| 摘要 |
PURPOSE:To obtain photoelectric conversion for the characteristic of an original pattern on a document with fidelity in high speed scanning, by referencing a signal after at least one sampling ahead the sampling period for the selection of an output signal of a sampling circuit having white or black priority. CONSTITUTION:A signal S1 binary coded in white and black from a photoelectric converter and a clock signal S2 for sampling and shift are applied to sampling circuits 1a and 1b. The circuit 1a is a black priority circuit which takes the entire period as black if a little of black component is present during the sampling period and the circuit 1b is the white priority circuit. A selection signal generating circuit 3 references a signal after at least one sampling ahead the sampling period of the circuits 1a and 1b and decides if either of the outputs of the sampling circuits of the circuits 1a and 1b is to be the signal for the sampling period. The output of the circuit 3 selects 2 one of outputs S3 and S4 of the sampling circuits. |
