Maze pattern analysis with image matching
First Claim
1. A computer-readable medium for analyzing a captured image of a document, wherein the document contains an embedded interaction code (EIC) pattern, and having computer-executable instructions to perform the steps comprising:
- (A) determining an affine transform and affine grid lines associated with the affine transform;
(B) extracting an initial bit matrix (B0) from a pre-processed image using the affine grid lines;
(C) generating a first generated pattern image (I1) from the initial bit matrix;
(D) obtaining a first perspective transform (T1) by matching the pre-processed image and the first generated pattern image and obtaining first perspective grid lines associated with the first perspective transform; and
(E) extracting a first bit matrix (B1) from the pre-processed image using the first perspective grid lines.
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Accused Products
Abstract
Processes and apparatuses analyze an image of a maze pattern in order to extract bits encoded in the maze pattern by iteratively obtaining a perspective transform from the captured image plane to the paper plane. The embedded interactive data is recognized by obtaining a perspective transform between the captured image plane and paper plane based on an obtained affine transform. The perspective transform typically models the relationship between two planes more precisely than the affine transform. The number of error bits in the extracted bit matrix is typically reduced, thus enabling decoding of position information to be more efficient and robust.
118 Citations
20 Claims
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1. A computer-readable medium for analyzing a captured image of a document, wherein the document contains an embedded interaction code (EIC) pattern, and having computer-executable instructions to perform the steps comprising:
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(A) determining an affine transform and affine grid lines associated with the affine transform;
(B) extracting an initial bit matrix (B0) from a pre-processed image using the affine grid lines;
(C) generating a first generated pattern image (I1) from the initial bit matrix;
(D) obtaining a first perspective transform (T1) by matching the pre-processed image and the first generated pattern image and obtaining first perspective grid lines associated with the first perspective transform; and
(E) extracting a first bit matrix (B1) from the pre-processed image using the first perspective grid lines. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for analyzing a captured image of a document that contains an embedded interaction code (EIC) pattern, comprising:
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an affine transform analyzer that determines an affine transform corresponding to a pre-processed image and that determines an initial bit matrix from affine grid lines that are associated with the affine transform; and
a perspective transform analyzer that iteratively determines an ith bit matrix (Bi) by utilizing an ith perspective transform (Ti) and the pre-processed image. - View Dependent Claims (16, 17, 18, 19)
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20. A method for analyzing a captured image of a document, the document containing an embedded interaction code (EIC) pattern, the method comprising:
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(A) normalizing the captured image for non-uniform illumination to obtain a pre-processed image;
(B) determining an affine transform and affine grid lines associated with the affine transform;
(C) extracting an initial bit matrix (B0) from the pre-processed image using the affine grid lines;
(D) obtaining an ith perspective transform (Ti) by matching the pre-processed image and the ith generated pattern image (Ii) and obtaining ith perspective grid lines associated with the ith perspective transform;
(E) determining an ith bit matrix (Bi) from the pre-processed image using the ith perspective grid lines;
(F) comparing the ith bit matrix with an (i−
1)th bit matrix (Bi−
1);
(G) if the ith bit matrix equals the (i−
1)th bit matrix, setting final extracted bits to the ith bit matrix; and
(H) if the ith bit matrix does not equal the (i−
1)th bit matrix, repeating (D)-(G).
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Specification