JPH07333342A - Inter-vehicle distance measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] The inter-vehicle distance is measured only for the preceding vehicle in the same lane as the host vehicle. A radar distance measuring means 1 for measuring a distance and a direction to a vehicle in front by a scanning radar mounted on the vehicle,
A video camera 2 mounted on the vehicle for capturing a road image in front of the vehicle, and a lane marker drawn on the road surface by using the road image captured from the video camera 2 to detect a traveling lane in which the vehicle is traveling. Running lane detection means 3
And a forward vehicle determining means 4 for determining whether or not the forward vehicle detected by the radar distance measuring means 1 is in the same lane as the own vehicle by using the lane detection result detected by the traveling lane detecting means 3. The inter-vehicle distance is measured only for the preceding vehicle in the same lane as the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance measuring device for measuring a distance to a vehicle ahead while a vehicle is traveling.

[0002]

2. Description of the Related Art Conventionally, an alarm device using a radar has been proposed for the purpose of preventing a rear-end collision accident due to a drowsy driving or a side-looking driving on a highway. As an inter-vehicle distance measuring device of this type, Japanese Patent Laid-Open No. 5-290298
As described in the publication, a plurality of beams are used to measure the distance for each area and an alarm is output. Also,
The measured distance is monitored and the curved road reflector is recognized based on the change in the distance to prevent the false alarm from being output.

[0003]

However, such an inter-vehicle distance measuring device has a problem that it is not possible to accurately determine whether or not the detected front vehicle is a vehicle in a running lane.

The present invention solves the above problems and provides a vehicle-to-vehicle distance measuring device that determines whether or not a vehicle ahead is in the same lane as the vehicle using road images. The purpose of 1.

A second object of the present invention is to provide an inter-vehicle distance measuring device for determining the possibility of collision only with respect to a forward vehicle existing in a traveling lane. Further, a third object is an inter-vehicle distance measuring device which prompts the driver to give an alarm only when there is a possibility of collision with a forward vehicle existing in a traveling lane.

[0006]

In order to achieve the above object, an inter-vehicle distance measuring device of the present invention comprises a radar distance measuring means for measuring a distance and a direction to a vehicle ahead by a scanning radar mounted on the vehicle. A video camera mounted on the vehicle to capture a road image in front of the vehicle, and a lane marker drawn on the road surface using the road image captured from the video camera to detect the lane in which the vehicle is traveling Front vehicle determining means for determining whether or not the front vehicle detected by the radar distance measuring means is in the same lane as the own vehicle using the lane detecting means and the lane detection result detected by the traveling lane detecting means. The vehicle-to-vehicle distance is measured only for the preceding vehicle in the same lane as the own vehicle.

Further, the inter-vehicle distance measuring apparatus of the present invention is a radar distance measuring means for measuring the distance and direction to a vehicle ahead by a scanning radar mounted on the vehicle, and a road image in front of the vehicle mounted on the vehicle. Video camera, a driving lane detecting means for detecting a lane in which the vehicle is traveling by detecting a lane marker drawn on the road surface by using a road image captured from the video camera, and the traveling lane detecting means. A forward vehicle determining hand for determining whether or not the forward vehicle detected by the radar distance measuring means is in the same lane as the own vehicle using the lane detection result, and a speed detecting means for detecting the speed of the own vehicle And the speed of the host vehicle detected by the speed detection means and the inter-vehicle distance to the front vehicle determined to be present in the same lane by the front vehicle determination means, With a collision determination means for determining the possibility of a rear-end collision using the relative speed calculated from the time-series change of the inter-distance, the possibility of a collision is determined only for the front vehicle existing in the same lane. is there.

Further, an alarm means for urging an alarm when the collision judging means judges that there is a possibility of collision is added, and the vehicle is driven only when there is a possibility of collision with a vehicle in front in the same lane. It is designed to prompt people to give an alarm.

[0009]

According to the present invention, with the above structure, it is possible to accurately determine whether or not the detected front vehicle is a vehicle in a running lane, and only when the front vehicle in the same lane as the own vehicle is collided. The possibility can be determined, and furthermore, the driver can be alerted only when there is a possibility of a collision with a preceding vehicle present in the lane in which the vehicle is running.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inter-vehicle distance measuring apparatus according to a first embodiment of the present invention will be described below with reference to the block diagram showing the basic structure of FIG. In FIG. 1, the radar distance measuring means 1 detects the distance and direction to the vehicle in front. The video camera 2 captures a road ahead of the vehicle to obtain a road image, and the traveling lane detection means 3 detects a traveling lane using the road image obtained by the video camera 2. The forward vehicle determining means 4 is a vehicle in the same lane as the own vehicle using the distance and direction to the forward vehicle detected by the radar distance measuring means 1 and the position of the lane marker detected by the traveling lane detecting means. It is to determine whether or not.

The operation of the above configuration will be described with reference to the operation flowchart of FIG. First, when the apparatus is started, in step 11, the scanning laser radar calculates the distance to the object for each scan angle. As shown in FIG. 3, the scanning laser radar is attached to the front of the vehicle, scans the area of a predetermined divergence angle δ with a predetermined laser beam, and after the laser beam is transmitted, it is reflected by an object and returned. The distance to the object is calculated for each scan angle from the time until the object comes.
The calculated distance for each angle is the front vehicle determination processing step 1
Sent to 8.

At the same time when the apparatus is started, the road image ahead of the vehicle is captured from the video camera 2 in step 12. As shown in FIG. 6A, the CCD camera is attached so that its optical axis is downward by θ from the traveling direction of the vehicle. FIG. 4 shows a road image captured by the video camera 2.

Next, in step 13, edge extraction processing in the traveling lane detection means 3 is performed, and edge components are extracted from the captured road image. Edge extraction is s
This can be done using an edge extraction filter such as an obel filter.

Next, in step 14, a threshold value setting process in the traveling lane detecting means 3 is performed. The threshold value is set using the edge strength so that the edge component indicating the white line outline can be extracted. For example, the threshold value can be set as a sum of c times the maximum edge strength value and (1-c) times the average edge strength value for a preset scanning line, where c is a constant satisfying 0 <c <1.

Next, in step 15, white line contour extraction processing in the traveling lane detection means 3 is performed. As shown in FIG. 5, the white line is extracted by searching for pixels exceeding the threshold value set in step 14 from the center of the edge image toward the outside of each of the left and right sides, and first extracting the pixel exceeding the threshold value as a white line outline. It can be carried out.

Next, in step 16, the linear approximation processing in the traveling lane detecting means 3 is performed. The straight line approximation process is, for example, Hough, which is one of straight line detection algorithms.
Techniques such as transformation and least squares can be applied to the white line contours obtained in step 15. FIG. 5 shows a white line linearly approximated. Further, the approximation processing of the outline of the white line may be performed by a polygonal line or a quadratic curve.

Next, in step 17, the coordinate system conversion processing in the forward vehicle determination means 4 is performed. In the coordinate system conversion processing, the angle and distance to the vehicle ahead calculated in step 11 are converted into the image coordinate system obtained in step 12. Here, the relational expression between the world coordinate system and the image coordinate system is shown below. Figure 6
The world coordinate system and the image coordinate system as shown in (a) and (b) are used. The world coordinate system (X, Y, Z) is a coordinate system fixed with respect to the vehicle, and the origin O (0, 0, 0) is set on the ground surface directly below the video camera, and the left hand whose traveling direction is Z is set. Use the coordinate system. Further, it is assumed that the x axis of the image coordinate system (x, y) is parallel to the X axis of the world coordinate system, and the y axis is inclined with respect to the Y axis by an angle θ. The origin o (0, 0) of the image coordinate system is set at the center of the bottom of the image. When the distance of the camera from the ground is H and the focal length of the camera is F, the relationship between the pixel (x, y) and the world coordinate system (X, Y, Z) is as follows.

[0018]

[Equation 1]

[0019]

[Equation 2]

Y = H (3) FIG. 7 shows X and Z coordinates calculated from the distance and direction calculated in step 11 and converted into an image coordinate system with Y = 0. The X coordinate of the camera and the X coordinate of the laser radar are installed at the same position.

Next, in step 18, the forward vehicle determination processing in the forward vehicle determination means 4 is performed. In the front vehicle determination process, it is checked whether or not the distance data of the front vehicle converted into the image coordinate system in step 17 exists between the left and right white lines that are linearly approximated in step 16. If it exists between the left and right white lines, it can be determined that it is a preceding vehicle in the same lane.

As described above, according to the present embodiment, it is accurately determined whether or not the detected forward vehicle is a vehicle in the traveling lane, and the inter-vehicle distance is set only for the preceding vehicle in the same lane as the own vehicle. It can be measured.

Next, an inter-vehicle distance measuring apparatus according to a second embodiment of the present invention, that is, an inter-vehicle distance measuring apparatus characterized in that the possibility of collision is determined only with respect to a front vehicle existing in the same lane as shown in FIG. Will be described with reference to the block diagram of FIG. In FIG. 8, the radar distance measuring means 1 detects the distance and direction to the vehicle in front. The video camera 2 captures a road ahead of the vehicle to obtain a road image, and the traveling lane detection means 3 detects a traveling lane using the road image obtained by the video camera 2. The front vehicle determination means 4 is a vehicle in the same lane as the own vehicle using the distance and direction to the front vehicle detected by the radar distance measuring means 1 and the position of the lane marker detected by the traveling lane detection means. It is to determine whether or not. The speed detecting means 5 takes in the vehicle speed of the own vehicle, and the collision judging means 6 determines the distance to the preceding vehicle and the distance of the own vehicle with respect to the vehicle judged to be the preceding vehicle in the same lane by the front vehicle judging means 4. The possibility of a collision is determined from the vehicle speed and the relative speed between the preceding vehicle and the host vehicle.

The operation of the above configuration will be described with reference to the operation flowchart of FIG. First, when the device is started, as in the first embodiment, the distance to the vehicle in front is measured for each scan angle in step 11, and step 12
The road image is captured with. After that, the same processing is performed up to step 18. Further, when the device is started, the speed detection processing of the own vehicle is performed by the speed detection means in step 19.

Next, in step 20, the collision determination means 6
Collision determination processing is performed. The collision is determined by determining the distance to the vehicle determined to be the preceding vehicle in the same lane in step 18, the own vehicle speed input in step 19, and the preceding several times of preceding vehicles stored in the collision determination means 6. When the relative velocity calculated from the history of the distance data is used, it is determined that there is a possibility of collision when the formula (4) is not satisfied.
The relative speed is positive when approaching the preceding vehicle.

(Distance between vehicles)> a × (relative speed) + b × (vehicle speed) + c (4) Here, the constants a, b, and c are set according to the vehicle type, performance, etc. of the vehicle. As described above, according to the present embodiment, it is possible to determine the possibility of a collision with respect to a front vehicle in the same lane as the own vehicle.

Next, an inter-vehicle distance measuring apparatus according to a third embodiment of the present invention, that is, a driver is urged to give an alarm only when there is a possibility of a collision with a vehicle in front in the same lane. An inter-vehicle distance measuring device to be described will be described with reference to the block diagram of FIG. In FIG.
The radar distance measuring means 1 detects the distance and direction to the vehicle ahead. The video camera 2 captures a road image in front of the vehicle and obtains a road image.
Detects a running lane using a road image obtained by the video camera 2. The front vehicle determination means 4 is a vehicle in the same lane as the own vehicle using the distance and direction to the front vehicle detected by the radar distance measuring means 1 and the position of the lane marker detected by the traveling lane detection means. It is to determine whether or not. Speed detection means 5
Represents the vehicle speed of the host vehicle, and the collision determination means 6
Is a possibility of collision with a vehicle determined to be a preceding vehicle in the same lane by the front vehicle determination means 4 based on the distance to the preceding vehicle, the vehicle speed of the own vehicle, and the relative speed between the preceding vehicle and the own vehicle. It is a thing. The warning means 7 prompts the driver to warn when the collision determination means 6 determines that there is a possibility of a collision.

The operation of the above configuration will be described with reference to the operation flowchart of FIG. First, when the device is started, the processes up to step 20 are performed as in the second embodiment, and the possibility of collision with the preceding vehicle in the same lane is determined.

Next, in step 21, alarm processing is performed by the alarm means 7. The warning process prompts the driver to give a warning by voice when it is determined in step 20 that there is a possibility of collision with the preceding vehicle.

As described above, according to the present embodiment, it is possible to prompt the driver to give an alarm only when there is a possibility of a collision with a preceding vehicle in the same lane as the own vehicle.

[0031]

As described above, according to the present invention, it is possible to accurately determine whether or not the preceding vehicle is in the traveling lane and measure the inter-vehicle distance only for the preceding vehicle in the same lane. It is possible.

Further, it is possible to determine the possibility of collision only with respect to a vehicle ahead in the same lane as the own vehicle.
Further, it is possible to prompt the driver to give an alarm only when there is a possibility of collision with a preceding vehicle existing in the traveling lane.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of an inter-vehicle distance measuring device according to a first embodiment of the present invention.

FIG. 2 is an operation flowchart in the inter-vehicle distance measuring device according to the first embodiment.

FIG. 3 is a diagram for explaining a scanning laser radar in the inter-vehicle distance measuring apparatus of the first embodiment.

FIG. 4 is a diagram showing a road image captured from a video camera in the inter-vehicle distance measuring apparatus according to the first embodiment.

FIG. 5 is a diagram illustrating white line contour extraction processing in the vehicle distance measuring apparatus according to the first embodiment.

FIG. 6 is a diagram for explaining coordinate system conversion processing in the inter-vehicle distance measuring apparatus according to the first embodiment.

FIG. 7 is a diagram showing a distance image obtained by converting the coordinate system in the vehicle-to-vehicle distance measuring apparatus according to the first embodiment.

FIG. 8 is a block diagram showing a basic configuration of an inter-vehicle distance measuring device according to a second embodiment of the present invention.

FIG. 9 is an operation flowchart of the inter-vehicle distance measuring device according to the second embodiment.

FIG. 10 is a block diagram showing a basic configuration of an inter-vehicle distance measuring device according to a third embodiment of the present invention.

FIG. 11 is an operation flowchart of the inter-vehicle distance measuring device according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radar distance measuring means 2 Video camera 3 Driving lane detecting means 4 Front vehicle judging means 5 Speed detecting means 6 Collision judging means 7 Warning means

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G08G 1/16 E C H04N 7/18 C

Claims (3)

[Claims] 1. A radar distance measuring means for measuring a distance and a direction to a vehicle ahead by a scanning radar mounted on the vehicle, a video camera mounted on the vehicle for capturing a road image ahead of the vehicle, and the video camera. A traveling lane detecting means for detecting a lane marker drawn on the road surface using the captured road image to detect a lane in which the vehicle is traveling, and the radar using the lane detection result detected by the traveling lane detecting means. A front vehicle determination means for determining whether or not the front vehicle detected by the distance measuring means is in the same lane as the own vehicle is provided, and the inter-vehicle distance is measured only for the preceding vehicle in the same lane as the own vehicle. An inter-vehicle distance measuring device characterized in that 2. A radar distance measuring means for measuring a distance and a direction to a vehicle ahead by a scanning radar mounted on the vehicle, a video camera mounted on the vehicle for capturing a road image ahead of the vehicle, and the video camera. The traveling lane detection means for detecting a lane marker drawn on the road surface using the captured road image to detect a lane in which the vehicle is traveling, and the radar using the lane detection result detected by the traveling lane detection means. A front vehicle determining hand for determining whether or not the front vehicle detected by the distance measuring means exists in the same lane as the own vehicle, and a speed detecting means for detecting the speed of the own vehicle,
A rear-end collision is performed using the speed of the own vehicle detected by the speed detection means, the inter-vehicle distance to the front vehicle determined to be in the same lane by the front vehicle determination means, and the relative speed calculated from the time-series change of the inter-vehicle distance. An inter-vehicle distance measuring device, comprising: a collision determining means for determining the possibility of the collision, and determining the possibility of the collision only for a vehicle in front in the same lane. 3. The inter-vehicle distance measuring device according to claim 2, further comprising warning means for urging a warning when the collision judging means judges that there is a possibility of a collision, and a front vehicle existing in the same lane. An inter-vehicle distance measuring device characterized in that a driver is alerted when there is a possibility of a collision.