Patent EP0411231A2 successfully refreshed from Google Patents.
EP0411231A2
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EP
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Method for digitizing information written into forms by means of very large symbol matching
Assignee: International Business Machines Corp
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Filing: 1989-10-10
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Granted: —
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Expires: 2009-10-10
Abstract
Abstract This method relates to the compression of information contained in filled-in forms (0) by separate handling of the corresponding empty forms (CP) and of the information written into them (VP). Samples of the empty forms are pre-scanned, the data obtained digitized and stored in a computer memory to create a forms library. The original, filled-in form (0) to be compressed is then scanned, the data obtained digitized and the retrieved representation of the empty form (CP) is then subtracted, the difference being the digital representation of the filled-in information (VP), which may now be compressed by conventional methods or, preferably, by an adaptive compression scheme using at least two compression ratios depending on the relative content of black pixels in the data to be compressed.
Inventors
- 👤 Dan Shmuel Dr. Chevion
- 👤 Ehud Dov Dr. Karnin
- 👤 Eugeniusz Dr. Walach
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 13:36
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/41; H04N1/411; H04N1/4115
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
147 words
Method for compressing, for storage or transmission, the information contained in filled-in forms (O) by separate handling of the corresponding empty forms (CP) and of the information written into them (VP), characterized by the steps of: - pre-scanning the empty forms (CP), digitizing the data obtained, and storing the digitized representations relating to each of the empty forms (CP) in a computer memory to create a forms library, - scanning the original, filled-in form (0) to be compressed, digitizing the data obtained, - identifying the particular one of said empty forms (CP) in said forms library and retrieving the digital representation thereof, - subtracting said retrieved representation of the empty form (CP) from said digital representation of the scanned filled-in form (O), the difference being the digital representation of the filled-in information (VP), and - compressing the digital representation of the filled-in information (VP) by appropriate methods.
Claim 2
Dependent Claim
147 words
Method for compressing, for storage or transmission, the information contained in filled-in forms (O) by separate handling of the corresponding empty forms (CP) and of the information written into them (VP), characterized by the steps of: - pre-scanning the empty forms (CP), digitizing the data obtained, and storing the digitized representations relating to each of the empty forms (CP) in a computer memory to create a forms library, - scanning the original, filled-in form (0) to be compressed, digitizing the data obtained, - identifying the particular one of said empty forms (CP) in said forms library and retrieving the digital representation thereof, - subtracting said retrieved representation of the empty form (CP) from said digital representation of the scanned filled-in form (O), the difference being the digital representation of the filled-in information (VP), and - compressing the digital representation of the filled-in information (VP) by appropriate methods.
Claim 3
Dependent Claim
33 words
Method in accordance with claim 1, characterized in that the scanning parameters, such as brightness and threshold level, are determined separately for the empty form (CP) and for said original filled-in form (O).
Claim 4
Dependent Claim
50 words
Method in accordance with claim 1, characterized in that prior to the subtraction step, registration information relating to the relative position of the filled-in information (VP) with respect to the completed form (0) is determined and registration of said original filled-in form (O) with said empty form (CP) is performed.
Claim 5
Dependent Claim
18 words
Method in accordance with claim 3, characterized in that the said registration information is determined through dimensionality reduction.
Claim 6
Dependent Claim
88 words
Method in accordance with claim 3, characterized in that said registration is performed in the following sequence of steps: - partitioning the the scanned filled-in form (0) into small segments, - estimating, for each segment, the optimum shifts to be performed in x- and y directions, - placing each segment of said original filled-in form (0) at the appropriate area of the output image array using the shift information previously established, so that a complete, shifted image is obtained when the placements for all segments have been completed.
Claim 7
Dependent Claim
34 words
Method in accordance with claim 5, characterized in that said original filled-in form (O) is partitioned in a proportion corresponding at least approximately to 16 segments per page of 210 x 297 mm size.
Claim 8
Dependent Claim
29 words
Method in accordance with claim 5, characterized in that said partitioning is performed such that the segments overlap at their margins by a distance corresponding to about two pixels.
Claim 9
Dependent Claim
43 words
Method in accordance with claim 5, characterized in that said estimated optimum shifts for each pair of neighbouring segments are checked for consistency by assuring that their difference does not exceed a predetermined threshold and, if it does, automatically calling for operator intervention.
Claim 10
Dependent Claim
58 words
Method in accordance with claim 1, characterized in that said subtraction step involves removing, from the original filled-in form (0), all black pixels which belong to said corresponding empty form (CP) or which are located close to black pixels belonging to said corresponding empty form (CP), and retaining all black pixels which belong to said filled-in information (VP).
Claim 11
Dependent Claim
71 words
Method in accordance with claim 1, characterized in that said compression step involves the application of at least two different compression ratios depending on the content, in the data to be compressed, of portions containing a comparatively large number of black pixels and portions containing a comparatively small number of black pixels, with the data to be compressed being first subjected to a pre-filtering step to determined the relative compressibility thereof.
Claim 12
Dependent Claim
38 words
Method in accordance with any one of the preceding claims, characterized in that all steps are performed with the said binary representations being maintained in a byte format without unpacking any of the bytes to their component pixels.
References Cited (Backward Citations)
No citation records indexed.
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