CAMERA AUTO-CALIBRATION BY HORIZON ESTIMATION
First Claim
1. A method for estimating a horizon on an image from a camera, said method comprising:
- providing first and second images from the camera;
providing a texture map from one of the images that locates edges in the image;
providing a motion map from a difference between the first and second images that locates areas in the images where no motion is occurring;
combining the texture map and the motion map to identify locations in the combined map that do not move and include horizontal edges;
providing a horizontal projection that includes a count of locations in the horizontal direction in the combined map that identify the number of horizontal edges in the combined map;
providing a smoothing of the horizontal projection to reduce noise in the horizontal projection; and
identifying a maximum peak in the smoothed horizontal projection that identifies the estimated horizon in the images.
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Accused Products
Abstract
A method for estimating the horizon in an image of a camera to provide camera auto-calibration in the pitch direction. The method includes taking an image of a scene and generating a texture map of the image using horizontal edge detection analysis to locate horizontal edges in the scene. The method also includes providing a motion map by providing image differencing between subsequent images to find areas in the scene with no motion while the vehicle is moving. The texture map and the motion map are combined to identify the areas in the image that do not move and contain horizontal edges. A horizontal projection is generated from the combined map by counting white dots in the map in the horizontal direction. The horizontal projection is smoothed to eliminate noise and the location of the horizon is estimated in the image by identifying the maximum peak in the horizontal projection.
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Citations
20 Claims
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1. A method for estimating a horizon on an image from a camera, said method comprising:
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providing first and second images from the camera; providing a texture map from one of the images that locates edges in the image; providing a motion map from a difference between the first and second images that locates areas in the images where no motion is occurring; combining the texture map and the motion map to identify locations in the combined map that do not move and include horizontal edges; providing a horizontal projection that includes a count of locations in the horizontal direction in the combined map that identify the number of horizontal edges in the combined map; providing a smoothing of the horizontal projection to reduce noise in the horizontal projection; and identifying a maximum peak in the smoothed horizontal projection that identifies the estimated horizon in the images. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for estimating a horizon in an image from a camera, said method comprising:
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providing first and second images from the camera; providing a texture map from one of the images that locates horizontal edges in the image as white dots where providing the texture map includes using a horizontal edge detection analysis to locate the horizontal edges; providing a motion map from a difference between the first and second images that locates areas in the images as white dots where no motion is occurring; combining the texture map and the motion map to identify locations in the combined map as white dots that do not move and include horizontal edges; providing a horizontal projection that includes a count in the horizontal direction of the white dots in the combined map that identifies the number of horizontal edges in the combined map; providing a smoothing of the horizontal projection to reduce noise in the horizontal projection; and identifying a maximum peak in the smoothed horizontal projection that identifies the estimated horizon in the images. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A system for estimating a horizon in an image from a camera, said method comprising:
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means for providing first and second images from the camera; means for providing a texture map from one of the images that locates edges in the image as white dots; means for providing a motion map from a difference between the first and second images that locates areas in the images as white dots where no motion is occurring; means for combining the texture map and the motion map to identify locations in the combined map as white dots that do not move and include horizontal edges; means for providing a horizontal projection that includes a count of the white dots in the horizontal direction in the combined map that identify the number of horizontal edges in the combined map; means for providing a smoothing of the horizontal projection to reduce noise in the horizontal projection; and means for identifying a maximum peak in the smoothed horizontal projection that identifies the estimated horizon in the images. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification