Document registration and skew detection system
First Claim
Patent Images
1. A digital imaging system, comprising:
- a digital image capture device configured to generate a scan image that digitally represents an input document positioned in a scan area;
an image processor configured to receive and process said scan image in real-time, wherein said image processor includes an input document edge detection system, an input document corner detection system, an input document skew calculation system and an input document shear calculation system; and
an output processor configured to provide registration information for said input document.
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Abstract
Disclosed methods and systems perform electronic registration of digitally captured images in real-time and performs accurate and robust digital image processing by analyzing the entire digitally captured image.
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Citations
20 Claims
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1. A digital imaging system, comprising:
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a digital image capture device configured to generate a scan image that digitally represents an input document positioned in a scan area;
an image processor configured to receive and process said scan image in real-time, wherein said image processor includes an input document edge detection system, an input document corner detection system, an input document skew calculation system and an input document shear calculation system; and
an output processor configured to provide registration information for said input document. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method, comprising:
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generating a digital representation of a scan image that represents an input document positioned in a scan area;
identifying pixels of said scan image that correspond to a first captured portion of said input document;
detecting scan image scanlines that correspond to a plurality of input document edges; and
generating registration information for said input document reproduction based upon at least one of said input document skew angle and said input document shear amount. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method, comprising:
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receiving a scan image that digitally represents an input document positioned in a scan area; and
detecting a fast-scan direction aligned input document edge by (i) obtaining a first grayscale average for a scan image target pixel and a pixel aligned with said target pixel in a slow-scan direction in a first previously processed scanline, (ii) obtaining a second grayscale average for pixels that are aligned with said target pixel in a slow-scan direction in at least a second and third previously processed scanline, (iii) obtaining a difference between said first grayscale average and said second grayscale average;
(iv) obtaining a grayscale difference threshold that distinguishes background pixels and input document pixels and (v) designating said target pixel as a slow-scan transition pixel if said first and second grayscale average difference exceeds said grayscale difference threshold. - View Dependent Claims (18, 19, 20)
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Specification