| 摘要 |
PURPOSE:To realize a virtually sharp reproduction for a coarse picture element original, by giving an A/D conversion to the reading signal and then selecting the dither pattern data stored in the ROM by the conversion signal and with the address control to then deliver the pattern data with every reading picture element. CONSTITUTION:The A/D comparator 104 contains a quadrivalent comparator and divides the output Vout of the CCD103 into the five regions with the four threshold values. The address encoder 105 produced the address data for ROM1 and ROM2 of the ROM106 and 107 by the output level of the comparator 104, and the information equivalent to the dither pattern is stored previously into the ROM106 and 107. This storage value is read out by designating the corresponding address of the ROM. The memory 1(108) and memory 2(109) read the dither information of the ROM1 and 2 to then write and store them successively. The gate 110 switches the outputs of the memories 1 and 2 alternately and then sends them to the signal operating part 111. At the part 111, the reversal, contraction and enlargement, and other processes are carried out for the picture. Then a luminance modulation is given to the laser beam by the output signal of the part 111. |
