Adaptive Ordered Dither

Ordered dither (C. N. Judice, J. F. Jarvis, and W. H. Ninke, inProceedings of the S.I.D. 15, 4(Fourth Quarter),1974,pp. 161–169.) is an efficient and widely used halftoning technique. One disadvantage with this method is that it produces blurred images. Recently, a space-filling curve ordered dithering approach (Y. Zhang, submitted for publication.) has been proposed that improves the ordered dither in image quality by generating clustered dot patterns along a space-filling curve over the image. In this method the cluster size is fixed in the process of halftoning. This paper presents a new ordered dithering method, called adaptive ordered dither, that does halftoning by using a space-filling curve to perform an adaptive variation of the cluster size. Experimental results demonstrate that the new method can significantly improve the space-filling curve ordered dither in revealing image details.