JP3019684B2 - Car driving control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device for a motor vehicle, and more particularly to a vehicle drive control device which is useful when a preceding vehicle is photographed by a camera and tracking control is performed to track the preceding vehicle.

[0002]

2. Description of the Related Art In order to reduce the burden on a driver in driving an automobile, a constant-speed traveling device has been put to practical use, and an inter-vehicle distance control device has been developed.

[0003] The "constant speed traveling device"
It is also called "speed control" or "cruise control." In vehicles equipped with this device,
When the set switch is pressed, the vehicle keeps running at the set vehicle speed even when the accelerator pedal is released. The set vehicle speed can be changed by operating the control switch. This function is canceled when the driver steps on the brake, depresses the clutch, shifts the gear, or the like.

[0004] In order to ensure safety when the above-mentioned constant-speed traveling device is used, some devices have the following additional functions. That is, the distance from the preceding vehicle is detected by a laser radar or the like, and when the vehicle approaches the preceding vehicle abnormally, an alarm is issued to alert the driver or the gear shift stage is shifted from the fourth speed (overdrive) to the third speed. The engine decelerates due to overdrive off, which causes the engine to brake down and activate the engine brake.

On the other hand, in an automobile equipped with an "inter-vehicle distance control device", when a set switch is pressed, a target inter-vehicle distance is calculated from the vehicle speed of the own vehicle at that time, and the inter-vehicle distance with the preceding vehicle is detected. The vehicle is controlled by controlling the engine output and the brake so that the inter-vehicle distance between the vehicle and the vehicle becomes the target inter-vehicle distance. In this case, the inter-vehicle distance to the preceding vehicle is detected by performing image processing on an image captured by a camera, or by using a laser radar or the like.

However, in the former "constant-speed traveling device", when the driver catches up with a preceding vehicle having a low vehicle speed, the driver must perform a deceleration operation to release the constant-speed traveling control. Therefore, the operation is frequent on a congested road, which is rather troublesome and increases the risk.

On the other hand, in the latter "inter-vehicle distance control device",
Control cannot be performed when there is no preceding vehicle.

The inventor of the present application has developed a "vehicle travel control device" having both functions of a constant speed travel device and an inter-vehicle distance control device. Hereinafter, the "vehicle travel control device" will be described in detail. The "vehicle travel control device" is used when the vehicle travels on a highway and a dedicated motorway.

FIG. 4 shows an automobile provided with an "automotive travel control device". In the figure, 1 is a stereo camera,
2 is a laser radar, 3 is a throttle actuator, 4
Is a brake actuator, 5 is an operation switch / information display section, 6 is a controller, 7 is a vehicle speed sensor, 7a is a steering wheel angle sensor, 7b is a brake switch, 7c is a brake pedal switch, and 7d is an accelerator pedal switch.

The stereoscopic camera 1 is a front view shown in FIG.
As shown in the figure, two C that capture the scene in front of the car
The CD cameras 11 and 12 are arranged horizontally, and electronic components such as an image board and an aperture board are mounted in a body 13. The stereoscopic camera 1 is mounted near a room mirror in a vehicle cabin. Each camera 11, 1
The viewing angle in the horizontal plane of No. 2 is 23 degrees. Then, a video signal indicating an image captured by the cameras 11 and 12 is sent to the controller 6.

The images captured by the two cameras 11 and 12 are subjected to image processing by the image processing unit of the controller 6 to perform the following recognition. Recognition of the preceding car (preceding car). Recognition of a white line that indicates the lane on which the vehicle is traveling, among a plurality of lanes (lanes) on a highway. Recognition of the inter-vehicle distance between the preceding vehicle and the own vehicle.

The recognition of the preceding vehicle is performed, for example, as follows. That is, an area surrounded by a straight line in the vertical direction is extracted from the image, and an image which is symmetrical in the extracted area and whose position does not move much in the image to be captured one after another is recognized as a preceding vehicle. .

The above-described recognition of the white line indicating the traveling lane of the own vehicle is performed, for example, as follows. That is, as shown in FIG. 6 (a), the front road screen is fetched from the stereoscopic camera 1 and then, as shown in FIG. 6 (b), pixels along the four horizontal lines W1 to W4 are displayed. Then, a bright point is selected as a white line candidate, and as shown in FIG. 6C, a line segment obtained by interpolating the upper candidate point and the lower candidate point is extracted as a white line.

Recognition of the inter-vehicle distance between the preceding vehicle and the host vehicle is performed as follows. That is, from the two cameras 11 and 12 of the stereoscopic camera 1, FIG.
Two images are obtained as shown in FIG. The same image as the car image surrounded by the window on the right image is slightly shifted in the left image. Therefore, the position of the most matching image is obtained by shifting the right-side car image surrounded by the window by one pixel within the search area of the left-side image. At this time, as shown in FIG. 8, the focal length of the lenses of the cameras 11 and 12 is f, and the left and right cameras 11 and
Assuming that L is the distance between the 12 optical axes, P is the pixel pitch of the CCD, and n is the number of pixels obtained by shifting the right image until the left and right vehicle images match in FIGS. 7A and 7B. The distance (inter-vehicle distance) R to the car in question can be calculated by the following equation 1 based on the principle of triangulation.

[0015]

R = (f · L) / (n · P)

On the other hand, the laser radars 2 are arranged one by one at the right front end and at the left front end of the vehicle. The spread angle of the laser beam emitted from the laser radar 2 is 2 degrees. By measuring the time from when the laser beam is emitted from the laser radar 2 to when the laser beam reflected by the object returns to the laser radar 2 again, the distance to the object can be measured. it can.

Although the laser radar 2 can detect the presence or absence of an object at a long distance (100 m to several hundred m) in a short time, it cannot determine whether the object is an automobile.
On the other hand, in image processing using a camera, it is possible to accurately determine whether or not a target is an automobile, but it takes a long processing time until the determination is made. Therefore, the presence or absence of the object is detected by the laser radar 2, and when the presence of the object is confirmed, the roles are divided so as to detect the presence or absence of the car by performing image processing of the camera image by focusing on the detection area. Is also good. In this way, the preceding vehicle can be quickly and accurately detected.

Further, as shown in FIG. 9 when an automobile running on a highway is viewed from above, the laser beam 2a emitted from the laser radar 2 travels in a straight line while the camera 1
Since the field of view 1a is 23 degrees, when another vehicle suddenly breaks in front of the own vehicle, the laser beam 2a first strikes and reflects on the other vehicle (the other vehicle interrupted at this time is the camera 1). Not in the field of view 1a). Therefore, the detection of the interrupted vehicle is handled by the laser radar 2 which can detect the interrupted vehicle first and has a quick response. In FIG. 9, 8, 8a and 8b are white lines. The continuous white line 8 is at the end of the highway, and the dotted white lines 8a and 8b are at the positions separating the lanes.

When the throttle actuator 3 is operated by a command from the controller 6 to increase the throttle opening, the engine speed increases and the vehicle speed increases. Conversely, as the opening of the throttle is reduced, the engine brake is activated and decelerates. Tracking running control, which will be described later, is executed by adjusting the throttle opening. When the brake actuator 4 is actuated by the command of the controller 6 to apply a brake, the vehicle decelerates rapidly. This rapid deceleration occurs when another vehicle interrupts immediately before the own vehicle, or when performing a brake control described later, that is, when the own vehicle traveling at a high speed approaches the preceding vehicle traveling at a low speed, and This is performed when the distance becomes shorter than the safe inter-vehicle distance.
In the present system, the vehicle is suddenly decelerated by the command of the controller 6, but does not stop suddenly, but is stopped only when the driver depresses the brake pedal.

Next, an outline of traveling control performed mainly by the controller 6 will be described with reference to FIG. Controller 6
The image processing unit 61 performs image processing on an image captured by the stereoscopic camera 1, the vehicle recognizing unit 61a recognizes an image of an automobile from a scene in front, and the lane recognizing unit 61b drives the own vehicle. The white line indicating the lane is recognized, and the following distance recognition unit 61c recognizes the following distance between the preceding vehicle and the own vehicle. The target tracked vehicle recognizing unit 62 recognizes the vehicle as the target tracked vehicle when there is a vehicle ahead of the lane in which the vehicle is traveling.

When the target tracked vehicle recognition unit 62 recognizes the target tracked vehicle, the setting command unit 63 controls the tracking travel. In other words, the setting command unit 63 is the inter-vehicle distance recognition unit 61c.
Alternatively, the inter-vehicle distance to the target tracking vehicle is obtained by using the laser radar 2, and the target inter-vehicle distance is obtained by multiplying the vehicle speed of the own vehicle obtained from the vehicle speed sensor 7 by a set time (for example, 2 seconds). Then, the throttle actuator 3 is operated to control the engine speed (∽throttle opening) so that the actual inter-vehicle distance D becomes equal to the target inter-vehicle distance D ₀ . In this way, in a state of taking the target inter-vehicle distance D ₀ corresponding to the vehicle speed, while tracking the target tracking vehicle host vehicle is gradually travels. Therefore, when the target tracked vehicle is traveling at high speed (for example, 120 km / h), the target inter-vehicle distance D ₀ is long (for example, 66.7 m), and the own vehicle is traveling at high speed (for example, 120 km / h) while tracking the target tracked vehicle. h) Yes. Also, the target tracking vehicle runs at low speed (for example, 60 km / h).
When you are in, the target inter-vehicle distance D ₀ is shortened (e.g. 33.3M), the vehicle is low speeds while tracking the target tracking vehicle (e.g. 60 km / h).

During tracking control, the preceding vehicle exists at a position closer than the safe inter-vehicle distance (determined by the relative speed between the own vehicle and the running vehicle and the own vehicle speed as described later). Is detected, the process shifts to deceleration running control.

The "vehicle travel control device" performs constant-speed travel control, vehicle speed holding control, and the like in addition to the above-described tracking travel control and deceleration travel control, but a description thereof will be omitted.

As described above, in the vehicle equipped with the "vehicle travel control device", the vehicle travels at a constant speed at the set vehicle speed when there is no preceding vehicle, while maintaining the target inter-vehicle distance when the preceding vehicle exists. It tracks the preceding vehicle, and performs deceleration control when there is an interruption or when the high-speed vehicle catches up with the low-speed preceding vehicle. If this "vehicle travel control device" is used when traveling on the main line of a highway, the driver can travel simply by operating the steering wheel, and so-called easy drive can be realized. In addition, safety can be expected to be improved, even if a slight look-aside or sneaking can be avoided, because it is possible to avoid the danger of abnormally approaching or crashing into the vehicle ahead.

[0025]

However, in the above-mentioned "vehicle control device", the iris is controlled so that the exposure of the stereoscopic camera 1 matches the average brightness of the entire screen. As shown in (an example of an image taken by the stereoscopic camera 1), if the preceding vehicle 26 enters the tunnel 28 while the own vehicle is still traveling in front of the tunnel 28, the preceding vehicle 26 is included. Since the image in the tunnel 28 becomes too dark, even if the image processing is performed, the preceding vehicle 26 cannot be recognized and is lost.
Conversely, if the preceding vehicle 26 exits the tunnel 28 while the own vehicle is still traveling in the tunnel 28, the preceding vehicle 26
Also, since the surrounding image becomes too bright, the preceding vehicle 26 cannot be recognized and is lost.

According to the present invention, in consideration of the above-mentioned "vehicle travel control device", the preceding vehicle is lost even when there is a difference in brightness between the area occupied by the preceding vehicle and its surroundings, such as the entrance of a tunnel. It is an object of the present invention to provide a travel control device for an automobile that can track without a vehicle.

[0027]

Configuration of the present invention to achieve the above object, according to an aspect of the front of the vehicle captured by the camera travels an image subjected to image processing to the own vehicle in the same lane at this time prior Recognize the car, in a vehicle travel control device that performs tracking travel control to track the preceding vehicle while maintaining a predetermined inter-vehicle distance with the preceding vehicle, when the preceding vehicle is recognized by the image processing, An iris control area setting unit for setting an area in the image occupied by the preceding vehicle as an iris control area, and an image for extracting image data in the iris control area from the entire image data representing the brightness of the image A data extraction unit, an iris value calculation unit for calculating an iris value for controlling the iris of the camera based on the image data in the iris control area, and the iris value It includes an iris control unit and an output unit for outputting to the driving unit for driving the La iris, the A
In the iris control area setting section, the iris control
Your area is memorized, and the preceding vehicle is
If it cannot be recognized, the previously set
Iris control area as iris control area
It is characterized by setting .

[0028]

[0029]

In accordance with the above Ki構 configuration of the present invention, the iris is controlled preceding vehicle by the brightness of the iris control area is occupied ordinating region, the optimum exposure can be obtained to recognize the results preceding vehicle . Therefore, even when the area occupied by the preceding vehicle is darker or brighter than its surroundings, such as at the entrance of a tunnel, the preceding vehicle can be recognized without losing sight of the preceding vehicle.
Furthermore, the area occupied by the preceding vehicle is sharper than its surroundings.
It becomes dark or bright, and at that moment it can not recognize the preceding vehicle
The iris control area set last time is
It is used as it is, and depending on the brightness of this area, the iris
Controlled. Recognize the preceding vehicle compared to the speed of the preceding vehicle
The image processing cycle is short enough for the preceding vehicle
The occupied area hardly moves. So above
By setting the iris control area to
In such a case, the optimal exposure for capturing
Can be

[0030]

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the same parts as those of the "vehicle travel control device" described in the section of [Prior Art] are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 1 is a system configuration diagram showing a system related to a point of the present invention extracted from a travel control device for an automobile according to an embodiment of the present invention. The configuration other than that shown in the figure is the same as the “vehicle travel control device” described in the section of “Prior Art”.

As shown in FIG. 1, the system includes a stereo vision camera 1, a vehicle recognizing unit 6 provided in a controller 6.
1 a, an iris control unit 20, and an iris drive unit 25 built in the stereoscopic camera 1. The outline of the operation of this system is as follows.

The image of the road ahead of the own vehicle taken by the stereoscopic camera 1 is taken into the vehicle recognizing section 61a, where image processing is performed. Recognizes the preceding vehicle traveling on the result the vehicle and the same lane, the iris control unit 20, the iris value E _x for the preceding vehicle of the image controls the iris based on the brightness of the occupied coordinating region as well as operation, and outputs the iris value E _x to the iris driving section 25 constituted by a motor or the like. The iris drive unit 25 receives the iris value E _x, to drive the iris based on the iris value E _x. In this way, an optimal exposure of the stereoscopic camera 1 for imaging the preceding vehicle and recognizing it can be obtained. Hereinafter, these will be described in detail with reference to FIG.

FIG. 2 is a block diagram showing details of the iris control unit 20. As shown in FIG.
0 has an iris control area setting unit 21, an image data extraction unit 22, an iris value calculation unit 23, and an output unit 24.

Of these, the iris control area setting unit 2
When the vehicle recognizing unit 61a recognizes the preceding vehicle 26, the vehicle 1 sets an iris control area, which is an area occupied by the preceding vehicle 26, in the image 28. Specifically, a minimum rectangular area surrounding the preceding vehicle 26 is obtained, and this is defined as an iris control area 27.

The image data extraction unit 22 is provided with an iris control
Iris control area 27 is set by rear setting section 21
In the image data representing the brightness of all the pixels of the image 28
The image data of the pixels existing in the iris control area 27 is
Data, ie, from row i to row i + p and from column j to column j + q
Image data a of all pixels within the range_i,_j, A_i,
_{j + 1}, ..., a_{i + p},_{j + q}And extract these
Output to the iris value calculator 23. Note that such images
The data is obtained by processing the image 28 in the vehicle recognition unit 61a.
Ask when you work.

The iris value calculator 23 extracts the image data.
Image data a extracted by the unit 22_i,_j, A_i,_{j + 1},
…, A_{i + p},_{j + q}Enter the iris based on these
Value E _xIs calculated. For example, as shown in the following equation 2,
Data a_i,_j, A_i,_{j + 1}, ..., a_{i + p},_{j + q}The average of
And the appropriate exposure value E_oAnd the iris value E _x
And

[0039]

(Equation 2)

The output unit 24 outputs the calculated iris value E _x iris value calculation section 23 to the iris driving section 25.

As described above, according to the above embodiment, the iris is determined based on the image data representing the brightness in the area occupied by the preceding vehicle 26, that is, in the iris control area, of the image captured by the stereoscopic camera 1. Controlled. Therefore, as shown in FIG. 3 (an example of an image captured by the stereoscopic camera 1), even when the preceding vehicle 26 enters the tunnel 28 while the own vehicle is still running in front of the tunnel 28, The iris is controlled by the image data representing the brightness in the iris control area 27 at the time, and the exposure of the stereoscopic camera 1 becomes optimal for capturing the image of the preceding vehicle 26. There is no. At this time, the image around the tunnel 28 (indicated by the dotted line in the figure) becomes completely white due to overexposure,
There is no particular problem in recognizing the preceding vehicle 26.

Even if the preceding vehicle 26 exits the tunnel 28 while the own vehicle is still traveling in the tunnel 28, the iris is controlled in the same manner as described above.
The vehicle does not lose sight of the preceding vehicle 26. At this time, the image in the tunnel 28 becomes black due to insufficient exposure, but there is no particular problem similarly to the above.

Actually, the current image is an image obtained by exposure obtained by iris control based on an iris value obtained from a previously taken image. Therefore, instead of gradually darkening as you enter the tunnel from the entrance to the back, or gradually becoming brighter near the exit of the tunnel toward the exit of the tunnel, it suddenly darkens at the entrance of the tunnel or brightens suddenly at the exit of the tunnel. In such a case, there is a possibility that the preceding vehicle cannot be recognized from an image taken at the moment of entering the tunnel entrance or at the moment of exiting the tunnel exit. If the preceding vehicle cannot be recognized, the iris control area is not set, so that the appropriate iris control is not performed, and if the appropriate iris control is not performed, the preceding vehicle cannot be recognized. .

Therefore, the iris control area setting section 21 stores the previously set iris control area, and when the preceding vehicle cannot be recognized from the image taken this time as described above, the previously set iris control area is used as it is. Then, it is set as the current iris control area. As a result, the image data extraction unit 22 extracts the image data of the pixels existing in the same area as the previously set iris control area from the image data of all the pixels of the current image, and the iris calculation unit 23 An iris value _Ex is calculated based on the obtained image data.

Since the period of the image processing for recognizing the preceding vehicle is 0.1 second or less, the area in the image occupied by the preceding vehicle hardly moves during this period. Since the relative speed of the preceding vehicle to the own vehicle is low because the vehicle is following the preceding vehicle, there is little movement in the traveling direction (up and down direction of the image), and there is almost no movement in the left and right direction within 0.1 sec or less. It is because it is considered. Therefore, when the iris control area setting unit 21 operates as described above, even when the preceding vehicle cannot be recognized for a moment as described above, the iris control area setting unit 21 is optimal for appropriately controlling the iris and imaging the preceding vehicle. Exposure can be obtained.

[0046]

According to the present invention, as described above in detail with the embodiments, only the preceding vehicle occupies the same position as when entering the tunnel or exiting the tunnel first. Even in the case where there is a difference in lightness and darkness between the area to be exposed and the surrounding area, the exposure of the camera is optimally controlled. Therefore, even in such a case, the preceding vehicle is not lost, and more reliable tracking control can be performed.

[0047]

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a system related to a point of the present application extracted from a travel control device for an automobile according to an embodiment of the present invention.

FIG. 2 is a block diagram showing details of an iris control unit 20;

FIG. 3 is an explanatory diagram showing an example of an image captured by the stereoscopic camera 1;

FIG. 4 is a configuration diagram showing an automobile provided with an automobile traveling control device.

FIG. 5 is a front view showing a stereoscopic camera.

FIG. 6 is an explanatory diagram showing a method of detecting a white line by image processing.

FIG. 7 is an explanatory diagram showing a method for detecting an inter-vehicle distance by image processing.

FIG. 8 is a principle diagram for calculating an inter-vehicle distance based on the principle of triangulation.

FIG. 9 is a plan view showing an automobile running on a highway.

FIG. 10 is a block diagram showing a controller.

FIG. 11 is an explanatory diagram showing an example of an image captured by the stereoscopic camera 1.

[Explanation of symbols]

 Reference Signs List 1 stereo vision camera 1a visual field 11,12 CCD camera 13 body 2 laser radar 2a laser beam 20 iris control unit 21 iris control area setting unit 22 image data extraction unit 23 iris value calculation unit 24 output unit 25 iris drive unit 26 preceding vehicle 27 Iris control area 28 Tunnel 3 Throttle actuator 4 Brake actuator 5 Operation switch / information display unit 6 Controller 61 Image processing unit 61a Vehicle recognition unit 61b Lane recognition unit 61c Inter-vehicle distance recognition unit 62 Target tracking vehicle recognition unit 63 Setting command unit 7 Vehicle speed sensor 7a Handle angle sensor 7b Brake switch 7c Brake pedal switch 7d Accelerator pedal switch 8, 8a, 8b White line

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI H04N 5/235 G06F 15/62 380 15/64 340B (56) References JP-A-64-66712 (JP, A) 5-236337 (JP, A) JP-A-5-219431 (JP, A) JP-A-2-126246 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 31/00 B60R 21/00 620 G05D 1/02 G08G 1/16 G06T 1/00

Claims (1)

(57) [Claims] 1. An image of the front of an own vehicle is taken by a camera, and the image at this time is image-processed to recognize a preceding vehicle traveling in the same lane as the own vehicle, and a predetermined inter-vehicle distance is set between the preceding vehicle and the preceding vehicle. In a vehicle travel control device that performs tracking travel control for tracking the preceding vehicle while holding the preceding vehicle, when the preceding vehicle is recognized by the image processing, an area in the image occupied by the preceding vehicle is controlled as an iris control area. An iris control area setting unit to be set as: an image data extracting unit that extracts image data in the iris control area from the entire image data representing the brightness of the image; and An iris value calculation unit that calculates an iris value for controlling an iris of the camera, and an output unit that outputs the iris value to a driving unit that drives the iris of the camera. Includes an iris control unit having, in the iris control area setting unit, the eye previously set
The squirrel control area is stored in memory.
If the vehicle cannot be recognized,
Iris control area as it is
A travel control device for a vehicle, wherein the travel control device is set as: