Image processor using both dither and error diffusion to produce halftone images with less flicker and patterns

摘要

An image processing device has an error distribution unit, and a multiplier. The error distribution unit carries out an error distribution operation to artificially increase the number of shades to be displayed on a display. The multiplier multiplies an input signal by a multiplication coefficient, so that the input signal is separated into display data and error data along a bit boundary and the error distribution operation is carried out on the input signal. Further, a semiconductor integrated circuit has a dither pattern generator, an adder, and an error distribution unit. The dither pattern generator stores a plurality of dither patterns in advance and receives an input image signal, the adder receives the input image signal and a pattern signal from the dither pattern generator, and the error distribution unit carries out an error distribution operation on the output of the adder. Therefore, the image processing device can realize a smooth display characteristic for the entire range of input shades.