Browse Prior Art Database

Gray Tone Generating for Facsimile Reproduction in a Photoprinter

IP.com Disclosure Number: IPCOM000074374D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Martin, VC: AUTHOR [+2]

Abstract

Shown is apparatus for reproducing a facsimile of a photograph with a photoprinter. Photoprinters are used widely for character printing. This apparatus adds the capability of reproducing pictorial information directly with the photoprinter. The pictorial information is coded by the apparatus shown in area 10. Picture 12 is coded by using a facsimile scanner 14 to convert the picture to an analog gray-level signal. The facsimile scanner scans the picture 12 with successive horizontal scans. The output of the facsimile scanner is an analog signal over line 16 which indicates the gray level at any instantaneous time during a horizontal scan across the picture 12. Information over line 18 out of the scanner 14 indicates the beginning and end of each horizontal scan line.

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Gray Tone Generating for Facsimile Reproduction in a Photoprinter

Shown is apparatus for reproducing a facsimile of a photograph with a photoprinter. Photoprinters are used widely for character printing. This apparatus adds the capability of reproducing pictorial information directly with the photoprinter. The pictorial information is coded by the apparatus shown in area
10. Picture 12 is coded by using a facsimile scanner 14 to convert the picture to an analog gray-level signal. The facsimile scanner scans the picture 12 with successive horizontal scans. The output of the facsimile scanner is an analog signal over line 16 which indicates the gray level at any instantaneous time during a horizontal scan across the picture 12. Information over line 18 out of the scanner 14 indicates the beginning and end of each horizontal scan line. The analog gray-level signal is converted to a digital signal by the analog to-digital converter 20. A six-bit binary word could be used for each sampling interval of the gray level 16. This would provide 64-levels of gray for a given interval in the analog signal. This six-bit binary word is passed to translator 22. Translator 22 also receives the beginning and end of horizontal scan line indication from the facsimile scanner 14. The translator 22 takes each digital gray-level word and converts it into a half-tone character code.

A character code is simply a "rd that calls for a photoprinting system to print a particular symbol. In the case of half-tone character codes, the symbol to be printed might be a black dot in the center of an area of space. As the gray level is intensified, the black dot would be enlarged. There would be a character code for each size black dot. Of course, any shape symbol might be used, such as for example, diamonds, squares, or rectangles. Thus, the half-tone character code would specify a particular shape symbol and the size of that symbol. Therefore, the output of translator 22 is a string of half-tone c...