期刊名称：International Journal of Computer Science and Information Technologies
电子版ISSN：0975-9646
出版年度：2014
卷号：5
期号：5
页码：6275-6277
出版社：TechScience Publications
摘要：Conventional visual secret sharing schemes generate noise-like random pixels on shares to hide secret images. It suffers amanagement problem, because of which dealers cannot visually identify each share. This problem is solved by the extended visual cryptography scheme (EVCS), which adds ameaningful cover image in each share. However, the previous approaches involving the EVCS for general access structures suffer from a pixel expansion problem. In addition, the visual cryptography (VC)-based approach needs a sophisticated codebook design for various schemes. In this paper, a novel method of VC is presented for halftone images which represent the resultant image in the same size as the original secret image Contrast the visual information based on pseudo randomization and pixel reversal using sigmoid function is also proposed
