JP2014119285A - Object detection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an object detection apparatus which can prevent a false target generated by multi-path phenomenon from being falsely recognized as an obstacle.SOLUTION: An object detection apparatus includes: a radar sensor 21 which detects an object near a vehicle C; and a false target determination unit 12 which determines a first object Oas a false target candidate generated by multi-path phenomenon when the amount of temporal change Δθin relative angle θformed by a detection direction θof the first object Odetected by the radar sensor 21 and a detection direction θof a second object Odetected between the vehicle C and the first object Oby the radar sensor 21 is less than a threshold.

Description

  The present invention relates to an object detection device that detects an object around a host vehicle.

  2. Description of the Related Art Conventionally, a radar monitoring apparatus that determines a pseudo target generated by a multipath of radio waves is known as described in JP-A-2006-177858, for example, in relation to an object detection apparatus. When the first target and the second target are moving in the same direction, the radar monitoring apparatus determines that the second target farther than the first target is a multipath pseudo target.

JP 2006-177858 A

  By the way, in an object detection device using an in-vehicle radar, there is a multipath phenomenon in which an electromagnetic wave transmitted from the own vehicle is reflected by a surrounding vehicle and then reflected by a stationary object such as a road sign or road sign and received by the own vehicle. May occur. In this case, there is a possibility that a false target generated by multipath may be erroneously recognized as an obstacle such as a pedestrian.

  Therefore, the present invention intends to provide an object detection device capable of suppressing erroneous recognition of a multi-pass pseudo target as an obstacle.

  An object detection apparatus according to the present invention includes a radar detection unit that detects an object around the host vehicle, a detection direction of the first object detected by the radar detection unit, and a position between the host vehicle and the first object by the radar detection unit. And a pseudo target determination unit that determines that the first object is a multi-pass pseudo target candidate when the temporal change amount of the relative angle formed by the detection direction of the second object detected by the Is provided.

  According to the object detection device of the present invention, the temporal change amount of the relative angle formed by the detection direction of the first object and the detection direction of the second object located between the host vehicle and the first object is less than the threshold value. In this case, it is determined that the first object is a multi-pass pseudo target candidate. This is because when the first object is a multi-pass pseudo target, the detection direction of the first object is defined by the reflecting surface of the side of the second object corresponding to the surrounding vehicle, etc. The detection direction of the second object is defined by the rear reflecting surface, and this is based on the phenomenon that the relative angle between the two detection directions does not change significantly with the passage of time. Multipath (multiwave propagation or multiwave transmission path) refers to a phenomenon in which a transmitted electromagnetic wave follows a plurality of paths until it is received. In addition to a direct wave that connects a shortest distance with a straight line, a reflected wave This is caused by the generation of transmitted waves, diffracted waves, and the like.

  ADVANTAGE OF THE INVENTION According to this invention, the object detection apparatus which can suppress misrecognizing the pseudo target by a multipass | path as an obstruction can be provided.

It is a block diagram which shows the object detection apparatus which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of an object detection apparatus. It is a figure which shows the condition which misrecognizes the false target by a multipass as an obstruction. It is a figure which shows the condition where the misrecognition shown in FIG. 3 is suppressed by the object detection process shown in FIG.

  Hereinafter, an object detection device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, the configuration of an object detection device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an object detection apparatus according to an embodiment of the present invention.

  The object detection device is a device that detects an object in the vicinity of the host vehicle, and in particular, has a function of suppressing erroneous recognition of the object. As shown in FIG. 1, the object detection device is mounted on the host vehicle, and is configured around an electronic control unit 10 (hereinafter abbreviated as ECU 10).

  A radar sensor 21 is connected to the ECU 10. The radar sensor 21 functions as a radar detection unit that detects an object around the host vehicle, particularly an object in the traveling direction of the host vehicle. As the radar sensor 21, for example, a millimeter wave radar, a laser radar, or the like is used. The radar sensor 21 detects an object position by transmitting an electromagnetic wave over a range of a set detection angle and receiving an electromagnetic wave reflected from the object. The position of the object is specified by the detection angle (reception angle) of the electromagnetic wave and the detection distance obtained from the propagation time of the electromagnetic wave required from transmission to reception. The detection angle is represented, for example, as 0 ° in front of the host vehicle, -90 ° in front left of the host vehicle, and + 90 ° in front right.

  A driving support execution unit 22 is connected to the ECU 10. The driving assistance execution unit 22 executes driving assistance such as collision avoidance assistance, collision mitigation assistance, and safe driving assistance. As the driving support execution unit 22, for example, a speaker, a display, an engine control device, a brake control device, a steering control device, a seat belt control device, or the like is used. The driving support execution unit 22 performs control support by providing information support to the driver, intervention for control of the engine system, the brake system, the steering system, the seat belt, and the like.

  The ECU 10 includes a relative angle calculation unit 11, a pseudo target determination unit 12, and a driving support control unit 13. The ECU 10 is configured mainly with a CPU, a ROM, a RAM, and the like, and realizes the functions of the relative angle calculation unit 11, the pseudo target determination unit 12, and the driving support control unit 13 through execution of a program by the CPU. The functions of the relative angle calculation unit 11, the pseudo target determination unit 12, and the driving support control unit 13 may be realized by two or more ECUs.

  The relative angle calculation unit 11 calculates a relative angle formed by the detection direction of the first object detected by the radar sensor 21 and the detection direction of the second object detected by the radar sensor 21. The first object and the second object are objects that are simultaneously detected by the radar sensor 21. The second object is an object detected between the host vehicle and the first object, that is, an object having a detection angle substantially the same as that of the first object and a detection distance shorter than that of the first object. It can be said that the first object is an object detected farther than the second object with reference to the host vehicle. The object detection direction is obtained from the electromagnetic wave detection angle, and the object detection distance is obtained from the electromagnetic wave propagation time.

  The pseudo target determination unit 12 determines whether or not the first object detected by the radar sensor 21 is a multi-path pseudo target candidate. The pseudo target determining unit 12 determines that the first object is a multi-pass pseudo target candidate if the temporal change amount of the relative angle calculated by the relative angle calculating unit 11 is less than the relative angle threshold. . The time variation of the relative angle means a difference between the relative angle at time t and the relative angle at time t + Δt. The relative angle threshold value is set in advance as a larger value as the vehicle length of another vehicle that can be detected as the second object is larger, or as the size of a stationary object that can cause a multipath phenomenon is larger. The pseudo target candidate by multi-pass means a target that is highly likely to be a pseudo target generated by multi-pass.

  The driving support control unit 13 controls driving support based on the determination result by the pseudo target determining unit 12. For example, the driving support control unit 13 calculates a collision possibility based on relative movement information between the host vehicle and an object around the host vehicle, and controls driving support based on the collision possibility. The driving support control unit 13 calculates a lower possibility of collision with the first object as the first object is frequently determined to be a pseudo target candidate by multipath. The driving assistance control unit 13 controls driving assistance based on the detection result of the first object when the possibility of collision with the first object is greater than or equal to the collision threshold.

  Next, the operation of the object detection device will be described with reference to FIGS. FIG. 2 is a flowchart showing the operation of the object detection apparatus. The object detection apparatus repeatedly executes the process shown in FIG. 2 every set period Δt.

  The relative angle calculation unit 11 determines whether or not the first object and the second object are detected based on the detection result of the radar sensor 21 (S11). In the detection determination, it is determined whether or not two or more objects are detected simultaneously, that is, whether or not they are detected in the same processing cycle. In the detection determination, it may be determined whether two or more objects are simultaneously detected in the same or substantially the same direction. This is because when the detection directions are greatly different, the first object cannot be a pseudo target candidate generated by multipath due to the presence of the second object.

  When it is determined that the first object and the second object are detected, the relative angle calculation unit 11 calculates the relative angle formed by the detection direction of the first object and the detection direction of the second object (S12). The relative angle is obtained as an absolute value of a difference between the detection direction of the first object and the detection direction of the second object. The calculation result of the relative angle is stored in a memory or the like until at least the next processing cycle. If it is determined that the first object and the second object are not detected, the driving assistance is controlled based on the detection result of the radar sensor 21 in S16.

  When the relative angle is calculated, the pseudo target determining unit 12 determines whether or not the temporal change amount of the relative angle is less than the relative angle threshold (S13). The time change amount of the relative angle is obtained as an absolute value of a difference between the relative angle in the previous processing cycle and the relative angle in the current processing cycle.

  When it is not determined that the temporal change amount of the relative angle is less than the threshold, the pseudo target determination unit 12 determines that the first object is an obstacle (S14). On the other hand, when it is determined that the temporal change amount of the relative angle is less than the threshold, the pseudo target determining unit 12 determines that the second object is a multi-pass pseudo target candidate (S15).

  The driving assistance control unit 13 calculates the collision possibility based on the relative movement information between the host vehicle and the object, particularly the first object, and controls the driving assistance based on the collision possibility (S16). The driving support control unit 13 calculates a lower possibility of collision with the first object as the first object is frequently determined to be a pseudo target candidate by multipath. The driving support control unit 13 controls driving support such as notification support and control support based on the detection result of the first object when the possibility of collision with the first object is equal to or greater than the collision threshold.

FIG. 3 is a diagram illustrating a situation where a multi-pass pseudo target is erroneously recognized as an obstacle. In the situation shown in FIG. 3, the second object O ₂ , which is an adjacent vehicle, is parallel to the own vehicle C in the front right of the own vehicle C, and a road sign is in front of the own vehicle C and the second object O _2. A stationary object S such as a road signboard exists. In such a situation, the electromagnetic wave transmitted from the host vehicle C is specularly reflected by the side surface of the second object O ₂ , for example, the glass surface of the side window, then reflected by the stationary object S, and again the side surface of the second object O ₂ . There is a case where the phenomenon of being reflected by the vehicle C and received by the own vehicle C may occur.

In the situation at time t shown in FIG. 3A, the first object O ₁ is detected in the front right of the host vehicle C due to the stationary object S located in the front left of the host vehicle C. The position of the first object O ₁ is specified by the detection direction θ ₁ (t) and the detection distance d ₁₁ (t) + d ₁₂ (t) toward the side surface of the second object O ₂ with reference to the host vehicle C. The distance d ₁₁ (t) corresponds to the propagation distance from the host vehicle C to the side surface of the second object O ₂ at time t, and the distance d ₁₂ (t) is from the side surface of the second object O ₂ to the stationary object S. It corresponds to the propagation distance of.

In the situation at time t + Δt shown in FIG. 3B, the detection direction θ ₁ (t + Δt) and the detection distance d ₁₁ (t + Δt) + d ₁₂ (t + Δt) toward the side surface of the second object O ₂ with respect to the host vehicle C. The first object O ₁ is detected at the position specified by. The distance d ₁₁ (t + Δt) corresponds to the propagation distance from the own vehicle C to the side surface of the second object O ₂ at time t + Δt, and the distance d ₁₂ (t + Δt) is from the side surface of the second object O ₂ to the stationary object S. Corresponds to the propagation distance.

Based on such a detection result, the first object O ₁ , which is a pseudo target generated by a multipath caused by the stationary object S, is stationary in the traveling direction of the host vehicle C, and in a direction orthogonal to the traveling direction. There is a risk of being erroneously recognized as an obstacle moving from right to left.

FIG. 4 is a diagram illustrating a situation in which the erroneous recognition illustrated in FIG. 3 is suppressed by the object detection process illustrated in FIG. At time t shown in FIG. 4A, the vehicle is an adjacent vehicle at a position specified by the direction θ ₂ (t) toward the rear surface of the second object O ₂ and the detection distance d ₂ (t) with respect to the host vehicle C. A second object O ₂ is detected. Further, the first object O ₁ is detected at a position specified by the direction θ ₁ (t) toward the side surface of the second object O ₂ and the detection distance d ₁₁ (t) + d ₁₂ (t). Then, theta relative angle between detection direction theta ₁ of the first object _{O 1} (t) and the detection direction theta ₂ of the second object _{O 2} (t) is _{r (t) = | θ 2} (t) -θ 1 (T) | is required.

At time t + Δt shown in FIG. 4B, the second position is determined by the direction θ ₂ (t + Δt) toward the rear surface of the second object O ₂ and the detection distance d ₂ (t + Δt) with reference to the host vehicle C. object O ₂ is detected. Further, the first object O ₁ is detected at a position specified by the direction θ ₁ (t + Δt) toward the side surface of the second object O ₂ and the detection distance d ₁₁ (t + Δt) + d ₁₂ (t + Δt). As a relative angle formed by the detection direction θ ₁ (t + Δt) of the first object O _{1 and} the detection direction θ2 (t + Δt) of the second object O ₂ , θ _r (t + Δt) = | θ ₂ (t + Δt) −θ ₁ ( t + Δt) |.

Based on such a detection result, it is determined whether or not the first object O ₁ is a multi-pass pseudo target candidate. That is, when the amount of change in the relative angle with time, that is, Δθ _r = | θ _r (t + Δt) −θ _r (t) | is less than the threshold, the first object O ₁ is a pseudo target candidate by multipath, in other words, Then, it is determined that the target is a pseudo target candidate generated by the reflection of the electromagnetic wave in the first object O ₁ . This suppresses erroneous recognition of a multi-pass pseudo target as an obstacle. And it is suppressed that improper driving assistance is performed by regarding a multi-pass pseudo target as an obstacle.

  As described above, according to the object detection device according to the embodiment of the present invention, the relative angle formed by the detection direction of the first object and the detection direction of the second object located between the host vehicle and the first object. Is less than the threshold, it is determined that the first object is a multi-pass pseudo target candidate. This is because when the first object is a multi-pass pseudo target, the detection direction of the first object is defined by the reflecting surface of the side of the second object corresponding to the surrounding vehicle, etc. The detection direction of the second object is defined by the rear reflecting surface, and this is based on the phenomenon that the relative angle between the two detection directions does not change significantly with the passage of time.

  The above-described embodiment describes the best embodiment of the object detection device according to the present invention, and the object detection device according to the present invention is not limited to the one described in this embodiment. . The object detection apparatus according to the present invention may be modified from the object detection apparatus according to the present embodiment or applied to other objects without departing from the gist of the invention described in each claim.

  For example, FIG. 4 shows a case where an adjacent vehicle traveling in the same direction as the own vehicle is detected as the second object, but an adjacent vehicle traveling in the opposite direction to the own vehicle is detected as the second object. The same can be said for the case of the case.

  DESCRIPTION OF SYMBOLS 10 ... Electronic control unit (ECU), 11 ... Relative angle calculation part, 12 ... Pseudo target determination part, 13 ... Driving assistance control part, 21 ... Radar sensor, 22 ... Driving assistance execution part.

Claims (4)

A radar detector for detecting objects in the vicinity of the vehicle;
Time variation of relative angle between the detection direction of the first object detected by the radar detection unit and the detection direction of the second object detected between the host vehicle and the first object by the radar detection unit. Is less than the threshold, the pseudo target determination unit that determines that the first object is a multi-target pseudo target candidate;
An object detection apparatus comprising:   The object detection apparatus according to claim 1, wherein the first object and the second object are objects that are simultaneously detected in the same or substantially the same direction.   The threshold value is set in advance as a larger value as the average vehicle length of other vehicles that can be detected as the second object is larger, or as the size of a stationary object that can cause a multipath phenomenon is larger. Or the object detection apparatus of 2.   The driving support control unit further calculates a lower possibility of collision with the first object as the first object is frequently determined to be the pseudo target candidate by multipath. The object detection apparatus according to any one of claims.

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