| 摘要 |
PURPOSE:To attain binary-coding taking the resolution characteristics of the reading system into consideration, by discriminating white and black picture for objective picture elements, based on the level of picuture elements before and after the objective picture element and its level. CONSTITUTION:An A/D conversion circuit 1 quantizes an analog picture signal (a). A latch circuit 2 latches a quantized picture signal 3 for for each one picture element and inputs an output (d) to a latch circuit 3. The latch circuit 3 is latched at each one picture element in a timing delayed for a prescribed time from the latch timing of the circuit 2. A digital comparator 4 compares the output (d) of the circuit 2 with an output (e) of the circuit 3. A latch circuit 5 latches an output (f) of the comparator 4. A discrimination circuit 6 performs discrimination of white and black signals depending on an output (g) of the circuit 5, an output (b) of the comparator 4, the output (e) of the circuit 3 and an output (i) of a line memory 7. In this case, the discrimination is done by taking the level for the preceding and succeeding picture element as well as the level itself of the guantized picture signal (c) of the picture element to be discriminated, into consideration. |
