Marker and method for detecting said marker
First Claim
1. A marker detectable by visual means comprising:
- a. a polygonal border comprising of at least four non collinear salient points;
b. a binary digital code on said marker;
c. the binary digital code comprising information data, checksum and error correction;
d. a first level of binary digital code readable at a first given distance;
e. a second level of binary digital code readable at a second given distance;
f. where said second given distance is less than said first given distance; and
g. where said second level binary digital code is smaller in size than the first level binary digital code and does not interfere with the reading of said first level binary digital code.
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Accused Products
Abstract
This invention discloses marker detectable by visual means comprising; a polygonal border having of at least four non collinear salient points. The marker has on it a pattern in binary digital code. The binary code data contains information data, checksum and error correction. The binary code data is on two levels; a first level of binary code readable at a first given distance, a second level of binary code readable at a second given distance, where the second given distance is less than the first given distance and the second level binary code is smaller in size than the first level binary code. The second level of binary code does not interfere with the reading of the first level binary code. It also discloses a method for detecting a marker comprising the steps of detecting an image, using an edge detector to detect an edge in said image, grouping more than one edge into a polygon having salient points, calculating homography from polygon salient points, generating a list of homographies, extracting binary data from input image having homographies, identifying and verifying binary data.
46 Citations
18 Claims
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1. A marker detectable by visual means comprising:
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a. a polygonal border comprising of at least four non collinear salient points; b. a binary digital code on said marker; c. the binary digital code comprising information data, checksum and error correction; d. a first level of binary digital code readable at a first given distance; e. a second level of binary digital code readable at a second given distance; f. where said second given distance is less than said first given distance; and g. where said second level binary digital code is smaller in size than the first level binary digital code and does not interfere with the reading of said first level binary digital code. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for detecting a marker comprising the steps:
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a. detecting an image to be evaluated using an image sensor; b. using an edge detector to detect an edge in said image; c. grouping more than one edge into a polygon having salient points; d. calculating homography from polygon salient points; e. generating a list of homographies; f. extracting binary data from input image having homographies; q. verifying if the image is a marker by performing check sum and error correction functions; h. if the image is a marker, identify as a marker and verify binary data. - View Dependent Claims (13, 14)
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15. A method for identifying a marker comprising:
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a. detecting a potential marker to be evaluated using an image sensor; b. detecting edgels using an edge detector; c. grouping edgels into line segments; d. making a list of line segments; e. grouping line segments into polygons; f. making a list of polygons. - View Dependent Claims (16, 17, 18)
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Specification