On Visual Cryptography of Multiple Secret Images

• Main Authors: Li, Fong-Jheng, 李豐政
• Other Authors: Lin, Ja-Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/k3qv8e

碩士 === 國立交通大學 === 多媒體工程研究所 === 102 === This master’s thesis proposes three schemes on visual cryptography of multiple secret images sharing: (2,2) model, constrained (2,3) model, and folding model. In the (2,2) model, we present two different schemes : 1) Multiple types of stacking: this method encodes twelve secret images into two transparencies. We can get twelve secret images respectively by eight different stacking types. 2) High hiding capacity: for four given secret images, two transparencies are produced. Stacking in different manners, we can decode four secret images respectively. Total space needed is smaller than the bits of total secret images. In constrained (2,3) model, the method encodes four secret images into three transparencies. We only can decode secret images by stacking the most important transparency with either one of the two other transparencies. This method can be extended into (2,k) model. Finally, in the folding model, we fold down a transparency, and then stack with the other to decode secret images.