JP2006292475A - Object detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an object detector for detecting an object with high accuracy. <P>SOLUTION: This object detector 1 for detecting an object based on radar-acquired information and image-acquired information, is equipped with: a radar detection means 2 for detecting an object by means of radar; an image detection means 3 for detecting an object by means of an image; and a determination means 8 for determining that the object detected by the detection means 2 is identical with the object detected by the detection means 3 if a criterion is satisfied by a relation between positional information on the object detected by the detection means 2 and positional information on the object detected by the detection means 3. This detector 1 is characterized by changing the criterion for making it easier to determine that the objects are identical with each other if the distance to the objects are long. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an object detection apparatus that detects an object based on information from a radar and information from an image.

In recent years, driving support devices such as a collision reducing device, an inter-vehicle distance control device, and a following traveling device have been developed. In these driving assistance devices, it is important to detect a vehicle traveling in front of the host vehicle. In order to improve the detection accuracy, the object detection apparatus includes an apparatus including two detection means, that is, a detection means using a radar such as a millimeter wave radar and a detection means using an image such as a stereo camera. In the object detection apparatus including these two detection means, the radar detection object detected based on the information from the radar and the image detection object detected based on the information from the image are collated, and the radar detection object and the image detection object are detected. It is determined whether or not they are the same object, and the object determined to be the same is set as an object to be detected such as a vehicle (see Patent Document 1).
JP 2004-117071 A

  In the object detection based on information by an image, the detection accuracy decreases as the detection target object is farther away (particularly, the distance accuracy to the object decreases). For this reason, when the radar detection object and the low-accuracy image detection object are collated with respect to an object existing in the distance, the collation accuracy also decreases. As a result, even if the radar detection object and the image detection object are the same object, it may not be determined as the same object by collation, and there is a possibility that the object to be detected cannot be set.

  Therefore, an object of the present invention is to provide an object detection device that detects an object with high accuracy.

  An object detection apparatus according to the present invention includes a radar detection means for detecting an object by radar, an image detection means for detecting an object by an image, position information of the object detected by the radar detection means, and an object detected by the image detection means. When the object detected by the radar detection means and the object detected by the image detection means are judged to be the same object when the relationship with the position information satisfies the determination criteria, and the distance to the object is long Is characterized in that the judgment criterion is changed so that it can be easily judged as the same object.

  In this object detection apparatus, an object is detected based on radar information from the radar detection means, and position information obtained from the radar information is acquired for the detected object. Further, the object detection device detects an object based on the image information obtained by the image detection means, and acquires position information obtained from the image information for the detected object. In the object detection device, the determination unit determines whether or not the relationship between the position information of the detection object detected by the radar detection unit and the position information of the detection object detected by the image detection unit satisfies the determination criterion. In this case, the detection objects detected by the detection means are determined to be the same object. At this time, in the object detection means, when the distance to the object (for example, the distance to the object obtained from the radar information) is long (that is, when the object detected by the detection means exists on the far side), the determination criteria are the same. Change it so that it can be easily determined as an object. As described above, in the object detection device, when the object exists on the far side, the determination reference is relaxed, so that the detection object by the radar detection unit and the detection object by the image detection unit can be easily determined as the same object. Therefore, in the object detection device, even when the object exists on the far side and the detection accuracy for the object by the image detection means is lowered, the object detected by the image detection means is determined to be the same object as the detection object by the radar detection means. can do. As a result, the object detection means can detect the detection target object with high accuracy regardless of the distance to the object.

  In the object detection apparatus of the present invention, the determination means detects the radar detection means when the relationship between the position information of the object detected by the radar detection means and the position information of the object detected by the image detection means is less than a predetermined value. If the object and the object detected by the image detection means are determined to be the same object, and the distance to the object is long, the predetermined value may be increased.

  In this object detection device, the determination means determines whether the relationship between the position information of the detected object by the radar detection means and the position information of the detection object by the image detection means is less than a predetermined value. The objects detected by the detecting means are determined to be the same object. At this time, in the object detection apparatus, when the distance to the object is long, the predetermined value is changed to a large value so that it can be easily determined that the object is the same.

  According to the present invention, the object can be detected with high accuracy by changing the determination criterion according to the distance to the object.

  Hereinafter, an embodiment of an object detection device according to the present invention will be described with reference to the drawings.

  In the present embodiment, the object detection device according to the present invention is applied to a collision mitigation device mounted on a vehicle. The collision mitigation apparatus according to the present embodiment detects a forward vehicle as a detection target and performs various controls to prevent / reduce a collision with the forward vehicle. In particular, the collision mitigation apparatus according to the present embodiment includes two sensors, a millimeter wave radar and a stereo camera, for detecting a vehicle ahead, and collates a detection object by the millimeter wave radar with a detection object by the stereo camera. To detect the vehicle ahead. In this embodiment, there are two forms depending on the difference in the collation processing. The first embodiment is a form in which the tracking process for the detected object is not performed for each sensor, and the second embodiment is for each sensor. This is a form for performing tracking processing on a detected object.

  With reference to FIGS. 1-7, the collision mitigation apparatus 1 which concerns on 1st Embodiment is demonstrated. FIG. 1 is a configuration diagram of a collision mitigation device according to the present embodiment. FIG. 2 is an explanatory diagram of a radar target, a stereo image target, and a fusion target according to the present embodiment. FIG. 3 is an explanatory diagram of a collation method between the previous fusion target and the radar target according to the first embodiment. FIG. 4 is an explanatory diagram of a collation method between the previous fusion target and the stereo image target according to the first embodiment. FIG. 5 is an explanatory diagram of a method for collating a radar target and a stereo image target according to the present embodiment. FIG. 6 is a diagram showing threshold values when an object is present in the vicinity in the collation between the radar object and the stereo image target according to the present embodiment. FIG. 7 is a diagram illustrating threshold values when an object exists far away in the collation between the radar object and the stereo image target according to the present embodiment.

  The collision mitigation device 1 detects a vehicle ahead and performs brake control, suspension control, seat belt control, and alarm control according to the possibility of collision when a front object is detected. The collision mitigation apparatus 1 sets a radar target based on information from a millimeter wave radar and sets a stereo image target based on a stereo image from a stereo camera in order to detect a vehicle ahead. A fusion target (vehicle ahead) is set by collating with the image target. At this time, the collision mitigation apparatus 1 collates the radar target or stereo image target with the previous fusion target without tracking each of the radar target and the stereo image target. In particular, in the collision mitigation apparatus 1, in order to improve the detection accuracy regardless of the distance to the preceding vehicle, the distance threshold is set according to the distance to the object when collating the radar target with the stereo image target. change. The collision mitigation apparatus 1 includes a millimeter wave radar 2, a stereo camera 3, a brake ECU [Electronic Control Unit] 4, a suspension control actuator 5, a seat belt actuator 6, a buzzer 7, a collision mitigation ECU 8, and the like. Various signals are transmitted and received via Network (standard interface standard for in-vehicle LAN) communication.

  In this embodiment, the millimeter wave radar 2 corresponds to the radar detection means described in the claims, the stereo camera 3 corresponds to the image detection means described in the claims, and the collision reduction ECU 8 is patented. This corresponds to the determination means described in the claims.

  First, each target will be described with reference to FIG. The radar target is an object detected based on information from the millimeter wave radar 2. In the radar target, the distance to the object that can be acquired from the radar information, the lateral position of the object, and the relative speed with the object are set. The stereo image target is an object detected based on a stereo image obtained by the stereo camera 3. For stereo image targets, the distance to the front end surface of the object that can be acquired from the stereo image, the horizontal position of the center of the front end surface of the object, the relative speed with the object, the width of the object (the length in the left-right direction with respect to the host vehicle) The depth of the object (the length in the direction away from the host vehicle), the height of the object, and the height position of the object are set. The fusion target is an object that has a high similarity in the collation between the radar target and the stereo image target, and can determine that the radar target and the stereo image target are the same object. In the fusion target, the distance and relative speed from the radar target and the horizontal position, width, depth, height, and height position from the stereo image target are set. Information on this fusion target is information about the vehicle ahead.

  The millimeter wave radar 2 is a radar for detecting an object using millimeter waves. The millimeter wave radar 2 is attached to the front center of the host vehicle. The millimeter wave radar 2 transmits the millimeter wave forward while scanning the millimeter wave in a horizontal plane, and receives the reflected millimeter wave. The millimeter wave radar 2 transmits the millimeter wave transmission / reception data to the collision mitigation ECU 8 as a radar signal.

  The stereo camera 3 is composed of two CCD cameras, and the two CCD cameras are arranged at a predetermined interval in the horizontal direction. The stereo camera 3 is also attached to the front center of the host vehicle. The stereo camera 3 transmits left and right stereo image data captured by the two CCD cameras to the collision reduction ECU 8 as image signals.

  The brake ECU 4 is an ECU that adjusts the hydraulic pressure of each wheel cylinder of the four wheels and controls the braking force of the four wheels. The brake ECU 4 sets a hydraulic control signal based on the target braking force of each wheel, and transmits each hydraulic control signal to a brake control actuator that changes the hydraulic pressure of each wheel cylinder. In particular, when the brake ECU 4 receives a target brake force signal for each wheel from the collision reduction ECU 8, the brake ECU 4 sets a hydraulic control signal based on the target brake force indicated by the target brake force signal. Incidentally, when receiving the hydraulic control signal, the brake control actuator changes the hydraulic pressure of the wheel cylinder based on the target hydraulic pressure indicated by the hydraulic control signal.

  The suspension control actuator 5 is an actuator that changes the hydraulic pressure of each hydraulic active suspension of the four wheels. When the suspension control actuator 5 receives the target damping force signal for each wheel from the collision reduction ECU 8, the suspension control actuator 5 sets the target hydraulic pressure based on the target damping force indicated by each target damping force signal, and the hydraulic active suspension based on the target hydraulic pressure. Change the oil pressure. Although only one suspension control actuator 5 is shown in FIG. 1, it is provided for each of the four wheel suspensions.

  The seat belt actuator 6 is an actuator that pulls in each seat belt and changes the restraining force by the seat belt. When the seat belt actuator 6 receives a target pull-in amount signal for each seat belt from the collision reduction ECU 8, the seat belt actuator 6 pulls in the seat belt according to the target pull-in amount indicated by each target pull-in amount signal. In FIG. 1, only one seat belt actuator 6 is illustrated, but each seat belt actuator 6 is provided for each seat belt.

  When the buzzer 7 receives an alarm signal from the collision reduction ECU 8, it outputs a buzzer sound.

  The collision mitigation ECU 8 is an electronic control unit including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like, and comprehensively controls the collision mitigation apparatus 1. The collision mitigation ECU 8 takes in the radar signal from the millimeter wave radar 2 and each image signal from the stereo camera 3 at regular intervals based on the master clock of the CPU. Then, the collision mitigation ECU 8 performs a radar target setting process based on radar information and a stereo image target setting process based on the stereo image at regular intervals, and the previous fusion target, the current radar target, and the stereo image target. The collation process based on is performed, and the fusion target is set this time. Further, the collision mitigation ECU 8 performs a collision mitigation process based on the relationship between the current fusion target (front vehicle) and the host vehicle.

  The radar target setting process will be described. The collision mitigation ECU 8 calculates the distance to the object ahead based on the time from when the millimeter wave is emitted to when it is received. Further, the collision reduction ECU 8 calculates a relative speed with respect to a front object. In addition, the collision mitigation ECU 8 detects the direction of the millimeter wave that has been reflected most strongly among the reflected millimeter waves, obtains the angle formed by the traveling direction of the host vehicle and the direction of the object from that direction, and based on that angle Calculate the horizontal position. In the object detection by the millimeter wave radar 2, since the object is detected when the reflected millimeter wave is received, one radar target is obtained every time the reflected millimeter wave is received. Further, in the object detection by the millimeter wave radar 2, the distance to the object can be accurately detected, and thus the accuracy of the distance and the relative speed is particularly high.

  The stereo image target setting process will be described. The collision mitigation ECU 8 triangulates the front object in three dimensions using the difference in the appearance of the object in the left and right stereo images, and the position from the stereo camera 3 to the object (distance to the front end surface of the object). The horizontal position of the front end surface of the object, the height position of the object) are calculated, and the three-dimensional size (horizontal width, depth, height) of the object is calculated. Further, the collision reduction ECU 8 calculates a relative speed with respect to a front object. In the object detection by the stereo camera 3, the object is detected when the object can be specified from the left and right stereo images, so that one stereo image target is obtained each time the object is specified. Further, in the object detection by the stereo camera 3, since the object can be detected three-dimensionally, information on the size of the object can be acquired.

  The verification process will be described. First, the collision reduction ECU 8 collates the previous fusion target and the current radar target at regular time intervals. Specifically, as shown in FIG. 3, the collision mitigation ECU 8 sets a distance threshold and a lateral position threshold around the position (distance, lateral position) of the previous fusion target LF (as indicated by the broken line in FIG. 3). The relative velocity threshold is set with the relative velocity of the previous fusion target LF as the median value. Then, the collision mitigation ECU 8 determines whether or not the position (distance, lateral position) of the current radar target TL is within the distance threshold and the lateral position threshold centered on the position of the previous fusion target LF. At the same time, it is determined whether or not the relative speed of the radar target TL is within the relative speed threshold value. Then, the collision mitigation ECU 8 determines that the current radar target TL is similar to the previous fusion target LF when it is within all the thresholds in this determination, and if even one is not within the threshold. It is determined that there is no similarity. In this collation, collation is performed in consideration of position information held by the radar target with the previous fusion target in which highly accurate information is set as the center.

  Further, the collision reduction ECU 8 collates the previous fusion target with the current stereo image target at regular time intervals. Specifically, as shown in FIG. 4, the collision mitigation ECU 8 sets the distance threshold value, the horizontal position threshold value, and the height position value about the position (distance, horizontal position, height position) of the previous fusion target LF. In addition to setting a threshold value, a threshold value for the depth of the object, a threshold value for the width of the object, and a threshold value for the height of the object (see the three-dimensional area indicated by the broken line in FIG. 4), and the relative speed of the previous fusion target LF as the median value Set the relative speed threshold. Then, in the collision mitigation ECU 8, the position (distance, lateral position, height) of the current stereo image target TI is within the threshold of the distance centered on the position of the previous fusion target LF and within the threshold of the lateral position and the height position. Whether or not the size (depth, width, height) of the current stereo image target TI is within the depth threshold, the width threshold, and the height threshold. At the same time, it is determined whether or not the relative speed of the stereo image target TI is within the relative speed threshold value. Then, the collision mitigation ECU 8 determines that the current stereo image target TI is similar to the previous fusion target LF when it is within all the thresholds in this determination, and even one of them is not within the threshold. It is determined that there is no similarity in the case. In this collation, collation is performed in consideration of the size information of the three-dimensional object with respect to the position information held by the stereo image target with the previous fusion target in which highly accurate information is set as the center.

  When there are a current radar target and a current stereo image target that are similar to the previous fusion target, the collision mitigation ECU 8 compares the current radar target with the current stereo image target. Specifically, as shown in FIG. 5, the collision mitigation ECU 8 sets a distance threshold and a lateral threshold with the position (distance, lateral position) of the current radar target TL as the center, and a depth threshold of the object. Then, the threshold value of the horizontal width of the object is set (see the plane area indicated by the broken line in FIG. 5), and the relative speed threshold value is set with the relative speed of the current radar target TL as the median. Then, the collision mitigation ECU 8 determines whether or not the position (distance, lateral position) of the current stereo image target TI is within the distance threshold and the lateral position threshold with the position of the current radar target TL as the center. It is determined whether or not the size (depth, width) of the stereo image target TI is within the depth threshold and the width threshold, and the relative speed of the stereo image target TI is within the relative speed threshold. It is determined whether or not. Then, the collision mitigation ECU 8 determines that the current radar target TL and the current stereo image target TI are similar if they are within all the thresholds in this determination, and even one of them is within the threshold. If not, it is determined that there is no similarity. If it is determined that there is a similarity, the collision mitigation ECU 8 updates the previous fusion target as the current fusion target, sets the distance and relative speed of the current radar target as information on the current fusion target, and the current stereo image. Set the horizontal position, width, depth, height, and height position of the target. On the other hand, when it is determined that there is no similarity, the collision reduction ECU 8 deletes the previous fusion target. In this collation, the distance accuracy is high, the current radar target with the horizontal position at the center of the object is the center, and the stereo image target has the position information held by the radar target and the stereo image target. Matches in consideration of size information.

  When the current radar target and the current stereo image that are not similar to the updated current fusion target remain, the collision reduction ECU 8 determines whether the remaining current radar target and the current stereo image target are the same. Perform verification. This collation method is a collation method similar to the above-described current radar target and the current stereo image. In the collision mitigation ECU 8, if there is a current radar target and a current stereo image that are determined to be similar, this is newly set as the current fusion target, and each information of the current fusion target is set in the same manner as described above. .

  In the object detection by the stereo camera 3, the detection accuracy with respect to the object decreases as the object is located farther away. In particular, since the accuracy of the distance to the object is reduced, even if the same object is detected, a distant object between the distance set for the stereo image target and the distance set for the radar target Differences can occur. For this reason, even if an object located far away is detected by the object detection by the millimeter wave radar 2 and the object detection by the stereo camera 3, it may not be determined as the same object in the collation. Therefore, when the distance of a radar target with high distance accuracy is long (that is, when the detected object is far away), the threshold of the distance is increased (that is, the reference for determining the same object is determined as the same object). To a standard that is easy to do). As a result, the distance accuracy in the object detection by the stereo camera 3 with respect to a distant object is lowered, and there is a certain difference between the distance set for the stereo image target and the distance set for the radar target. However, in the collation, the target falls within the distance threshold and the fusion target can be set.

  Specifically, before collating the current radar target TL with the current stereo image target TI, the collision reduction ECU 8 determines whether or not the distance of the current radar target TL is equal to or less than the distance reference T. When the distance of the radar target TL this time is equal to or less than the distance reference T, the collision reduction ECU 8 sets A (strict reference value) as a distance threshold with the position of the current radar target TL as the center, and the lateral position threshold. W is set as (see FIG. 6). On the other hand, when the distance of the radar target TL this time is equal to or less than the distance reference T, the collision reduction ECU 8 sets B (a loose reference value) larger than A as the distance threshold with the position of the current radar target TL as the center. W is set as the threshold for the horizontal position (see FIG. 7).

  When there are a plurality of targets to be collated in each collation (for example, when there are a plurality of radar targets this time), collation is performed for all combinations. Each threshold value is set in advance in consideration of detection accuracy by the millimeter wave radar 2 and the stereo camera 3, and stored in the collision mitigation ECU 8. The distance threshold and the relative speed threshold may be variable in consideration of the vehicle speed of the host vehicle. Depth, width, and height represent the size of the object. Since the detection target is a vehicle, the threshold values of depth, width, and height are set based on the size of a general vehicle. In particular, the distance reference T and the distance thresholds A and B are set in consideration of the performance of the stereo camera 3 and the distance accuracy in object detection by the stereo camera 3.

  The collision mitigation process will be described. When there is a fusion target this time (that is, when there is a forward vehicle), the collision reduction ECU 8 considers the vehicle speed and is a stage of possibility of a collision based on the distance information set for the current fusion target ( For example, three stages of high possibility, low possibility, and none are set. Then, the collision reduction ECU 8 controls the brake ECU 4, the suspension control actuators 5,..., The seat belt actuators 6,.

  The case where there is a three-stage possibility of collision of this control will be described as an example. In a stage where there is no possibility of a collision, the collision reduction ECU 8 does not control the brake ECU 4, the suspension control actuators 5,..., The seat belt actuators 6,.

  At a stage where the possibility of a collision is low, the collision reduction ECU 8 does not control the brake ECU 4 and the suspension control actuators 5, but controls the seat belt actuators 6,. Specifically, the collision reduction ECU 8 sets a target pull-in amount signal for slightly retracting the seat belt in order to notify that the vehicle is approaching ahead, and the target pull-in amount signal is set as the seat belt actuator 6,. ... (Send to only the seat belt actuator 6 in the driver's seat). Further, the collision mitigation ECU 8 sets an alarm signal to notify that the vehicle is approaching ahead, and transmits the alarm signal to the buzzer 7.

  At a stage where the possibility of a collision is high, the collision reduction ECU 8 controls the brake ECU 4, the suspension control actuators 5,..., The seat belt actuators 6,. Specifically, the collision reduction ECU 8 sets a target brake force signal for decelerating the vehicle, and transmits the target brake force signal to the brake ECU 4. Further, the collision mitigation ECU 8 sets a target damping force signal for preventing the vehicle from tilting (so that the front portion does not sink), and sends the target damping force signal to the suspension control actuators 5,. Send. Further, the collision reduction ECU 8 sets a target pull-in amount signal for strongly restraining the occupant, and transmits the target pull-in amount signal to the seat belt actuators 6,. Further, the collision mitigation ECU 8 sets an alarm signal to notify that the vehicle is approaching ahead, and transmits the alarm signal to the buzzer 7.

  In addition to the possibility of collision, the amount of overlap with the vehicle ahead is also determined, and the brake ECU 4, suspension control actuators 5,..., Seat belt actuators 6,. The buzzer 7 may be controlled.

  With reference to FIGS. 1-7, the operation | movement in the collision mitigation apparatus 1 is demonstrated. In particular, the flow of collation processing in the collision reduction ECU 8 will be described with reference to the flowchart of FIG. FIG. 8 is a flowchart showing a flow of collation processing according to the first embodiment.

  The millimeter wave radar 2 transmits the millimeter wave forward and receives the reflected millimeter wave, and transmits the transmission / reception data as a radar signal to the collision mitigation ECU 8. In the stereo camera 3, the front is imaged, and the captured left and right stereo images are transmitted to the collision reduction ECU 8 as image signals.

  The collision mitigation ECU 8 receives a radar signal from the millimeter wave radar 2 and receives each image signal from the stereo camera 3. Then, the collision mitigation ECU 8 sets a radar target based on radar information based on radar signals at regular time intervals. Also. The collision mitigation ECU 8 sets a stereo image target based on the left and right stereo images of each image signal at regular intervals.

  Then, the collision reduction ECU 8 performs the following verification process at regular intervals. The collision reduction ECU 8 collates the previous fusion target with the radar target based on the distance, the position information of the lateral position, and the relative speed (S10). Further, the collision mitigation ECU 8 collates the previous fusion target with the stereo image target based on the position information on the distance, the horizontal position, the height position, the depth, the width, the height information, and the relative speed (S11). ).

  If there are a radar target and a stereo image target similar to the previous fusion target, the collision mitigation ECU 8 determines whether the distance of the radar target is equal to or less than the distance reference T (S12). . When it is determined in S12 that the distance is equal to or less than the distance reference T, the collision reduction ECU 8 sets A as a distance threshold (S13). On the other hand, when it is determined in S12 that the distance is longer than the distance reference T, the collision reduction ECU 8 sets B (> A) as a distance threshold (S14).

  When the distance threshold is set, the collision mitigation ECU 8 determines the radar target and the stereo image target similar to the previous fusion target based on the distance, the position information of the lateral position, the depth, the width information, and the relative speed. (S15).

  The collision reduction ECU 8 determines whether or not there is similarity in the collation in S15 (S16). If it is determined that there is similarity in S16, the collision reduction ECU 8 updates the previous fusion target that has been collated to the current fusion target, and the distance and relative velocity of the radar target as information of the current fusion target. And the horizontal position, width, depth, height, and height position of the stereo image target are set (S17). At this time, the similar radar target and stereo image target are deleted. On the other hand, if it is determined in S16 that there is no similarity, the collision reduction ECU 8 deletes the previous fusion target that has been collated (S18). The processing from S10 to S18 is performed for all combinations of all previous fusion targets, all radar targets, and all stereo image targets. By the processing so far, the tracking for the previous fusion target is completed.

  When the radar target and the stereo image target remain, the collision reduction ECU 8 determines whether or not the distance of the radar target is equal to or less than the distance reference T (S19). When it is determined in S19 that the distance is equal to or less than the distance reference T, the collision reduction ECU 8 sets A as a distance threshold (S20). On the other hand, when it is determined in S19 that the distance is longer than the distance reference T, the collision reduction ECU 8 sets B (> A) as a distance threshold (S21).

  When the distance threshold is set, the collision reduction ECU 8 collates the remaining radar target with the stereo image target based on the distance, the position information of the lateral position, the depth, the size information of the lateral width, and the relative speed (S22). ).

  The collision reduction ECU 8 determines whether or not there is similarity in the collation in S22 (S23). When it is determined that there is similarity in S23, the collision reduction ECU 8 sets the current fusion target based on the similar radar target and the stereo image target, and the radar as information on the current fusion target. The distance and relative speed of the target are set, and the horizontal position, width, depth, height, and height position of the stereo image target are set (S24). The processes from S19 to S24 are performed for all combinations of all remaining radar targets and all stereo image targets. By the processing so far, the collation processing of all radar targets and all stereo image targets is completed.

  When the previous fusion target has not been set, the collision reduction ECU 8 performs the verification process from the process of S19 without performing the processes of S10 to S18. If no radar target or stereo image target remains after the current fusion target is updated, the collision reduction ECU 8 ends the current collation process without performing the processes of S19 to S24. In addition, when at least one of the radar target and the stereo image target is not set, the current matching process is not performed.

  When the current fusion target is set by the collation process, the collision reduction ECU 8 sets the stage of possibility of collision based on the information set in the fusion target, and according to the stage of possibility of collision. The brake ECU 4, suspension control actuators 5,..., Seat belt actuators 6,. With this control, when the possibility of a collision with the preceding vehicle is low, the driver is made aware of the approach of the preceding vehicle by retracting the seat belt by the seat belt actuators 6... And outputting a buzzer sound by the buzzer 7. Further, when the possibility of a collision with the vehicle ahead increases, deceleration by the automatic braking force by the brake ECU 4 and suspension hardness adjustment by the suspension control actuators 5,... By further pulling in the belt, the occupant is strongly restrained, and the buzzer 7 outputs a buzzer sound to allow the driver to recognize further approach of the preceding vehicle. On the other hand, when the current fusion target is not set by the collation process, the collision reduction ECU 8 does not perform the current collision reduction process.

  According to the collision mitigation apparatus 1, the distance threshold is changed according to the distance to the object. Therefore, even when the object detection accuracy by the stereo camera 3 is reduced with respect to the far front vehicle, Similarly to the above, the vehicle ahead can be detected with high accuracy.

  In addition, according to the collision mitigation apparatus 1, since the size information is used for collation in addition to the position information, the collation can be performed in consideration of the size of the vehicle to be detected. It can be detected with accuracy. Furthermore, according to the collision mitigation apparatus 1, since the collation is performed using the relative speed, it is possible to detect the vehicle ahead as a moving body with higher accuracy.

  A collision mitigation device 11 according to a second embodiment will be described with reference to FIGS. 1, 2, and 5 to 7. In the collision mitigation device 11, the same components as those in the collision mitigation device 1 according to the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The collision mitigation device 11 differs from the collision mitigation device 1 in radar target setting processing, stereo image target setting processing, and collation processing. That is, the collision mitigation apparatus 11 tracks each of the radar target and the stereo image target, and does not collate the radar target or the stereo image target with the previous fusion target. Therefore, the collision mitigation apparatus 11 differs from the collision mitigation apparatus 1 only in the process in the collision mitigation ECU, and includes a collision mitigation ECU 18 instead of the collision mitigation ECU 8 according to the first embodiment. In the second embodiment, the collision reduction ECU 18 corresponds to the determination means described in the claims.

  Similar to the collision mitigation ECU 8 according to the first embodiment, the collision mitigation ECU 18 is also an electronic control unit that performs overall control of the collision mitigation apparatus 11. The collision reduction ECU 18 is different from the collision reduction ECU 8 in radar target setting processing, stereo image target setting processing, and collation processing. Therefore, only each process will be described.

  The radar target setting process will be described. Similar to the first embodiment, the collision mitigation ECU 18 obtains a radar target from the radar information at regular time intervals. Further, the collision mitigation ECU 18 compares the previous radar target with the obtained radar target at regular time intervals. This collation is a collation method similar to the collation method between the previous fusion target and the current radar target in the first embodiment, and collation is performed based on distance, lateral position, and relative speed. At this time, each threshold value is set around the previous radar target instead of the previous fusion target, and it is determined whether or not the radar target is within the threshold value. When the collision reduction ECU 18 determines that there is similarity in the collation, the previous radar target is updated as the current radar target, and the current information is set. On the other hand, the collision reduction ECU 18 deletes the previous radar target when it is determined that there is no similarity in the collation. Further, the collision mitigation ECU 18 newly sets a radar target that has no similarity to the previous radar target as the current radar target.

  The stereo image target setting process will be described. Similar to the first embodiment, the collision reduction ECU 18 obtains a stereo image target from a stereo image at regular intervals. Further, the collision mitigation ECU 18 collates the previous stereo image with the obtained stereo image target at regular time intervals. This collation is a collation method similar to the collation method of the previous fusion target and the current stereo image target in the first embodiment, and the distance, horizontal position, height position, depth, width, height, relative Check by speed. At this time, each threshold value is set around the previous stereo image target instead of the previous fusion target, and it is determined whether or not the stereo image target is included in each threshold value. When the collision reduction ECU 18 determines that there is similarity in the collation, the previous stereo image target is updated as the current stereo image target, and the current information is set. On the other hand, when the collision reduction ECU 18 determines that there is no similarity in the collation, the previous stereo image target is deleted. Further, the collision reduction ECU 18 newly sets a stereo image target that has no similarity to the previous stereo image target as the current stereo image target.

  The verification process will be described. The collision reduction ECU 18 collates the current radar target with the current stereo image target at regular time intervals. This collation is a collation method similar to the collation method of the remaining current radar target and the current stereo image target in the first embodiment, and collation is performed by distance, lateral position, depth, lateral width, and relative speed. . When there are a plurality of targets to be collated in the collation (for example, when there are a plurality of radar targets this time), collation is performed for all combinations.

  With reference to FIG. 1, FIG. 2 and FIG. 5 to FIG. In particular, the flow of collation processing in the collision reduction ECU 18 will be described with reference to the flowchart of FIG. FIG. 9 is a flowchart showing a flow of collation processing according to the second embodiment. Here, only the radar target setting process, the stereo image target setting process, and the collation process in the collision reduction ECU 18 different from the operation in the collision reduction apparatus 1 will be described.

  The collision reduction ECU 18 receives a radar signal from the millimeter wave radar 2 and receives each image signal from the stereo camera 3.

  Then, the collision mitigation ECU 18 acquires a radar target based on radar information based on a radar signal at regular time intervals. Then, the collision mitigation ECU 18 collates the acquired radar target with the previous radar target in order to track the previous radar target at regular intervals. As a result of the collation, the collision reduction ECU 18 updates the previous radar target having similarity as the current radar target, sets the current information, and deletes the previous radar target having no similarity. Further, the collision reduction ECU 18 newly sets a radar target that has no similarity among the acquired radar targets as the current radar target. When the radar target has not been set last time, the collision reduction ECU 18 sets all the acquired radar targets as the current radar target.

  Further, the collision reduction ECU 18 acquires a stereo image target based on the left and right stereo images based on the respective image signals at regular time intervals. Then, the collision reduction ECU 18 collates the acquired stereo image target with the previous stereo image target in order to track the previous stereo image target at regular intervals. As a result of the collation, the collision reduction ECU 18 updates the previous stereo image target having similarity as the current stereo image target, sets the current information, and deletes the previous stereo image target having no similarity. . Further, the collision reduction ECU 18 newly sets a stereo image target having no similarity among the acquired stereo image targets as the current stereo image target. When the previous stereo image target has not been set, the collision reduction ECU 18 sets all the acquired stereo image targets as the current stereo image target.

  Before collating the radar target with the stereo target, the collision reduction ECU 18 determines whether or not the distance of the radar target is equal to or less than the distance reference T (S30). If it is determined in S30 that the distance is equal to or less than the distance reference T, the collision reduction ECU 18 sets A as a distance threshold (S31). On the other hand, when it is determined in S30 that the distance is longer than the distance reference T, the collision reduction ECU 18 sets B (> A) as a distance threshold (S32).

  Then, the collision reduction ECU 18 performs the following verification process at regular intervals. The collision reduction ECU 18 collates the radar target with the stereo image target based on the distance, the position information of the lateral position, the depth, the size information of the lateral width, and the relative speed (S33).

  The collision reduction ECU 18 determines whether there is similarity in the collation in S33 (S34). If it is determined in S34 that there is similarity, the collision reduction ECU 18 sets the current fusion target based on the similar radar target and the stereo image target, and the radar is used as information on the current fusion target. The distance and relative speed of the target are set, and the horizontal position, width, depth, height, and height position of the stereo image target are set (S35). The processes of S30 to S35 are performed for all combinations of all radar targets and all stereo image targets. By the processing so far, the collation processing of all radar targets and all stereo image targets is completed. If at least one of the radar target and the stereo image target is not set, the current matching process is not performed.

  This collision mitigation apparatus 11 also has the same effect as the collision mitigation apparatus 1 according to the first embodiment.

  As described in detail in the above embodiment, when the distance of the target detected by the radar is long, the position of the target by the image can be detected at a position away from the actual position due to the influence of the distance. There is sex. However, by configuring as in the present embodiment, it becomes easy to detect the target by the image and the target by the radar, and the object can be detected with high accuracy.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in this embodiment, the present invention is applied to a collision mitigation device mounted on a vehicle. However, the present invention can also be applied to other driving support devices such as an inter-vehicle distance control device and a following traveling device, and other devices such as a surrounding monitoring device. It can also be used as a single object detection device. In addition to the vehicle in front, other objects such as pedestrians and bicycles can be detected as detection targets. In addition to the vehicle, the vehicle can be mounted on a robot or the like.

  In this embodiment, the millimeter wave radar is used as the radar detection means, but other radars such as a laser radar may be used.

  In this embodiment, a stereo camera is used as the image detection unit. However, a camera other than the stereo camera may be used.

  In this embodiment, the configuration is such that the setting of the radar target based on the information by the millimeter wave radar and the setting of the stereo image target based on the stereo image by the stereo camera are performed by the collision mitigation ECU. The radar target may be set by a millimeter wave radar, or the stereo camera may be provided with an image processing unit, and the stereo image target may be set by the stereo camera.

  In this embodiment, the collation is performed using the size information such as the width and depth and the relative speed. However, the collation may be performed without using the relative speed, or the size information It is good also as a structure which collates without using all or one part.

  Further, in the present embodiment, it is configured that it is determined that there is similarity when all threshold conditions are satisfied by determination by a plurality of threshold values in each collation, but some threshold conditions among all threshold conditions It is good also as a structure which determines with there being similarity, when satisfy | filling.

  In the present embodiment, the distance threshold is changed only in one step based on the distance reference T. However, a plurality of distance references are provided, and the distance threshold is sequentially set in a plurality of steps according to the distance to the object. The threshold value may be increased stepwise as the distance of the object increases.

  In the present embodiment, the distance threshold is changed according to the distance to the object when the radar target and the stereo image target are collated, but the previous fusion target and the stereo image target are collated. Similarly, the threshold of the distance may be changed according to the distance to the object.

  In the second embodiment, the collision mitigation ECU uses a radar target tracking determination process based on information from a millimeter wave radar, a stereo image target tracking determination process based on a stereo image, and a radar target and a stereo image. Although it is configured to perform a collation process with a target, it is not necessary to perform all these processes in a collision reduction ECU, and a millimeter wave radar ECU for performing a radar target tracking determination process based on information by a millimeter wave radar An image ECU for performing a tracking determination process of a stereo image target based on a stereo image by a stereo camera may be provided separately from the collision reduction ECU. In this case, the target tracking determination processing is performed by the millimeter wave radar ECU and the image ECU, and the matching processing is performed by the collision reduction ECU. In such a configuration, it is suitable that the millimeter wave radar ECU is disposed between the millimeter wave radar and the collision mitigation ECU, and the image ECU is disposed between the stereo camera and the collision mitigation ECU.

It is a lineblock diagram of the collision mitigation device concerning this embodiment. It is explanatory drawing of the radar target concerning this Embodiment, a stereo image target, and a fusion target. It is explanatory drawing of the collation method with the last fusion target and radar target which concern on 1st Embodiment. It is explanatory drawing of the collation method with the last fusion target and stereo image target which concerns on 1st Embodiment. It is explanatory drawing of the collation method of the radar target and stereo image target which concerns on this Embodiment. It is a figure which shows the threshold value when an object exists in the vicinity in collation with the radar object and stereo image target concerning this Embodiment. It is a figure which shows the threshold value when an object exists in the distance in collation with the radar object and stereo image target which concern on this Embodiment. It is a flowchart which shows the flow of the collation process which concerns on 1st Embodiment. It is a flowchart which shows the flow of the collation process which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 ... Collision mitigation apparatus, 2 ... Millimeter wave radar, 3 ... Stereo camera, 4 ... Brake ECU, 5 ... Suspension control actuator, 6 ... Seat belt actuator, 7 ... Buzzer, 8, 18 ... Collision reduction ECU

Claims (2)

Radar detecting means for detecting an object by radar;
Image detection means for detecting an object from an image;
When the relationship between the position information of the object detected by the radar detection means and the position information of the object detected by the image detection means satisfies the determination criterion, the object detected by the radar detection means and the image detection means are detected. A judging means for judging that the selected object is the same object,
An object detection apparatus, wherein when the distance to an object is long, the determination criterion is changed so that it is easy to determine the same object. The determination unit is configured to detect the object detected by the radar detection unit and the image detection when the relationship between the position information of the object detected by the radar detection unit and the position information of the object detected by the image detection unit is a predetermined value or less. The object detected by the means is determined to be the same object,
The object detection apparatus according to claim 1, wherein the predetermined value is increased when the distance to the object is long.

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