发明名称 Digital halftoning combining dot size modulation screen with dot frequency modulation screen within a single image
摘要 An apparatus and method of producing enhanced digital imaging for printing data or reproduction process data (digital camera data) from the combination of dot size (amplitude) and dot density (frequency) halftone screens, whereof each halftone screen represents continuous "gray tone" (grey tone) input image levels. The method includes creating a dot frequency modulation (FM modulation-dispersed dot technique) in lighter areas which otherwise would require a dot size which is below user definable "dot size limit". This dot frequency modulation randomly deletes dots from the dot area modulation screen (AM modulation-cluster dot technique) in these lighter areas. The percentage of frequency modulation is graduated over the range of gray values which reduces objectionable visual transitions. Enhanced overall definition over the gray scale range of 0 to 100 percent (i.e., where 100 is equal to "255" in 8-bit environment), specifically over the more visually perceptive gray scale range of 0 to 20 (i.e., out of 0-255 value) is achieved. The apparatus which implements the method is positioned intermediate a desktop publishing system and an image setter.
申请公布号 US5892588(A) 申请公布日期 1999.04.06
申请号 US19970942795 申请日期 1997.10.02
申请人 PROFESSIONAL SOFTWARE TECHNOLOGIES INC. 发明人 SAMWORTH, MARK R.
分类号 H04N1/40;H04N1/405;(IPC1-7):H04N1/40;B41J15/00 主分类号 H04N1/40
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