Television – Special applications – Navigation
Reexamination Certificate
1997-12-22
2001-09-04
Britton, Howard (Department: 2713)
Television
Special applications
Navigation
C382S104000, 36
Reexamination Certificate
active
06285393
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an object recognition apparatus and method performing recognition of objects on and around a road, on which a vehicle is traveling, on the basis of images picked up by an on-vehicle camera, and to a camera attitude parameter generating apparatus and method producing camera attitude parameters which represent the attitude of the on-vehicle camera with respect to the road, and are used for the recognition of objects.
2. Description of Related Art
Various techniques have been proposed to pick up images ahead of or behind a vehicle by an on-vehicle camera, and to recognize objects in the images. For example, if the foregoing vehicles are recognized by processing the foregoing images of the vehicle, which are acquired by the on-vehicle camera, the results can be used in an automatic operation of the vehicle, thereby preventing an accident. Specifically, if other vehicles abnormally approach the vehicle, an accident can be prevented by automatic steering or brakes. Furthermore, if road signs can be recognized, the information associated with the road signs can be used in a navigation apparatus for directing a course of the vehicle.
When recognizing an object in an image acquired by an on-vehicle camera, the position of the object in the image changes every moment. A high efficiency recognition of such object which moves in an image from moment to moment requires accurate camera attitude parameters which represent the attitude of the on-vehicle camera with respect to the road, that is, to a quiescent coordinate system. In other words, the behavior of an object in an image can be estimated on the basis of the accurate camera attitude parameters. Using the estimation results makes it possible to cut off an image portion, which would include the object, from the image acquired, and to carry out an image recognition processing of the cut off image portion, which will improve the image processing efficiency. Here, the camera attitude parameters include the yaw angle, the roll angle and the pitch angle of the on-vehicle camera with respect to a road (a quiescent coordinate system) and a traverse deviation distance of the on-vehicle camera from a reference line parallel to the road.
The camera attitude parameters may be changed by variables inherent to the vehicle such as acceleration, speed, bearing of the vehicle. Many of these variables can be provided by a position detection processing unit and an anti-lock brake unit, which are mounted on the vehicle. The position detection processing unit has a basic function of detecting the current position of the vehicle on the basis of the mileage and bearing of the vehicle, and displaying them on a display unit with a road map. The anti-lock brake unit has a g-sensor detecting the acceleration (including deceleration) of the vehicle, and a wheel speed sensor detecting the rotational speed of a wheel, and controls the brake pressure on the basis of the detection results, thereby preventing the wheels from locking, and achieving an optimum braking.
In a conventional system, however, these data handled by the position detection processing unit or the anti-lock brake unit are not utilized to obtain the camera attitude parameters, and hence, the accuracy and efficiency of obtaining the camera attitude parameters are insufficient.
Since various objects such as vehicles, pedestrians, road signs will appear or disappear in a scene picked up by the on-vehicle camera, an object that comes into a scene of the on-vehicle camera at a particular processing period must be identified in the scene at the next processing period. To achieve this, a tracking recognition of an object must be implemented by taking account of the position of the object, the change in the position, a positional detection error, identification of a still or moving state, patterns of the object, or the like. The tracking recognition of an object requires a quick processing because it is carried out by successively acquiring images by the on-vehicle camera while the vehicle is traveling.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a camera attitude parameter generating apparatus and method which can produce camera attitude parameters with high accuracy and at high efficiency by using information provided by a position detection processing unit or an anti-lock brake unit.
It is another object of the present invention to provide an object recognition apparatus which can recognize an object on and around a road in images acquired by an on-vehicle camera.
According to a first aspect of the present invention, there is provided a camera attitude parameter generating apparatus comprising:
an on-vehicle camera mounted on a vehicle to acquire an image ahead of or behind the vehicle;
means for detecting a pair of road parallel lines in the image acquired by the on-vehicle camera while the vehicle is traveling on a road, each of the road parallel lines being parallel with the longitudinal direction of the road;
means for obtaining the intersection of the pair of road parallel lines, thereby generating the intersection as a road vanishing point; and
parameter generating means for generating at least one of camera attitude parameters on the basis of the pair of road parallel lines and the road vanishing point, the camera attitude parameters representing the attitude of the on-vehicle camera with respect to the road.
Here, the camera attitude parameters may include the yaw angle, roll angle, pitch angle of the on-vehicle camera with respect to a road, and a traverse deviation distance of the vehicle from a predetermined first reference line associated with the road.
The camera attitude parameter generating apparatus may further comprise a position detection device including sensors and road map data, the position detection device detecting first support information including a bearing, a position, and a mileage of the vehicle, wherein the parameter generating means uses the first support information in generating the camera attitude parameters.
The position detection device may provide the parameter generating means with the bearing of the vehicle and a bearing of the road from the position detection device, and the parameter generating means may obtain an angle between the bearing of the vehicle and the road parallel lines on the basis of the difference between the bearing of the vehicle and the bearing of the road, and may use the angle for calculating the camera attitude parameters.
The parameter generating means may consider the angle between the bearing of the vehicle and the road parallel lines to be zero if the difference between the change in the bearing of the vehicle and the change in the bearing of the road while the vehicle travels a predetermined distance is less than a predetermined value.
The parameter generating means may consider the angle between the bearing of the vehicle and the road parallel lines to be zero if the change in the bearing of the vehicle continues to be less than a predetermined value for a predetermined distance.
The parameter generating means may generate the attitude parameters only when the angle between the bearing of the vehicle and the road parallel lines is zero.
The parameter generating means may obtain the bearing of the vehicle from the position detection device, and may inhibit the generation of the camera attitude parameters if the change in the bearing of the vehicle is greater than a predetermined value.
The position detection device may provide the parameter generating means with information associated with the speed of the vehicle, and the parameter generating means may generate the camera attitude parameters when the speed of the vehicle is within a predetermined range.
The position detection device may provide the parameter generating means with information associated with the acceleration of the vehicle, and the parameter generating means may inhibit the generation of the camera attitude parameters when the acceleration
Shimoura Hiroshi
Tenmoku Kenji
Britton Howard
Diep Nhon T
IP Group of Pillsbury Madison & Sutro LLP
Sumitomo Electric Industries Ltd.
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