Lossless Coding of Error Diffused Images by Inverse Halftoning with Viterbi Decoding

Abstract

A lossless coding of an error-diffused image by coding a multi-level image generated through inverse halftoning process using soft decision method is proposed and studied. In order to study a coding method of error-diffused image in the domain of multi-level, it is necessary to find the image having minimum entropy, so far as it can produce exactly same error-diffused image at the receiver. To find such a multi-level image, we applied the idea of Viterbi decoding in inverse error diffusion process. The result shows that the multi-level image derived by proposed method has about 10-19% less entropy than the bi-level halftone image and 27-49% less entropy than that of the original multi-level image, which means that the multi-level image coding could be a good method for coding error-diffused image.