JP2016148547A - Detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection device that makes it possible to determine the position of a target using a mirror ghost.SOLUTION: A detection device comprises: a detection unit for detecting a plurality of detection points by a millimeter wave radar 5; a pair extraction unit for extracting a detection point pair P1, P2 from among the plurality of detection points; a pair analysis unit for determining that one of two detection points included in the detection point pair P1, P2 that is closer as a shield detection point W2 deriving from a wall, and that the other is a mirror ghost detection point deriving from the mirror ghost of a target T, a target position determination unit determining the position of the target T on the basis of a first pair P1 and a second pair P2. The target position determination unit determines that one of a position located at equal distance to a mirror ghost detection point G1, with a shield detection point W1 serving as a point of reference, and a position located at equal distance to a mirror ghost detection point G2, with the shield detection point W2 serving as a point of reference, is the position of the target T.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a detection device.

  Conventionally, an inter-vehicle distance sensor described in Patent Document 1 below is known. This inter-vehicle distance sensor detects the position of the road wall, and targets outside the line of the wall are regarded as ghosts and are erased. Accordingly, it has been proposed to prevent a mirror ghost from being detected by reflection of radio waves from the millimeter wave radar by a wall.

Japanese Patent Laid-Open No. 2001-116839

  The mechanism of the inter-vehicle distance sensor as described above merely removes the mirror ghost and does not contribute to the determination of the target position. An object of this invention is to provide the detection apparatus which can determine the position of a target using a mirror ghost.

  The detection device of the present invention is a detection device that detects the position of a target around the host vehicle with an on-vehicle radar, and detects a plurality of detection points by the radar in a place where a shielding object exists, and a radar. A pair extraction unit that extracts a pair of detection points that are positioned in the same direction as a reference and are detected to move synchronously as a detection point pair from a plurality of detection points, and two detections included in the detection point pair A pair analysis unit for determining one of the points as a shielding object detection point derived from the shielding object and determining the other of the two detection points as a mirror ghost detection point derived from the target mirror ghost, and a plurality of detection points extracted A target position determination unit that determines the position of the target based on at least the first pair and the second pair of the pairs, and the target position determination unit detects the shielding object belonging to the first pair. And a position that is equidistant from the mirror ghost detection point belonging to the first pair, and that is equidistant from the mirror ghost detection point belonging to the second pair with reference to the shielding object detection point belonging to the second pair. One of them is determined as the target position.

  ADVANTAGE OF THE INVENTION According to this invention, the detection apparatus which can determine the position of a target using a mirror ghost can be provided.

It is a block diagram of the vehicle provided with the detection apparatus of this invention. It is a top view which shows an example of the road where a detection apparatus is used. It is a flowchart which shows the process of a detection apparatus.

  Hereinafter, embodiments of a detection device according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the detection device 1 is a device that is mounted on a vehicle 3 and detects the position of a target (for example, another vehicle) T around the vehicle 3 with a millimeter wave radar 5. The detection device 1 includes a millimeter wave radar 5 and an ECU 7. The ECU 7 includes a detection unit 11, a pair extraction unit 13, a pair analysis unit 15, and a target position determination unit 17.

  The millimeter wave radar 5 is provided, for example, at the front end of the host vehicle 3 and the rear end of the host vehicle 3 and detects obstacles around the host vehicle 3 using millimeter waves. The millimeter wave radar 5 may be further provided on the side surface of the host vehicle 3 to detect an obstacle on the side of the host vehicle 3. For example, the millimeter wave radar 5 detects an obstacle by transmitting a millimeter wave before and after the host vehicle 3 and receiving a millimeter wave reflected by an obstacle such as another vehicle. The millimeter wave radar 5 transmits the detected obstacle information to the ECU 7. The obstacle information transmitted from the millimeter wave radar 5 to the ECU 7 includes information on the direction and distance of the obstacle viewed from the millimeter wave radar 5. In place of the millimeter wave radar 5, LIDAR [Laser Imaging Detection and Ranging] or the like may be used. In the following description, it is assumed that the millimeter wave radar 5 of the vehicle 3 is provided at the front end of the vehicle body and the side surface of the vehicle body. When it is necessary to distinguish between the two types of millimeter wave radars 5, the one provided at the front end of the vehicle body is referred to as the millimeter wave radar 5a, and the one provided on the side surface of the vehicle body is referred to as the millimeter wave radar 5b.

  The ECU 7 is an electronic control unit having a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. In the ECU 7, functions such as the detection unit 11, the pair extraction unit 13, the pair analysis unit 15, and the target position determination unit 17 are realized by loading a program stored in the ROM into the RAM and executing it by the CPU. The The ECU 7 may be composed of a plurality of electronic control units. Note that some of the functions of the ECU 7 described below may be executed by a computer or a portable information terminal of a facility such as an information management center that can communicate with the host vehicle 3.

  The detection unit 11 detects a plurality of detection points based on the obstacle information from the millimeter wave radar 5 and recognizes the direction and distance of each detection point viewed from the millimeter wave radar 5.

  The pair extraction unit 13 extracts a pair of detection points having a predetermined relationship from the plurality of detection points detected. Specifically, pairs of detection points that are detected so as to move in synchronization in the same direction with respect to the position of the millimeter wave radar 5 are extracted by the pair extraction unit 13. Hereinafter, such a pair of detection points is referred to as a “detection point pair”. For example, the detection point pair is detected so as to be located in the same direction in the horizontal direction.

  The phrase “a pair of detection points moves synchronously” means that the pair of detection points move while maintaining a state in which they are present in the same direction as viewed from the millimeter wave radar 5. In order to detect the detection points of the pair moving synchronously as described above, the pair extraction unit 13 tracks each detection point for a certain time (for example, 1 second) and continues the state in the same direction for a predetermined time. A set of detection points is referred to as a “detection point pair”. Two detection points belonging to the detection point pair always appear to overlap each other when viewed from the millimeter wave radar 5 during the tracking.

  The pair analysis unit 15 determines that one of the two detection points included in the detection point pair is a shielding object detection point, and the other is a mirror ghost detection point. The shielding object detection point originates from the fact that the radar reflected wave from the shielding object (for example, the wall surrounding the road on which the host vehicle 3 travels) returns directly to the millimeter wave radar 5 and the shielding object itself is detected. It is a detection point. The mirror ghost detection point is a detection point derived from the mirror ghost of the target T to be detected. The mirror ghost is a virtual image generated when a radar reflected wave from the target T is reflected by the shielding object and returned to the millimeter wave radar 5, and appears behind the shielding object when viewed from the millimeter wave radar 5. The pair analysis unit 15 determines one of the two detection points included in the detection point pair as having a higher reflection intensity and closer to the millimeter wave radar 5 as a shielding object detection point, and the other as a mirror ghost detection point. Is determined.

  The target position determination unit 17 determines the position of the target T based on at least two pairs (referred to as a first pair and a second pair) located in the same plane among a plurality of extracted detection point pairs. For example, when the first pair and the second pair are located in the same plane, a total of four detection points of two detection points belonging to the first pair and two detection points belonging to the second pair are located in the same plane. It means to do. The same plane is, for example, a horizontal plane. Here, for example, the first pair and the second pair are detected by separate millimeter wave radars 5 such that the first pair is detected by the millimeter wave radar 5a and the second pair is detected by the millimeter wave radar 5b. It may be what was done. Specifically, the target position determination unit 17 detects a shield that is equidistant from the mirror ghost detection point that belongs to the first pair with respect to the shield detection point that belongs to the first pair, and that belongs to the second pair. A position that is equidistant from the mirror ghost detection point belonging to the second pair with respect to the point is set as a candidate for the position of the target T.

  In other words, on the plane where the first pair and the second pair exist, the first virtual circle including the first pair of mirror ghost detection points on the circumference centered on the first pair of shield detection points, Two intersection points with the second virtual circle centering on the two pairs of shield detection points and including the second pair of mirror ghost detection points on the circumference are set as candidates for the position of the target T by the target position determination unit 17. . As can be understood from the geometrical conditions, there are two candidates for the above.

  Further, the target position determination unit 17 determines that the one near the traveling direction of the host vehicle 3 among the above two candidate points is the position of the target T. Specifically, the target position determination unit 17 determines a candidate located on the road and ahead of the traveling direction of the own vehicle at the position of the target T based on the map information of the road on which the own vehicle 3 travels. Judge that there is. In order to enable such determination, the detection apparatus 1 may include a map information database. Further, the traveling direction of the host vehicle 3 may be recognized based on the yaw rate of the host vehicle 3. In order to enable such determination, the detection device 1 may include a yaw rate sensor.

  Hereinafter, the process executed by the ECU 7 will be described with reference to FIGS. FIG. 2 is a plan view showing an example of a state of the road 100 on which the host vehicle 3 travels. FIG. 3 is a flowchart showing a process executed by the ECU 7. The following processing shown in FIG. 3 is repeatedly executed while the host vehicle 3 is traveling, for example.

  Below, as shown in FIG. 2, the process of ECU7 when the own vehicle 3 is drive | working the road 100 which curves to the left is demonstrated as an example. In the state of FIG. 2, there are walls 101 and 102 extending along both sides of the road 100, and a target T (for example, another vehicle) to be detected exists in the traveling direction of the host vehicle 3. Since the millimeter wave is highly straight, the target T cannot be directly detected by the millimeter wave radar 5 because it is blocked by the right wall 102 from the position of the host vehicle 3. In addition, the target T cannot be directly recognized by an in-vehicle camera or the like. The walls 101 and 102 can generate a mirror ghost of the target T by reflecting the millimeter wave used by the millimeter wave radar 5. In FIG. 2, it is assumed that the road surface of the road 100 is on a horizontal plane as a whole, and the own vehicle 3 and the target T exist on the same horizontal plane.

  First, the detection unit 11 detects a plurality of detection points from the obstacle information from the millimeter wave radar 5 and recognizes the direction and distance of each detection point viewed from the millimeter wave radar 5. (Step S1). Hereinafter, when simply saying “the direction of the detection point” or the like, it means the direction of the detection point viewed from the millimeter wave radar 5a or 5b that detected the detection point, and when simply saying “the distance of the detection point” or the like, It means the distance of the detection point seen from the millimeter wave radar 5a or 5b that has detected the detection point.

  Among the many detection points detected here, the detection point W1 is a detection point corresponding to the specific point 101s in the left wall 101 being detected by the millimeter wave radar 5a. The detection point G1 is a detection point corresponding to the radar reflected wave from the target T entering the millimeter wave radar 5a via the specific point 101s. That is, the detection point G1 is a mirror ghost of the target T. Similarly, the detection point W2 is a detection point corresponding to the detection of the specific point 101t in the left wall 101 by the millimeter wave radar 5b. The detection point G2 is a detection point corresponding to the radar reflected wave from the target T further entering the millimeter wave radar 5b via the specific point 101t. That is, the detection point G2 is another mirror ghost of the target T. Here, it is assumed that the detection points G1, G2, W1, and W2 appear on the same horizontal plane.

  Subsequently, the pair extraction unit 13 preferentially selects one detection point from detection points having the longest distance among the detection points having a reflection intensity of a predetermined value or more (step S2). Hereinafter, the detection points selected here are referred to as “attention detection points”. In the example of FIG. 2, the detection point G1 is the target detection point. The pair extraction unit 13 tracks the target detection point and each of the other detection points for a predetermined time (step S3). Then, it is determined whether or not there is a detection point that is detected so as to move in synchronization with the target detection point when viewed from the millimeter wave radar 5, and a detection point that satisfies the condition is extracted. (Step S4). The detection points extracted here are called “synchronization detection points”. In the example of FIG. 2, the detection point W1 is a synchronization detection point. That is, here, the attention detection point G1 and the synchronization detection point W1 are extracted as detection point pairs. On the other hand, when the synchronization detection point is not extracted in step S4, the process returns to step S2.

  When the synchronization detection point is extracted in step S4, the pair analysis unit 15 compares the reflection intensity and the distance between the target detection point and the synchronization detection point (step S5). Here, when the reflected point of the radar reflected wave is stronger than the synchronous detection point and the distance is close, the synchronous detection point is determined as the mirror ghost detection point, and the attention detection point is determined as the shield detection point. (Step S7). On the other hand, when the synchronization detection point has a higher reflection intensity than the attention detection point and is close in distance, the attention detection point is determined as the mirror ghost detection point, and the synchronization detection point is determined as the shielding object detection point (step S6). ). In the case of the example of FIG. 2, the attention detection point G1 becomes a mirror ghost detection point and the synchronization detection point W1 becomes a shielding object detection point via step S6. Thereafter, for example, a set of the attention detection point and the synchronization detection point is temporarily stored as a “detection point pair” in the storage area of the ECU 7 (step S8).

  The processes in steps S2 to S8 described above are repeated until a plurality of detection point pairs located in the same plane are stored in the storage area of the ECU 7, for example (step S9). Hereinafter, as shown in the example of FIG. 2, in the state in which two detection point pairs of the first pair P1 including the detection points G1 and W1 and the second pair P2 including the detection points G2 and W2 are stored, It is assumed that the process proceeds to step S10 described below. The first pair P1 and the second pair P2 are located in the same horizontal plane.

  Next, the target position determination unit 17 is equidistant from the mirror ghost detection point G1 belonging to the first pair P1 with respect to the shielding object detection point W1 belonging to the first pair P1, and belongs to the second pair P2. A position that is equidistant from the mirror ghost detection point G2 belonging to the second pair P2 with respect to the shielding object detection point W2 is set as a candidate for the position of the target T (step S10). That is, on the horizontal plane where the first pair P1 and the second pair P2 exist, the first virtual circle C1 including the mirror ghost detection point G1 on the circumference with the shield detection point W1 as the center, and the shield detection point W2 Two intersections R1 and R2 with the second virtual circle C2 having the mirror ghost detection point G2 on the circumference as a center are candidates for the position of the target T.

  Next, the target position determination unit 17 determines that the one close to the traveling direction of the host vehicle 3 among the above two candidate points is the position of the target T (step S11). Here, as described above, for example, based on the map information of the road on which the host vehicle 3 travels, the candidate (here, the intersection R2) located on the road and ahead of the traveling direction of the host vehicle is the target. It is determined that the position is T. Thus, the position of the target T is determined, and the process ends.

  Then, the effect by the detection apparatus 1 is demonstrated. According to the detection apparatus 1, as described above, the position of the target T can be determined based on the mirror ghost of the target T. As a result, even if the target T cannot be directly detected by the in-vehicle camera or the millimeter wave radar 5 due to a shielding object such as a wall, the mirror T of the target T is used to detect the target T ahead of the host vehicle 3. The position can be determined.

  The present invention can be implemented in various forms including various modifications and improvements based on the knowledge of those skilled in the art including the above-described embodiments. Moreover, it is also possible to comprise the modification of the following Example using the technical matter described in embodiment mentioned above. You may use combining the structure of each embodiment suitably. For example, in the embodiment, a case where a wall surrounding a road is a shielding object is described as an example, but the shielding object may be a guardrail, a tree, a stopped other vehicle, or the like. In the embodiment, the position of the target T is determined based on the two detection point pairs P1 and P2. However, the position of the target T may be determined based on three or more detection point pairs.

  For example, in order to reduce the processing load, if the distance to the mirror ghost detection point obtained in step S6 or S7 is shorter than the distance to the obstacle that is directly detected, it is excluded from the subsequent processing targets. It may be. The obstacle that is directly detected is the one that is located at the longest distance among those having a reflection intensity higher than a predetermined value. Further, when the mirror ghost detection point is within a position range that can be directly detected by another means such as a camera, it may be excluded from the subsequent processing targets. However, in consideration of an obstacle that suddenly jumps out from the blind spot, for example, the mirror ghost as described above indicates that the target T exists in a direction that is difficult to detect directly from the own vehicle 3. For example, a process such as not to exclude the mirror ghost from the processing target may be performed.

  Further, when it is impossible to determine the position of a target T from the state where the position determination of a target T is continuously obtained by repeating the processing of FIG. 3 (for example, there are a plurality of detection point pairs. Think about the process when it is gone. In this case, if the distance from the own vehicle 3 to the determination position of the target T is equal to or greater than a predetermined value, the influence on the own vehicle 3 is relatively small, and the determination position of the target T may be deleted. . On the other hand, if the distance from the own vehicle 3 to the determination position of the target T is less than a predetermined value, the influence on the own vehicle 3 is relatively large, so the position of the target T is continuously predicted by another method. However, the accuracy of the predicted position may be lowered step by step. According to such processing, even when the host vehicle 3 suddenly approaches the target T due to traffic jams or the like, it is possible to respond to the target T with good response.

  DESCRIPTION OF SYMBOLS 1 ... Detection apparatus, 3 ... Own vehicle, 5, 5a, 5b ... Millimeter wave radar (radar), 11 ... Detection part, 13 ... Pair extraction part, 15 ... Pair analysis part, 17 ... Target position determination part, 101, 102 ... wall (shield), G1, G2 ... mirror ghost detection point (detection point), W1, W2 ... shield detection point (detection point), P1 ... first pair (detection point pair), P2 ... second pair ( Detection point pair), T ... target.

Claims (1)

A detection device that detects the position of a target around the host vehicle with an on-vehicle radar,
A detection unit for detecting a plurality of detection points by the radar in a place where a shielding object exists;
A pair extraction unit that extracts a pair of detection points that are detected so as to move in synchronization with each other in the same direction with respect to the radar, as a detection point pair from the plurality of detection points;
Of the two detection points included in the detection point pair, the one closer to the radar is determined as a shield detection point derived from the shield, and the other of the two detection points is a mirror derived from the target mirror ghost. A pair analysis unit for determining a ghost detection point;
A target position determination unit that determines the position of the target based on at least a first pair and a second pair located in the same plane among a plurality of the detected point pairs extracted;
The target position determination unit
Based on the shielding object detection point belonging to the first pair, the second detection object is located at the same distance from the mirror ghost detection point belonging to the first pair, and is based on the shielding object detection point belonging to the second pair. A detection device that determines any one of the positions equidistant from the mirror ghost detection points belonging to a pair as the target position.

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