Patent ID: 7339706
Filing Date: 2008-03-04
Classification: H04N

Abstract:
1. An error diffusion processing circuit for carrying out error diffusion processing of input image signals of pixels comprising: a quantizing unit which quantizes an input image signal of each pixel to generate an output image signal having a number of gray tones smaller than that of said input image signal; a subtracter which generates an error signal based on a difference between said input image signal and said output image signal; a filtering unit which generates a plurality of filtered error signals from said error signal, said plurality of filtered error signals including a feedback error signal to be spatially diffused into a neighboring pixel next to each pixel; a first adder which adds, to said feedback error signal, an input image signal of said neighboring pixel to be input into said quantizing unit; a noise signal source which generates a noise signal; and a second adder which adds said noise signal to any one of: said input image signal, said output image signal, said error signal, and said feedback error signal, wherein said noise signal is fed in a feedback loop including said quantizing unit, said subtracter, said filtering unit and said first adder.