Browse Prior Art Database

Filterable Preprinted Guidelines for Optical Character Recognition

IP.com Disclosure Number: IPCOM000078805D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Hamburgen, A: AUTHOR

Abstract

Many types of documents for use in optical character recognition (OCR) and similar systems contain preprinted guides for indicated areas, in which hand-printed or machine-printed characters are to be placed. Such guides must not produce signals in the system output. This effect is usually produced by printing the guides with a "drop-out" ink, which is not detectable by the scanner. But, since OCR scanners made by different manufacturers have widely differing spectral characteristics, an ink which drops out for one scanner may be detected by another scanner.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 69% of the total text.

Page 1 of 2

Filterable Preprinted Guidelines for Optical Character Recognition

Many types of documents for use in optical character recognition (OCR) and similar systems contain preprinted guides for indicated areas, in which hand- printed or machine-printed characters are to be placed. Such guides must not produce signals in the system output. This effect is usually produced by printing the guides with a "drop-out" ink, which is not detectable by the scanner. But, since OCR scanners made by different manufacturers have widely differing spectral characteristics, an ink which drops out for one scanner may be detected by another scanner.

In the present system, guides are preprinted in such a way that they may be filtered out without any prior knowledge of their size, shape or location. Fig. 1 shows a document 10 having a line of preprinted guide boxes 11 for hand-print characters. Optical scanner 12 detects the characters printed in boxes 11, and may detect the boxes as well. Electronic filter circuits 13, found in many conventional OCR systems, filter out small "noise" marks on document AO. The lower frequency signals produced by valid character strokes are passed to recognition unit 14 for identification.

Fig. 2 shows a larger partial view of the line of guide boxes 11 as they appear to the eye. Boxes 11 are not continuous, but are actually composed of small, closely spaced shapes, such as the dots 15 shown in Fig. 3A. Dots 15 may be, for example, about 0.005 inch in diamete...