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Measurements With Closed Circuit Television

IP.com Disclosure Number: IPCOM000090627D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Bojman, W: AUTHOR

Abstract

The system uses closed-circuit television that allows the measurement or dimensioning of an object displayed upon the television screen. A single-shot circuit generates a pulse of a duration approximating that of the horizontal flyback time of the TV monitor, for example, 1 micro second in the case of a standard TV system. The single-shot is triggered by the horizontal sync pulse received from the TV camera control or picked up within the TV monitor. The sawtooth generator produces a linear voltage ramp the duration of which equals that of the horizontal sweep. A circuit for this purpose consists of a constant-current source charging a capacitor while a switch, turned on by the single-shot pulse, discharges it during the flyback.

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Measurements With Closed Circuit Television

The system uses closed-circuit television that allows the measurement or dimensioning of an object displayed upon the television screen. A single-shot circuit generates a pulse of a duration approximating that of the horizontal flyback time of the TV monitor, for example, 1 micro second in the case of a standard TV system. The single-shot is triggered by the horizontal sync pulse received from the TV camera control or picked up within the TV monitor. The sawtooth generator produces a linear voltage ramp the duration of which equals that of the horizontal sweep. A circuit for this purpose consists of a constant-current source charging a capacitor while a switch, turned on by the single-shot pulse, discharges it during the flyback. The comparator is a regenerative difference amplifier capable of fast transition from one to another output level whenever the difference between the two input signals reverses polarity. The differentiation, shaping, and amplifying that follow the comparator serve to obtain a pulse suitable to superimpose on the video signal in order to produce an intensified or darkened spot, at the user's discretion, on each scan line of the TV tube screen.

Since the process is repetitious and the time delay between sync and output pulses is a constant until the DC input to the comparator is altered, a bright or dark vertical line appears on the TV screen, superimposed on the normal picture. The DC voltage ap...