Image signal processing apparatus

摘要

A correcting device corrects a multi-level image signal of a pixel of interest in accordance with corrective data. A binarizing device binarizes an output signal of the correcting device. A logic device receives an output signal of the binarizing device. A feedback device feeds an output signal of the logic device, which corresponds to at least two feedback pixels immediately preceding the pixel of interest in a scanning direction, back to an input side of the logic device. A calculating device derives a difference between an output signal of the logic device and the output signal of the correcting device, and generates the corrective data on the basis of the derived difference. An output signal of the logic device is a pseudo halftone image signal. The logic device operates as follows. A black-level signal is outputted as a signal of the pixel of interest when the output signal of the logic device which corresponds to the feedback pixel closest to the pixel of interest is black and the output signal of the logic device which corresponds to the other feedback pixel is white. A signal equal to the output signal of the binarizing device is outputted as a signal of the pixel of interest in other cases. A white-level signal is outputted as a signal of the pixel of interest when the output signal of the logic device which corresponds to the feedback pixel closest to the pixel of interest is white and the output signal of the logic device which corresponds to the other feedback pixel is black. A signal equal to the output signal of the binarizing device is outputted as a signal of the pixel of interest in other cases.