Color hard copy apparatus having simplified analog-to-digital conversion with adjustable threshold levels
 A color hard copy apparatus converts an analog video signal of a still picture frame displayed on a color graphic display into binary video data to obtain a multicolor gradation picture. A single analog-to-digital converter samples the analog video signal a plurality of times at respectively different threshold levels, each threshold level being maintained constant during the sampling of the entire picture frame, to convert the analog video signal into corresponding binary video data. The binary video data are written in a picture memory at predetermined write-in addresses according to a predetermined multicolor gradation picture program, such as an organized dither program or a density pattern, and the binary video data are read out of the picture memory according to the predetermined multicolor gradation picture program to obtain binary picture data signals for use in printing a high-quality multicolor gradation picture corresponding to the desired picture frame displayed on the color graphic display. 
Seiko Instruments & Electronics Ltd.
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H04N H04N
inventional inventional
Yoshio Shinya Fumihiro Kaneo Kenichi
Shimada Watanabe Tanaka Yamaguchi Matsushima