Browse Prior Art Database

High Resolution Sensing Optics

IP.com Disclosure Number: IPCOM000093951D
Original Publication Date: 1966-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

van Praag, A: AUTHOR [+2]

Abstract

High-resolution sensing optics for multitrack character sensing comprises lamp 10 illuminating slit 11 through condensor lens 12. Slit 11 is scratched in the opaque cover on one surface of beam-splitting prism 13. Objective lens 14 forms reduced image 15 of slit 11 on moving document 16 which carries printed character 17. One column of the character is thus illuminated at a time. Re-emitted light from column 15 is again collected by objective 14 and is focused on a second slit 18, after reflection against beam-splitting inner surface 19 of prism 13. Elongated solar cell 20, located at slit 18, is divided by parallel incisions into a plurality of individual cells. Each cell receives brightness information from a different area element of column 15.

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High Resolution Sensing Optics

High-resolution sensing optics for multitrack character sensing comprises lamp 10 illuminating slit 11 through condensor lens 12. Slit 11 is scratched in the opaque cover on one surface of beam-splitting prism 13. Objective lens 14 forms reduced image 15 of slit 11 on moving document 16 which carries printed character 17. One column of the character is thus illuminated at a time. Re- emitted light from column 15 is again collected by objective 14 and is focused on a second slit 18, after reflection against beam-splitting inner surface 19 of prism
13. Elongated solar cell 20, located at slit 18, is divided by parallel incisions into a plurality of individual cells. Each cell receives brightness information from a different area element of column 15. A multiplicity of sensing track signals is thus generated and fed to recognition logic 21.

In this sensing apparatus the use of dual slits 11 and 18 diminishes generation of noise by a creeping light phenomenon. If document 16 is illuminated directly by lamp 10 with elimination of slit 11, a lower brightness is measured in white background area elements close to a vertical stroke of the character as compared to measurements in spots distant from the character. Not all the light energy reflected from a given spot is incident in that same spot, there being also a contribution from adjacent illuminated spots. The contribution falls off in the proximity of a printed line. This contribution is...