INVERSE HALF-TONING VIA MAP ESTIMATION

There has been a tremendous amount of research in the area of image ha lftoning, where the goal has been to find the most visually accurate r epresentation given a limited palette of gray levels (often just two, black and white), This paper focuses on the inverse problem, that of f inding efficient techniques for reconstructing high-quality continuous -tone images from their halftoned versions, The proposed algorithms ar e based on a maximum a posteriori (MAP) estimation criteria using a Ma rkov random field (MRF) model for the prior image distribution, Image estimates obtained with the proposed model accurately reconstruct both the smooth regions of the image and the discontinuities along image e dges, Algorithms will be developed and example gray-level reconstructi ons will be presented generated from both dithered and error-diffused halftone originals, Application of the technique to the problems of re screening and the processing of halftone images will be shown.