Browse Prior Art Database

Implicit Optical Filtering

IP.com Disclosure Number: IPCOM000093955D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Brown, AW: AUTHOR

Abstract

Implicit optical filtering provides an arrangement by which selected portions of a scanned document can be automatically ignored. Such is effected by coloring such portions to produce a spectral reflectivity which lies outside the frequency response of the image detector. The same result can be attained by explicit filtering by inserting colored filters between the scanned document and the image detector.

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Implicit Optical Filtering

Implicit optical filtering provides an arrangement by which selected portions of a scanned document can be automatically ignored. Such is effected by coloring such portions to produce a spectral reflectivity which lies outside the frequency response of the image detector. The same result can be attained by explicit filtering by inserting colored filters between the scanned document and the image detector.

Document 2 contains information 3 which is sensed by image detector 1 which can be a vidicon. Grid 4 and border 5 represent typical information on document 2 which are not to be sensed. Image detector 1 has a selective frequency response. By printing grid 4 and border 5 in colors which produce spectral reflectivities outside the frequency response of image detector 1, grid 4 and border 5 are not sensed as document 2 is scanned.

Explicit filtering can also be used to accomplish the same result. This is realized by inserting interference filters 6 between scanned document 2 and image detector 1.

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