Image Skew Detection Apparatus And Methods
First Claim
1. A method for skew detection in an image, the method comprising:
- detecting a first line in the image;
determining whether the first line is reliable; and
calculating a skew angle of the image based on an orientation of the first line with respect to an orientation of the image if the first line is reliable.
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Accused Products
Abstract
Methods and apparatus for detecting skew in a document image, such as a check image, to produce a de-skewed image are described. One example method includes detecting one or more lines in the image and determining whether the one or more lines are reliable. Reliability of a line may be based on at least one of line length, straightness, and the presence of holes in the line. If one or more lines are reliable, the method may calculate a skew angle of the image based on the one or more reliable lines'"'"' orientations with respect to an orientation of the image. A comparison may also be made between lines detected in different regions of the check to determine if a difference between skew angles corresponding to each of the compared lines is lower than an error threshold.
213 Citations
22 Claims
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1. A method for skew detection in an image, the method comprising:
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detecting a first line in the image; determining whether the first line is reliable; and calculating a skew angle of the image based on an orientation of the first line with respect to an orientation of the image if the first line is reliable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for detecting skew in an image to produce a de-skewed image, the method comprising:
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scanning a first region of the image for a first group of one or more lines; scanning a second region of the image for a second group of one or more lines if none of the lines in the first group of one or more lines is reliable; and if none of the lines in the second group of one or more lines is reliable; comparing an angle of a line in the first group of one or more lines with an angle of a line in the second group of one or more lines; and determining the skew angle of the image based on the comparison of the first and second line angles if a difference between skew angles corresponding to each of the compared first and second line angles is lower than an error threshold. - View Dependent Claims (16, 17, 18, 19)
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20. One or more computer-readable media having computer-executable instructions thereon which, when executed, implement a method for skew detection in an image, the method comprising:
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scanning a first region of the image for a first group of one or more lines; scanning a second region of the image for a second group of one or more lines if none of the lines in the first group of one or more lines is reliable; and if none of the lines in the second group of one or more lines is reliable; comparing an angle of a line in the first group of one or more lines with an angle of a line in the second group of one or more lines; and determining the skew angle of the image based on the comparison of the first and second line angles if a difference between skew angles corresponding to each of the compared first and second line angles is lower than an error threshold. - View Dependent Claims (21, 22)
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Specification