Contrast-Improved Visual Cryptography for General Access Structure
Xuehu Yan, Yuliang Lu, Lintao Liu, Song Wan, Wanmeng Ding, Hanlin Liu · 2016
Random grid (RG)-based visual secret sharing (VSS) has neither pixel expansion nor codebook design. VSS for general access structure (GAS) has wider applications compared with (k, n) threshold VSS. Previous RG-based VSS schemes for GAS have the limitations of "all-or-nothing" or low visual quality. In this paper, we propose a progressive VSS (PVSS) scheme for GAS with improved visual quality based on RG. The different regions of the secret image and corresponding generated random bits, which are classified into three parts, are employed to improve the visual quality of the revealed secret image and to gain GAS with progressive property. In addition, our scheme has neither pixel expansion nor codebook design due to RG. The effectiveness of the proposed scheme are shown in terms of experimental results and analyses.