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Line Stroke Width Normalization

IP.com Disclosure Number: IPCOM000091338D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 40K

Publishing Venue

IBM

Related People

Norman, RJ: AUTHOR

Abstract

In a character recognition system having scanner 10 and recognition circuits 12, the scan path is a straight line which crosses line strokes forming the character to be read. The position of these line strokes can be detected and used by the recognition circuits to identify the character being scanned. The position of interest is the center of the line stroke that is intersected by the beam from scanner 10.

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Line Stroke Width Normalization

In a character recognition system having scanner 10 and recognition circuits 12, the scan path is a straight line which crosses line strokes forming the character to be read. The position of these line strokes can be detected and used by the recognition circuits to identify the character being scanned. The position of interest is the center of the line stroke that is intersected by the beam from scanner 10.

The remaining apparatus in drawing 1 accurately defines the center of a line stroke of a character as the scanning beam crosses the stroke of the character. The digitized video signal from voltage discriminator 11, in addition to going to recognition circuits 12, is also passed to differentiating circuit 14. During a white- to-black transition as the video beam starts into a stroke of a character, the digitized video signal is rising so the output from circuit 14 is a positive pulse. This positive pulse turns on current source 16. Current Is from source 16 causes the voltage on capacitor 18 to rise at a linear rate controlled by the value of the current from source 16. When the digitized video drops indicating a black-to- white transition as the scanning beam moves off the stroke of the character, circuit 14 has a negative pulse output. The latter has no effect on the current source 16. However, the negative pulse is inverted by Inverter 20 to a positive pulse which turns on current source 22. This source also has an output current of Is which acts to increase the voltage on capacitor 18. The currents from sources 16 and 22 are identical so, when both sources are on, the rate of voltage rise on capacitor 18 is double the rate when only current source 16 is on.

When the voltage on capacitor 18 reaches a voltage level Vo, voltage discriminator 24 has an output. This output is only a momentary pulse as feedback through single-shot 26 from discriminator 24 acts to turn on transistor 28 which then discharges capacitor 18 turning off discriminator 24. The pulse out of discriminator 24 is used to define a time to circuits 12 in which this time is a fixed time interval...