Quantization and multilevel halftoning of color images for near-original image quality

Algorithms are investigated for the printing or display of color images at near-original image quality with a minimum number of output colors. Each algorithm consists of a quantizer that is used possibly in conjunction with halftoning. We consider both image-independent and image-dependent quantizers implemented in RGB or in the uniform color space L*u*υ*. The halftoning techniques that we use are multilevel extensions of error diffusion and ordered dither. Image quality resulting from the use of these algorithms is measured by subjective evaluation.