Curvature correction and image processing
First Claim
1. A process for reading information on an unread form, the process comprising the steps of:
- storing a model image of a model of the unread form in a computer system, the model image containing alignment marks;
storing an unread image of the unread form in the computer system, the unread image containing alignment marks that correspond to the alignment marks on the model image;
partitioning the model image into a group of sectors, wherein each sector is defined by the locations of at least three alignment marks;
detecting the sectors on the unread image that correspond to the sectors on the model image by comparing the alignment marks on the model image to the corresponding alignment marks on the unread image;
generating a transfer function for each sector of the unread image from the locations of corresponding alignment marks of the model image and the unread image;
applying each sector'"'"'s transfer function to the locations of marks on the corresponding sector of the unread image to generate a corrected unread image with corrected locations of the marks; and
reading information on the corrected unread image of the unread form.
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Accused Products
Abstract
A system and process for reading forms using a curvature distortion correction scheme is disclosed. A model image of a known form is partitioned into sectors defined by at least three alignment marks, and a transfer or correction function for each sector is generated by comparing the locations of alignment marks on a captured unread image of a form to those on a model image. The transfer function is then applied to the other marks within the sector to calculate a correct location of the marks. Each sector is sized to reasonably ensure curvature distortions are handled such that all the marks on a form are properly found and interpreted. Errors may be checked and, if they persist, smaller sectors may be defined and employed, if available.
102 Citations
20 Claims
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1. A process for reading information on an unread form, the process comprising the steps of:
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storing a model image of a model of the unread form in a computer system, the model image containing alignment marks; storing an unread image of the unread form in the computer system, the unread image containing alignment marks that correspond to the alignment marks on the model image; partitioning the model image into a group of sectors, wherein each sector is defined by the locations of at least three alignment marks; detecting the sectors on the unread image that correspond to the sectors on the model image by comparing the alignment marks on the model image to the corresponding alignment marks on the unread image; generating a transfer function for each sector of the unread image from the locations of corresponding alignment marks of the model image and the unread image; applying each sector'"'"'s transfer function to the locations of marks on the corresponding sector of the unread image to generate a corrected unread image with corrected locations of the marks; and reading information on the corrected unread image of the unread form. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for processing and correcting markings on a known form, the system comprising:
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a light source that illuminates a form that reflects some of the light; a camera arranged to receive the reflected light from the form and capture an unread image of the form; camera electronics to extract the unread image of the form from the camera, the unread image having alignment marks at locations; a computer processing system in communication with the camera electronics, the computer processing system comprising; at least one memory configured to store; the unread image of the form; a model image of the form having alignment marks; sectors defined by the locations of the alignment marks; and a transfer functions for each sector from the locations of corresponding alignment marks of the stored unread and model images; and at least one processor configured to execute an application that generates corrected locations of the alignment marks within each sector of the stored unread image by application of the transfer function to the alignment marks within each sector of the stored unread image. - View Dependent Claims (11, 12, 13)
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14. A computer readable medium encoded with computer executable program instructions for determining the location of marks on a known type of form, the computer executable program instructions comprising one or more program instructions for performing the steps of:
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storing a model image of a model of the unread form in a computer system, the model image containing alignment marks; storing an unread image of the unread form in the computer system, the unread image containing alignment marks that correspond to the alignment marks on the model image; partitioning the model image into a group of sectors, wherein each sector is defined by the locations of at least three alignment marks; detecting the sectors on the unread image that correspond to the sectors on the model image by comparing the alignment marks on the model image to the corresponding alignment marks on the unread image; generating a transfer function for each sector of the unread image from the locations of corresponding alignment marks of the model image and the unread image; and applying each sector'"'"'s transfer function to the locations of marks on the corresponding sector of the unread image to generate corrected locations of the marks, thereby enabling the reading of the unread form. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification