| 摘要 |
PURPOSE:To pack a solid black area in a uniform alternate black and white pattern and to prevent central blanking, by supplying alternate black and white picture element signals to a line memory when the run length of black picture elements of compressed data to a restoring device exceeds a prescribed value. CONSTITUTION:Data to be compressed are applied to a coincidence circuit 11 through a register 10, an FF15, and a comparing circuit 13, and the circuit 11 checks coincidence with the value of a counter 12 to supply an address to a logical circuit and a line memory 30. The circuit 13 checks whether the difference between the compressed data and the value of the counter 12 exceeds a predetermined value or not, and when not, a multiplexer 19 selects and writes a signal (a) from the FF15 in the memory 20. When the difference is greater than the prescribed value, signals (b) and (c) from the logical circuit are determined by the least significant digit bit LSB of a counter 14 to write the signals (b) and (c) in the memory 20 alternately at intervals of one line. Thus, a solid black area is filled up in an uniform alternate black and white pattern to prevent central blanking. |
