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Optical Comparator for Visual Scanning of Drawings for Microfilming

IP.com Disclosure Number: IPCOM000094746D
Original Publication Date: 1965-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Huffman, HD: AUTHOR

Abstract

This optical comparator determines the line width and line density of drawings. Comparator readings can be used in conjunction with tables to inform a microfilm camera operator as to proper exposure of a film so that the lines of the drawings are reproducible through a lens system.

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Optical Comparator for Visual Scanning of Drawings for Microfilming

This optical comparator determines the line width and line density of drawings. Comparator readings can be used in conjunction with tables to inform a microfilm camera operator as to proper exposure of a film so that the lines of the drawings are reproducible through a lens system.

The comparator has a series of lines 1 of pre-calibrated width and grayness formed on transparent, comparator screen 2. Screen 2 is moved over a drawing until one of its lines 1 overlays part of line 3 of the drawing for width comparison. A variable illumination source of the comparator is adjusted until the grayness of the comparator line matches that of the drawing.

Width and grayness scale numbers are used in conjunction with a table to determine exposure. The light source can be varied in any suitable manner or a variable neutral density filter can be used with a fixed intensity light source.

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