METHOD AND SYSTEM FOR ONLINE CALIBRATION OF A VIDEO SYSTEM
First Claim
1. A method for online calibration of a vehicle video system using vanishing points evaluated from frames of a camera image taken by a vehicle camera comprising identified markings or edges on a road, comprising:
- locating the vanishing points by finding or extrapolating at least at one left-hand or one right-hand side markings of the road to a point of intersection;
calculating a long-term average vanishing point location using time-filtering methods from a sequence of camera images when only one side of the road markings is visible in one of the frames of the camera images at a time; and
deducing a static yaw and a pitch angle of the camera using coordinates of the long-term average vanishing point location.
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Abstract
The present invention relates to video-based driver assistance systems being used in vehicles today to perform a variety of functions, such as lane or road departure warning. These functions often require that parts of the video image be identified as, for example, a traffic sign, a bridge, lane markings, etc. Particularly the present invention relates to a method and system for online calibration of a vehicle video system using vanishing points, evaluated from frames of a camera image contains identified markings or edges on a road. The vanishing points are located by finding or extrapolating at least at one left- and/or right-hand side markings or edges of a mad to a point of intersection, whereby a long term average vanishing point location is calculated with time-filtering methods from a sequence of images, even when only one side of a road or lane marking or an edge is visible in any given frame of an image at a time, and from the time-averaged vanishing point location coordinates, the static yaw and pitch angles of the camera are deduced. The present invention relates to also to a method to locate the vanishing points by finding or extrapolating the regularity of repeated road markings, such as dashed patterns and to a method to locate the vanishing point d by using the change in spatial frequency of textures on the surface ahead as an object to determine the camera pitch angle.
62 Citations
12 Claims
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1. A method for online calibration of a vehicle video system using vanishing points evaluated from frames of a camera image taken by a vehicle camera comprising identified markings or edges on a road, comprising:
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locating the vanishing points by finding or extrapolating at least at one left-hand or one right-hand side markings of the road to a point of intersection; calculating a long-term average vanishing point location using time-filtering methods from a sequence of camera images when only one side of the road markings is visible in one of the frames of the camera images at a time; and deducing a static yaw and a pitch angle of the camera using coordinates of the long-term average vanishing point location. - View Dependent Claims (2, 3, 4, 5, 12)
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6. A method for online calibration of a vehicle video system with vanishing points evaluated from frames of a camera image comprising identified markings on a road, the method comprising:
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locating the vanishing points by finding or extrapolating a regularity of repeated road markings; determining a camera pitch angle using the regularity of repeated road markings; and calculating a long-term average vanishing point location using time-filtering methods from a sequence of camera images, wherein the vehicle comprises a driver assistant system and a lane-keeping system.
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7. A method for online calibration of a vehicle video system with vanishing points evaluated from frames of a camera image comprising identified scenes on a road, the method comprising:
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locating the vanishing points by using a change in spatial frequency of textures on a road surface ahead of a moving vehicle as an object; determining a camera pitch angle using the change in spatial frequency of textures on the road surface; and calculating a long-term average vanishing point location using time-filtering methods from a sequence of camera images, wherein the vehicle comprises a driver assistant system and a lane-keeping system.
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8. (canceled)
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9. A system for online calibration of a vehicle video system using vanishing points, evaluated from frames of a camera image comprising at least one of identified markings, scenes and edges on a road, comprising:
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an image processing apparatus comprising an electronic camera for a video-based detection of a road or scenes in front of the moving vehicle; and a computer based electronic circuit configured to; approximately locate the vanishing points, and deduce a camera pitch and yaw angles by extrapolation of the road markings and edges to sub-pixel precision, wherein deduction comprises accounting for camera distortion and an optical axis location, and wherein the computer based electronic circuit uses time filtering for successive refinement, wherein the vehicle comprises a driver assistant system with a lane-keeping system. - View Dependent Claims (10, 11)
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Specification