System and method for estimating lateral position
First Claim
1. A system for estimating lateral offset of a vehicle from a known position, comprising:
- input means producing digitized input signals representative of the road ahead of the vehicle;
means for sampling said digitized input signals to create a perspective-free image, said perspective-free image taking the form of a matrix comprised of rows and columns;
means for determining the curvature of the road by determining an amount each row of said perspective-free image must be shifted to cause features to appear in said perspective-free image as straight lines, said means for determining including means for adding each column of said shifted perspective-free image to generate a current scanline profile representative of the vehicle'"'"'s position on the road;
means for storing at least one template profile representative of a known vehicle position; and
means for comparing said current scanline profile with said template profile to determine an amount by which said current scanline profile must be shifted to arrive at the best correlation with said template profile, said amount being representative of the lateral offset of the vehicle from the known vehicle position.
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Abstract
A system for estimating lateral offset of a vehicle from a centered position on a road is comprised of a video camera and a digitizer to produce digitized input signals representative of the road ahead of the vehicle. A circuit is provided for sampling the digitized input signal to create a perspective-free image comprised of rows and columns of pixels. The curvature of the road is determined by ascertaining an amount by which each row of pixels of the perspective-free image must be horizontally shifted to cause features to appear in the perspective-free image as a straight line. Each column of pixels of the perspective-free image is added to produce a single row, referred to as a current scanline profile, representative of the vehicle'"'"'s position on the road. The current scanline profile is compared with a template profile representative of the vehicle'"'"'s position when properly centered on a straight road to determine an amount by which the current scanline profile must be shifted to arrive at an optimal correlation with the template profile. The amount that the current scanline profile must be shifted is representative of the lateral offset of the vehicle from the center of the road. Circuitry is responsive to the lateral offset and the curvature of the road to produce an appropriate output signal.
242 Citations
31 Claims
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1. A system for estimating lateral offset of a vehicle from a known position, comprising:
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input means producing digitized input signals representative of the road ahead of the vehicle; means for sampling said digitized input signals to create a perspective-free image, said perspective-free image taking the form of a matrix comprised of rows and columns; means for determining the curvature of the road by determining an amount each row of said perspective-free image must be shifted to cause features to appear in said perspective-free image as straight lines, said means for determining including means for adding each column of said shifted perspective-free image to generate a current scanline profile representative of the vehicle'"'"'s position on the road; means for storing at least one template profile representative of a known vehicle position; and means for comparing said current scanline profile with said template profile to determine an amount by which said current scanline profile must be shifted to arrive at the best correlation with said template profile, said amount being representative of the lateral offset of the vehicle from the known vehicle position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A system for estimating lateral offset of a vehicle from a known position, comprising:
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input means producing digitized input signals representative of the road ahead of the vehicle; means for sampling said digitized input signals to create a perspective-free image, said perspective-free image taking the form of a matrix comprised of rows and columns; means for determining the curvature of the road by determining an amount each row of said perspective-free image must be shifted to cause features to appear in said perspective-free image as straight lines, said means for determining including means for adding each column of said perspective-free image to generate a current scanline profile representative of the vehicle'"'"'s position on the road; means for storing a plurality of template profiles representative of known vehicle positions; means for selecting one of said stored template profiles; and means for comparing said current scanline profile with said selected template profile to determine an amount by which said current scanline profile must be shifted to arrive at the best correlation with said selected template profile, said amount being representative of the lateral offset of the vehicle and the known vehicle position.
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31. A method for estimating lateral offset of a vehicle from a known position, said method comprising the steps of:
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producing digitized input signals representative of the road ahead of the vehicle; sampling said digitized input signals to create a perspective-free image, said perspective-free image taking the form of a matrix comprised of rows and columns; determining the curvature of the road by determining an amount each row of said perspective-free image must be shifted to cause features to appear in said perspective-free image as straight lines, said step of determining including the step of adding each column of said shifted perspective-free image to generate a current scanline profile representative of the vehicle'"'"'s position on the road; storing a template profile representative of a known vehicle position; and comparing said current scanline profile with said template profile to determine an amount by which said current scanline profile must be shifted to arrive at the best correlation with said template profile, said amount being representative of the lateral offset of the vehicle from the known vehicle position.
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Specification