Stochastic threshold array generating system and method for generating an error map for image rendering

摘要

An image rendering system, for generating discrete tone image data representing a continuous-tone image for rendering by a rendering device, the image rendering system includes a stochastic threshold array generating arrangement and an image data processing section. The stochastic threshold array generating arrangement generates a plurality of stochastic threshold arrays from a random seed pattern that have been subsequently optimized to reduce image artifacts in the rendering of tones. Each pattern is optimized to reflect (i) a selected trade-off between grain and possible mottle in the rendered image, (ii) distortions introduced by the rendering device in rendering an image defined by the pattern and an observer in viewing the image, and (iii) boundary effects so that the paterns, when tiled together, have optimal visual characteristics proximate their respective edges. The image data processing section processes the continuous tone image data in relation to the stochastic threshold arrays generated by the stochastic threshold array generating arrangement. The image data processing section may be used to either randomly tile, or tile in an ordered way, the stochastic threshold arrays over the continuous-tone image data and generates the discrete tone image data in response to correspondingly positioned pixels of the continuous-tone image data and threshold values of the stochastic threshold arrays. IMAGE