Method and system for universal lane boundary detection
First Claim
Patent Images
1. A method of detecting road or lane identifiers, comprising the steps of:
- receiving an image of a road in front of a vehicle from a video imager;
determining a region of interest in an identified road in the image using an image processing device; and
detecting road markings by detecting lane markings in the region of interest, and if lane markings cannot be detected, then detecting road boundaries in the region of interest;
wherein detecting road markings includes;
determining luminance gradients in the region of interest; and
detecting road markings by comparing the luminance gradients to a strength threshold;
and wherein determining luminance gradients includes determining edge strength in the region of interest to identify potential road marking edges;
and wherein detecting road markings includes comparing edge strength to said strength threshold by determining peaks and valleys in luminance gradients of image pixels, wherein a gradient peak represents an edge in the image, and a gradient valley represents an edge in the image;
and wherein detecting road markings further includes for multiple image rows in the region of interest;
identifying a pair of edges as potential road marking edges by comparing each edge strength to said edge strength threshold;
determining spacing between the pair of edges; and
comparing said spacing to spacing minimum and maximum thresholds;
wherein if the edge pair spacing is between the minimum and maximum thresholds, then the edge pair represents a potential lane marking;
passing a curve fit through the identified candidate points corresponding to edge pairs in said row representing potential lane markings; and
selecting all edge pairs that contributed to an acceptable first approximate line fit, as lane marking identifiers.
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Abstract
A method and system for detecting road markings, is provided. One implementation involves receiving an image (3) of a road (4) in front of a vehicle (2) from an imager (1), determining a region of interest in an identified road in the image, and detecting road markings (8L, 8R) by detecting lane markings (7L, 7R) in the region of interest, and if lane markings cannot be detected, then detecting road boundaries in the region of interest.
50 Citations
17 Claims
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1. A method of detecting road or lane identifiers, comprising the steps of:
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receiving an image of a road in front of a vehicle from a video imager; determining a region of interest in an identified road in the image using an image processing device; and detecting road markings by detecting lane markings in the region of interest, and if lane markings cannot be detected, then detecting road boundaries in the region of interest; wherein detecting road markings includes; determining luminance gradients in the region of interest; and detecting road markings by comparing the luminance gradients to a strength threshold; and wherein determining luminance gradients includes determining edge strength in the region of interest to identify potential road marking edges; and wherein detecting road markings includes comparing edge strength to said strength threshold by determining peaks and valleys in luminance gradients of image pixels, wherein a gradient peak represents an edge in the image, and a gradient valley represents an edge in the image; and wherein detecting road markings further includes for multiple image rows in the region of interest; identifying a pair of edges as potential road marking edges by comparing each edge strength to said edge strength threshold; determining spacing between the pair of edges; and comparing said spacing to spacing minimum and maximum thresholds; wherein if the edge pair spacing is between the minimum and maximum thresholds, then the edge pair represents a potential lane marking; passing a curve fit through the identified candidate points corresponding to edge pairs in said row representing potential lane markings; and selecting all edge pairs that contributed to an acceptable first approximate line fit, as lane marking identifiers. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for detecting road markings, comprising:
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an image processor configured to receive an image of a road in front of a vehicle from an imager, determine a region of interest in an identified road in the image; a road marking detection module configured to detect lane markings in the region of interest, and if lane markings cannot be detected, then detect road boundaries in the region of interest; wherein the image processor is further configured to determine luminance gradients in the region of interest; and wherein the road marking detection module is further configured to detect road markings by comparing the luminance gradients to a strength threshold; and wherein the image processor is further configured to determine luminance gradients by determining edge strength in the region of interest to identify potential road marking edges; and wherein the road marking detection module is further configured to compare edge strength to said strength threshold by determining peaks and valleys in luminance gradients of image pixels, wherein a gradient peak represents an edge in the image, and a gradient valley represents an edge in the image; wherein the road marking detection module is further configured such that in multiple image rows in the region of interest, the road marking detection module performs; identifying a pair of edges as potential road marking edges by comparing each edge strength to said strength threshold; determining spacing between the pair of edges; and comparing said spacing to spacing minimum and maximum thresholds; wherein if the edge pair spacing is between the minimum and maximum thresholds, then the edge pair represents potential lane marking; passing a curve fit through the identified candidate points corresponding to edge pairs in said row representing potential lane markings; and the road marking detection module selects all edge pairs that contributed to an acceptable first approximate line fit, as lane marking identifiers. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A system for detecting road surface reflections, comprising:
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an imager configured to generate an image of a road in front of a vehicle; an image processor configured to determine a region of interest in an identified road in the image; a road marking detection module configured to detect lane markings in the region of interest, and if lane markings cannot be detected, then detect road boundaries in the region of interest; and a road departure detection module configured to detect proximity of the vehicle relative to the detected road markings; wherein the image processor is further configured to determine luminance gradients by determining edge strength in the region of interest to identify potential road marking edges; wherein the road marking detection module is further configured to compare edge strength to said strength threshold by determining peaks and valleys in luminance gradients of image pixels, wherein a gradient peak represents an edge in the image, and a gradient valley represents an edge in the image; and wherein the road marking detection module comprises a lane marking detection module configured such that in multiple image rows in the region of interest, the lane marking detection module performs; identifying a pair of edges as potential road marking edges by comparing each edge strength to said strength threshold; determining spacing between the pair of edges; and comparing said spacing to spacing minimum and maximum thresholds; wherein if the edge pair spacing is between the minimum and maximum thresholds, then the edge pair represents potential lane marking; passing a curve fit through the identified candidate points corresponding to edge pairs in said row representing potential lane markings; and the road marking detection module selects all edge pairs that contributed to an acceptable first approximate line fit, as lane marking identifiers. - View Dependent Claims (14, 15, 16, 17)
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Specification