<title>Error diffusion with vivid color enhancement and noise reduction</title>

Abstract

A novel error diffusion technique with vivid color enhancement and noise reduction has been developed to achieve high quality, high resolution color ink jet printing. Conventional error diffusion produces halftones with worm-like and salt-and-pepper-like noises. Each halftoned pixel may be one of the 8 colors: RGBCMYKW. Depending on the printing device characteristics (including printer dot size, registration, resolution, ink, and media), color interference between the 8 possible colors may occur. This color interference produces visible salt-and-pepper noise. In order to remove the noise, we classify the 8 colors into three clusters. Each cluster contains a set of harmonic colors. We exclude non-harmonic color halftones to be mixed. Any smooth color area in an input image uses a cluster (i.e., a set of colors) to make the halftone color more vivid and to minimize the non-harmonic color interference. In the error diffusion processing, inter-frame information between RGB plans are used to enforce the color cluster rules to achieve no salt-and-pepper noise and more vivid color halftones. Experimental results are provided to show the effectiveness of the technique.