Browse Prior Art Database

Four Byte Sequence Reversal

IP.com Disclosure Number: IPCOM000076168D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Balm, GJ: AUTHOR [+7]

Abstract

In an optical character reader (OCR) the reading of characters takes place by vertically scanning in columnar increments.

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Four Byte Sequence Reversal

In an optical character reader (OCR) the reading of characters takes place by vertically scanning in columnar increments.

Some OCR scanners can scan characters from bottom to top only. On a read forward, the procedure is scan bottom to top, step left to right, reset, scan bottom to top, etc. (Fig. 1A). On a read backward, the procedure is scan bottom to top, step left, reset, scan bottom to top, etc. (Fig. 1B).

During the read backward, on a 4-byte basis, the order of scan for proper CPU transfer is correct, i.e., the 20th (last) position is scanned last (Fig. 1B).

During a read forward, on a 4-byte basis, the bottom to top scan collects data in the reverse order from which the bytes should be serially transferred to CPU. The 4th byte position of data is scanned 1st and the 1st byte of data is scanned 4th (Fig. 1A).

For this reason, during the read forward, the byte transfer is reversed on a 4- byte basis before transfer to CPU.

The byte order as received by CPU storage is shown in Figs. 1C (read forward) and 1D (read backward). Effectively a reversal of the entire video pattern has been accomplished in read forward.

The video pattern from a particular character scanned, both forward and backward, would be the same except for address location. This is necessary if a single recognition means is used to recognize characters scanned in both directions. In order to utilize a single recognition means, the read-backward byte pattern of Fig....