Halftone Visual Cryptography Through Error Diffusion

This paper considers the problem of encoding a secret binary image SI into n shares of meaningful halftone images within the scheme of visual cryptography. We extend our previous work on halftone visual cryptography and propose a new method that can encode the secret pixels into the shares via simple error diffusion. The noise introduced by encoded secret pixels is totally diffused away to neighboring pixels and pleasing halftone shares can be achieved. The secret image can be clearly decoded without showing any interference with the share image. The security of our method is guaranteed by the properties of visual cryptography.