| 摘要 |
PURPOSE:To improve the quality of a reproduced image by storing data obtained by coding multilevel image data on a mixed image which contains a variable density image and a character image into binary data by using two kinds of threshold values, coding the character image area into a binary signal on the basis of a single threshold value, and coding the variable density image area into a binary signal on the basis of a dither threshold value. CONSTITUTION:The multilevel image data applied to an input terminal 133 is inputted to comparators 100-102 in parallel; the comparator 100 performs binary coding with a single threshold value and the comparator 101 performs binary coding with a single threshold value 3. The comparator 102, on the other hand, codes the multilevel image data into a binary signal with the dither threshold value 4. When a signal 28 for area decision making read out of a memory 121 is '1', a multiplexer 122 selects dither image data 15 read out of a memory 109 and outputs it. When '0', simple binary-coded image data read out of a memory 107 is selected and outputted from an output terminal 134 as binary-coded image data 16.
|
