Abstract
A new halftone algorithm is described. The algorithm is designed for implementation on a parallel architecture in order to provide fast, progressive coding of moderate-resolution images. The design is based on a multiresolution, hierarchical, pyramidal structure. At each pyramid level, the binarized image is compared with the original, gray-tone image over a successively larger window of pixels for calculation of a weighted averaged error. Within each level, selected binarized pixels are tested for possible changes in the binary assignment. The binary assignment is changed if the change results in a lower average error over the entire window. Varying the selection of test pixels can cause the same process to provide clustered-dot patterns and dithering. A comparison of performance with the best implementation of the error-propagation algorithm is presented visually. Quality is compared also in terms of isotropy of the texture and the appropriate blue-noise characteristics in areas of uniform gray tone. The benefits of this algorithm are realized with moderate-resolution display of the order of 512 dots × 512 dots. The processing can be carried out on smaller blocks since the results can be combined without any visible seams or edge effects.
© 1991 Optical Society of America
Full Article | PDF ArticleMore Like This
David L. Neuhoff, Thrasyvoulos N. Pappas, and Nambi Seshadri
J. Opt. Soc. Am. A 14(8) 1707-1723 (1997)
J. Sullivan, R. Miller, and G. Pios
J. Opt. Soc. Am. A 10(8) 1714-1724 (1993)
Theophano Mitsa and Kevin J. Parker
J. Opt. Soc. Am. A 9(11) 1920-1929 (1992)