| 摘要 |
PURPOSE:To convert the low picture element density signal into the high density signal by dividing the sampled picture element of the quinary density level into four minor picture elements, detecting the maximum density level picture element as well as the ambient picture element density level distribution adjacent to the noticing picture element and then deciding the black and white level states according to the detection result. CONSTITUTION:Input signal VIN undergoes the A/D conversion and is then sent to picture element memory S9 of shift register SR for memorization via the signal line of the 1-picture element and 3-bit structure. The contents of memory S9 are transferred in sequence to picture element memories S8 and S7 each. At the same time, signal VIN is transferred also to 1-line memory BM1. In the same way, signal VIN entered memory S6 is sent to 1-line memory BM2. The contents of memories S9-S1 receive the comparison operation at comparison arithmetic circuit CMP and also supplied to maximum value detector circuit MX for decision. Comparison arithmetic outputs C1 and C2, output M or circuit MX and the signal of memory S5 are supplied to the address of ROM to decide density level output O1-O4. These output O1-O4 are sent to parallel-serial converter circuit PS to be converted into the serial signals suited for transmission, thus obtaining output signal VOUT. |
