| 摘要 |
PURPOSE:To encode a dither picture signal high efficiently when a specific pattern of white and black picture elements are generated, by encoding a mode code for displaying this pattern, times of the successive generation of the pattern. CONSTITUTION:An original 1 is read by a sensor 3, whose output is stored in a line memory 4. Then, an encoding circuit 5 reads out a picture element signal out of the line memory 4 to count the continuation length (RL) of white or black picture elements, and a comparator 8 detects whether the RL is equal to 1 or 3. When the RL is equal to 1 or 3, the RL before the preceding one, delayed by two stages of delay elements 9 is compared with the current RL by a coincidence circuit 10. When the both are equal, an identical-pattern continuation counter 11 goes up by one. When not, the value of the counter 11 is compared by the 1st threshold value comparator 12 with some threshold value and when it is greater than the threshold value, namely, when the same pattern continues long, a mode code for the same pattern and the value of the counter 11 are encoded and sent out. |
