Halftone visual cryptography with minimum auxiliary black pixels and uniform image quality

In halftone visual cryptography scheme (HVCS), a secret image can be embedded into halftone shares with meaningful information of the cover images. Meaningful shares are significant since the efficiency of shares management will be increased and the suspicion of secret image encryption will be decreased. In this paper, we propose an HVCS construction method with minimum auxiliary black pixels (ABPs) distributed homogeneously, which is realized via embedding secret image into meaningful shares in the halftoned processing of the cover images by error diffusion. Secret information pixels (SIPs) are fixed in parallel and separated maximally from each other before the halftoned processing. The proposed scheme obtains admirable visual quality and some preferable advantages compared with related meaningful VC schemes (VCSs). Simulations and comparisons show the advantages and effectiveness of the proposed scheme.