Analysis and design of visual secret sharing scheme for gray image

Abstract

Existing gray visual secret sharing (GVSS) convert the original image into black-white binary image for processing, which causes the pixel information loss problem. For this purpose, a kind of GVSS based on gray superposition was proposed. For each gray-scale pixel, the corresponding encoding matrix was designed to generate gray share image. On this basis, the schemes for (2, 2), (2, n), (n, n) threshold structures were designed. Compared with the existing schemes, the proposed scheme effectively reduces pixel expansion and achieves the perfect reconstruction of gray secret images.

Keywords

• visual secret sharing
• gray image shares
• grayscale superposition
• lossless decoding