On Perceptually Consistent Image Binarization

Compared with gray images, bi-level images have only two values for each pixel and are more convenient for transmission and storing. Hence, they are very useful in many practical applications such as in image printing and display. Of various image binarization methods, error diffusion is a popular one that can produce perceptually consistent halftone images. However, most of the existing error diffusion techniques have not given rigid theoretical foundation or explicit theoretical derivation, and most of their diffusion domains and diffusion weights are constant, which make them inconvenient to be used and inefficient in some practical applications. In this paper, a new error diffusion scheme for image binarization is derived and established based on the analysis of features of the human visual system (HVS) and the heat transfer theory, where the local image information and the local pixels' value distribution are kept stable or little changed during the binarization process. As a result, the overall visual quality of binarized images can be kept perceptually similar to the original ones. Experiments are conducted and convincing results are acquired.