| 摘要 |
PROBLEM TO BE SOLVED: To apply suppression or other processing to noisy dots which are produced in a background area. SOLUTION: This image processing unit is provided with a weight sum circuit 16, that takes the weight sum of errors in plural surrounding pixels that have already been quantized, an addition circuit 10 that adds the error weight sum and the received image signal of a concerned pixel, a background level detection circuit 17 that detects a background level, a character level detection circuit 19 that detects a character level, a limiter circuit 11 that limits an output of the addition circuit between two output levels of the background level detection circuit and the characteristic level detection circuit, a quantization circuit 12 that calculates threshold level from the outputs of the background level detection circuit and the characteristic level detection circuit to quantize an output of the limiter circuit, a multiplexer circuit 13 that multiplexes an output of the quantization circuit on the output of the background level detection circuit and the characteristic level detection circuit, and a difference circuit 14 that calculates the difference between the output of the multiplexer circuit and the output of the limiter circuit to obtain an error. As a result, the processing unit can suppress noisy dots.
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