-board radar device 14, and is indicated by a plurality of levels. In this embodiment, the index of angular accuracy has four levels from 0 to 3, with 0 indicating the best angular accuracy index and 3 indicating the worst angular accuracy index. When the detected object is the target vehicle 26, the index of angular accuracy is from 0 to 3, and when the detected object is a guardrail or the like other than the target vehicle 26, the index of angular accuracy is 3.

[0074] The angle of the reflected wave from the reflection point can be detected by detecting the phase difference of the reflected wave between each receiving antenna 308 using multiple receiving antennas 308 (FIG. 3) for one transmitting antenna 302 (FIG. 3). For example, when a receiving antenna 308(1) and another receiving antenna 308(2) located at a distance are used, a difference occurs in the distance that the reflected wave from the reflection point reaches these receiving antennas 308(1) and 308(2). From this difference in distance, the phase difference between the signals (reflected waves) received by each receiving antenna can be calculated, and the incident angle of the received signal can be detected from this phase difference. The incident angle is the azimuth angle of the reflection point with respect to the vehicle-mounted radar device 14. The phase difference between the received signals between each receiving antenna is ideally determined by the distance between the receiving antennas and the wavelength of the reflected wave. However, if the signal strength of the received signal is weak or if a strong signal is present in the vicinity of the reflected wave, the phase difference between each receiving antenna varies due to the effect of mutual interference. The greater the variation in phase difference between the receiving antennas, the worse the index of angular accuracy, and the smaller the variation, the better the index of angular accuracy. The variation in phase difference is divided into multiple levels, and an index of angular accuracy is assigned to each level of the variation in phase difference.

[0075] Returning to FIG. 5, as described above, in step S10, the second detection unit 418 identifies a singular point that satisfies a predetermined condition from the group of second radar reflection points, and removes the identified singular point from the group of second radar reflection points. Here, as shown in the right of Table 1, the predetermined condition includes at least one of the following: the electromagnetic wave intensity of the reflected wave corresponding to the second radar reflection point is less than a first predetermined threshold (e.g., less than -7 dBSM), the range rate of the reflected wave is approximately zero, and the angle accuracy index is 3. For example, two or more of the electromagnetic wave intensity, the range rate, and the angle accuracy index may be combined to remove reflection points related to reflected waves reflected from vehicles other than the target vehicle 26. By combining a plurality of conditions, it is possible to identify singular points more accurately.

[0076] In step S10, the second detection unit 418 may further identify, among the second radar reflection points, a second radar reflection point corresponding to the characteristics of the reflected wave reflected from the target vehicle 26. That is, in step S10, the second detection unit 418 may identify, among the second radar reflection points, a reflection point having the characteristics of the reflected wave reflected from the target vehicle 26 using the electromagnetic wave intensity and range rate of the reflected wave. In one example, as shown in the left side of Table 1, the second detection unit 418 detects a second radar reflection point corresponding to a reflected wave that satisfies at least one of the following: the electromagnetic wave intensity of the reflected wave related to the second radar reflection point is less than a second predetermined threshold (e.g., less than 2 dBSM) and the range rate does not have a constant value. The second predetermined threshold is greater than the first predetermined threshold. Furthermore, in step S10, the second detection unit 418 may identify, among the second radar reflection points, a reflection point based on a reflected wave that is intermittently detected. By identifying and extracting reflection points having characteristics of the reflected wave from the target vehicle 26 from among the second radar reflection points, the target vehicle 26 can be identified more accurately.

[0077] Next, in step S12, if the second radar reflection point satisfies the predetermined condition, the target determination unit 420 proceeds to step S14, or if the second radar reflection point does not satisfy the predetermined condition, the target determination unit 420 proceeds to step S18.

[0078] The predetermined condition in step S12 is that the distance between the second radar reflection point and the center of the object region 602 when the object region 602 is a rectangle is longer than a specific distance. If the distance between the second radar reflection point and the center of the object region 602 is longer than the specific distance, the process proceeds to step S14. On the other hand, if the predetermined condition is not satisfied in step S12, the process proceeds to step S18.

[0079] However, when the other vehicle 20 is the target vehicle 26, the second radar reflection point detected at the same position as the first radar reflection point is likely to be a false detection. If the object area 602 determined based on the first radar reflection point (reflection point due to the wheels of the other vehicle 20) and the second radar reflection point (reflection point due to the bottom surface 24) close to the first radar reflection point are determined to be caused by the same target vehicle 26, it is recognized that there is no difference in the height direction between the wheels and the bottom surface 24. Therefore, when the other vehicle 20 is the target vehicle 26, the object area 602 set based on the position of the first radar reflection point (reflection point due to the wheels) that reflects the radar signal emitted in the approximately horizontal direction and the second radar reflection point (reflection point due to the bottom surface 24) that reflects the radar signal emitted in the height direction should be far away. In the present disclosure, the second radar reflection point close to the object area 602 is excluded.

[0080] Figures 7A and 7B show the positional relationship between a plurality of second radar reflection points inside the blind area 6 and the object area 602. Figure 7A shows the positional relationship between the second radar reflection points and the object area 602 in the front-rear direction (longitudinal direction in Figure 7A). Figure 7B shows the positional relationship between the second radar reflection points and the object area 602 in the left-right direction (shortitudinal direction in Figure 7A).

[0081] In FIG. 7A, the second radar reflection point 702 is inside the blind area 6 and inside the object area 602. The second radar reflection point 704 is inside the blind area 6 and is farther away from the object area 602 than a specific distance. lt is the length of the object area 602 in the front-rear direction, that is, the length from the front end to the rear end of the object area 602, and lx is the length in the front-rear direction from one reflection point to the center of the object area 602.

[0082] In FIG. 7B, the second radar reflection point 706 is inside the blind area 6 and inside the object area 602. The second radar reflection point 708 is inside the blind area 6 and is farther away from the object area 602 than a specific distance. wt is the length of the object area 602 in the left-right direction, that is, the length from the left end to the right end of the object area 602, and ly is the length in the left-right direction from one reflection point to the center of the object area 602.

[0083] Returning to FIG. 5, in step S12, when it is determined that the distance between the second radar reflection point and the object area 602 is longer than a specific distance, the process proceeds to step S14. The specific distance is, for example, lt / 2 or wt / 2. When the specific distance is lt / 2 and wt / 2, when the relationship between the distance from the second radar reflection point to the center of the object area 602 satisfies at least one of |lx|>lt / 2 or |ly|>Wt / 2, the process proceeds to step S14.

[0084] Note that the specific distances lt / 2 and wt / 2 are examples and are not limited thereto. For example, when the relationship between the distance from the second radar reflection point to the center of the object area 602 satisfies at least one of |lx| / (lt / 2)>1 + n / 100 or |ly| / (Wt / 2)>1 + n / 100 (0 < n < 100), the process may proceed to step S14.

[0085] Next, in step S14, the target determination unit 420 determines that the other vehicle 20 associated with the second radar reflection point is the target vehicle 26, and proceeds to step S16. On the other hand, if it is determined in step S12 that the distance between the second radar reflection point and the object region 602 is equal to or shorter than the specific distance, the process proceeds to step S18.

[0086] In step S16, the target determination unit 420 sets a target flag indicating that the detected object is the target vehicle 26. Furthermore, the target determination unit 420 transmits the target flag to the driving assistance ECU 16. Furthermore, in step S16, upon receiving the target flag, the driving assistance ECU 16 may issue an alarm notifying the driver of the presence of the target vehicle 26 traveling parallel to the side of the host vehicle 10.

[0087] According to the present disclosure, even if the target vehicle 26 is traveling near the host vehicle 10 and the radar signal transmitted by the on-board radar device 14 is emitted to the zero plane 22 in the space between the front wheels 28 and rear wheels 29 of the target vehicle 26 and is not reflected, the presence of the target vehicle 26 can be detected based on information from the on-board radar device 14.

[0088] Although the embodiment of the present invention has been described above, the above-mentioned embodiment of the invention is intended to facilitate understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. In addition, any combination of the embodiments and modifications is possible within the scope of solving at least a part of the above-mentioned problems or achieving at least a part of the effects, and any combination or omission of each component described in the claims and specification is possible. [Explanation of symbols]

[0089] 6…Blind area 10…Host vehicle 12…Body 14...Automotive radar device 18…Propagation region 20…Other vehicles 22...Zero plane 24…Bottom 26…Target vehicle 100…In-vehicle systems 300... Processing unit

Claims

1. 1. A method performed by a radar object detection system of a host vehicle, comprising: detecting a first radar reflection point of an object reflecting a radar signal outside the blind region; setting an object region based on a distribution of the first group of radar reflection points; A step of estimating that the object is another vehicle when the object area is an area formed at a predetermined position with respect to the blind area by another vehicle approaching the host vehicle, the bottom surface of the other vehicle being higher than a radar device mounted on the host vehicle; detecting a second radar reflection point inside the blind area; a step of determining that the other vehicle is a target vehicle when a predetermined first condition is satisfied, the predetermined first condition being that a reflected wave from the second radar reflection point has characteristics of a reflected wave from the other vehicle; A method comprising:

2. 2. The method of claim 1 , The method, wherein the blind area is preset based on a position of a radar device mounted on the host vehicle and a traveling direction of the host vehicle.

3. 3. The method according to claim 1 or 2, wherein the height of the bottom surface between the front and rear wheels of the target vehicle is higher than the height of a radar device mounted on the host vehicle.

4. The method according to claim 1 , wherein an area of ​​the underside of the target vehicle defined based on the front and rear wheels of the target vehicle is larger than the blind area.

5. The method of any one of claims 1 to 4, wherein the target vehicle is a trailer.

6. 6. The method according to claim 1, wherein a positional relationship between the object region and the blind region includes any one of a first positional relationship, a second positional relationship, a third positional relationship, a fourth positional relationship, and a fifth positional relationship; the first positional relationship is defined with respect to a traveling direction of the host vehicle, the object area being behind the blind area; The second positional relationship is such that the object region is defined in front of the blind region, The third positional relationship is such that the object area is defined on a side of the blind area opposite to the host vehicle, The fourth positional relationship is such that the object area is defined diagonally forward of the blind area on a side opposite to the host vehicle, The method of claim 5, wherein the object area is defined diagonally rearward of the blind area on an opposite side to the host vehicle.

7. 7. A method according to any one of claims 1 to 6, wherein the step of estimating that the object is another vehicle further includes a step of estimating that the object is another vehicle based on a relative speed of the first radar reflection point with respect to a moving speed of the host vehicle.

8. 8. The method according to claim 1, wherein the step of detecting the second radar reflection point comprises: Identifying a singular point that satisfies a second predetermined condition among reflection points detected inside the blind area; removing the identified singular points from the second radar reflection points; and wherein the predetermined second condition is that the point has characteristics that are not reflection points caused by the other vehicle.

9. 9. The method of claim 8, wherein the second predetermined condition is that the electromagnetic wave strength of the reflected wave from the second radar reflection point is less than a first predetermined threshold.

10. 10. The method according to claim 8 or 9, wherein the second predetermined condition is that the range rate of the reflected wave from the second radar reflection point is approximately zero.

11. The method according to claim 8 , wherein the second predetermined condition is that an index indicating goodness of angular accuracy of the second radar reflection point is the worst.

12. 10. The method of claim 9, wherein the step of detecting the second radar reflection point comprises: detecting, among the second radar reflection points, reflection points that satisfy at least one of the following: an electromagnetic wave intensity of a reflected wave from the second radar reflection point is less than a second predetermined threshold; and a reflected wave from the second radar reflection point does not have a constant range rate, wherein the second predetermined threshold is greater than the first predetermined threshold.

13. 13. A method according to any one of claims 1 to 12, wherein the predetermined first condition includes a distance between the second radar reflection point and the object area being longer than a specific distance, the specific distance being lt / 2 in the longitudinal direction or wt / 2 in the lateral direction with respect to the direction of travel of the host vehicle, lt being the longitudinal length of the object area and wt being the lateral length of the object area.

14. A computer readable medium storing a program for causing a radar object detection system to perform the method of any one of claims 1 to 13.

15. 1. A radar object detection system for a host vehicle, comprising: a first detector for detecting a first radar reflection point of an object that reflects a radar signal outside the blind area; a region setting unit that sets an object region based on a distribution of the group of the first radar reflection points; a vehicle estimation unit that estimates that the object is another vehicle when the object area is an area formed at a predetermined position with respect to the blind area by another vehicle approaching the host vehicle, the bottom surface of the other vehicle being higher than a radar device mounted on the host vehicle; a second detector configured to detect a second radar reflection point inside the blind area; a target determination unit that determines that the other vehicle is a target vehicle when a predetermined first condition is satisfied, the predetermined first condition being that a reflected wave from the second radar reflection point has characteristics of a reflected wave from the other vehicle.

16. 16. The radar object detection system according to claim 15, wherein the blind area is preset based on a position of a radar device mounted on the host vehicle and a traveling direction of the host vehicle.

17. 17. A vehicle identification system comprising: a radar object detection system according to claim 15 or 16; and a driving assistance device configured to issue an alert to a driver of a host vehicle equipped with a radar device when the radar object detection system determines that an object reflecting a radar signal outside a blind area is a target vehicle.

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