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Correction Method for a Line Positioning Error in an Optical Character Reader

IP.com Disclosure Number: IPCOM000075962D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Linnerooth, JD: AUTHOR [+3]

Abstract

Sometimes the document transport of an optical character reader (OCR) machine will not stop the document so that the line 10 of characters to be read is entirely under the path 11 of the scanner, Fig. 1. An optimum correction of document position can be made in one try, by observing the relative position 12 of the characters to the scan area during prescan. This information is used to increment the stepping motor in either direction to provide proper positioning of the document, as shown in Fig. 2.

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Correction Method for a Line Positioning Error in an Optical Character Reader

Sometimes the document transport of an optical character reader (OCR) machine will not stop the document so that the line 10 of characters to be read is entirely under the path 11 of the scanner, Fig. 1. An optimum correction of document position can be made in one try, by observing the relative position 12 of the characters to the scan area during prescan. This information is used to increment the stepping motor in either direction to provide proper positioning of the document, as shown in Fig. 2.

Description of Flow Chart (Fig. 3)

Step 21. Checks prescan data for line centering criteria.

Step 22. Conditions stepping motor to move transport forward, if a line centering correction is necessary.

Step 23. Determines whether a "Character Out Top" (COT) condition, such as at 13, Fig. 1, is present.

Step 24. Stepping motor is conditioned to move transport backward, if COT condition is indicated.

Step 25. Index Register (IR) is set to one's complement of number of correction steps necessary.

Step 26. Adds one to IR.

Step 27. Compares IR contents against a predetermined constant, such as 256.

Step 28. If IR does not equal 256, stepping motor is pulsed to step one increment.

Step 29. Check is made to confirm that step has been taken before again adding a one to the IR.

Step 30. When IR equals 256, a second prescan is taken after line centering correction is made.

Step 31. A check is made to det...