Cameras to determine vehicle heading
First Claim
1. A method of calculating a heading angle of a vehicle using a camera associated with said vehicle, said method comprising capturing at least two images with said camera, calculating a lateral speed of said vehicle from said two images, calculating a ground speed of said vehicle independently of said two images and calculating, from said ground speed and said lateral speed, a first heading angle of said vehicle and, further comprising a step of calculating a second heading angle from said images.
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Abstract
A method of calculating the heading angle of a vehicle using a camera associated with the vehicle, the method comprising capturing at least two images with the camera, calculating the lateral speed of the vehicle from the images, calculating the ground speed of the vehicle and calculating, from the ground speed and the lateral speed, a first heading angle of the vehicle. The method may also include calculating a second heading value from the images and from that a misalignment value indicative of the alignment of the camera from some datum. The misalignment value may be used to correct the first heading angle and the process repeated iteratively. The method may also include fitting features that follow features that follow the direction of travel of the vehicle. A camera system and data carrier embodying the method are also disclosed.
18 Citations
35 Claims
- 1. A method of calculating a heading angle of a vehicle using a camera associated with said vehicle, said method comprising capturing at least two images with said camera, calculating a lateral speed of said vehicle from said two images, calculating a ground speed of said vehicle independently of said two images and calculating, from said ground speed and said lateral speed, a first heading angle of said vehicle and, further comprising a step of calculating a second heading angle from said images.
- 13. A method of calculating a heading angle of a vehicle using a camera associated with said vehicle, said method comprising capturing at least two images with said camera, calculating a lateral speed of said vehicle from said two images, calculating a ground speed of said vehicle independently of said two images and calculating, from said ground speed and said lateral speed, a first heading angle of said vehicle and, further including the step of analyzing said two images in order to calculate heading angles by finding features that follow a direction of travel of said vehicle.
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23. A method of estimating an error in a measured heading angle of a vehicle travelling along a road, said road having features aligned along a length of said road, comprising the steps of:
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a) Periodically capturing images of said road with a camera; b) Analysing each image to determine a position of said features; c) Fitting said features to a curve; d) Calculating a lateral velocity of said curve relative to said vehicle; e) Dividing said lateral velocity by a ground speed of said vehicle to produce a ratio; f) Taking an inverse cosine of said ratio to produce an angle; g) Taking said angle away from 90°
to give a first heading angle;h) Calculating a second heading angle from a curve to which said features have been fitted; and i) Calculating a difference between said first heading angle and said second heading angle to give a misalignment value indicative of a misalignment between said camera and a datum. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification