Article ID Journal Published Year Pages File Type
531566 Pattern Recognition 2008 16 Pages PDF
Abstract

A (t,n)(t,n) visual cryptography scheme (VCS) encodes a secret image into n shadow images (shadows) distributed among n participants. When any qualified set of at least t participants stack their shadows, the secret image can be visually revealed. The first VCS proposed by Naor and Shamir was only designed for encrypting a black-and-white secret image; subsequently, some colored VCSs (CVCSs) for sharing colored images were proposed to enhance the applicability. In CVCSs, we usually use several color subpixels to represent a secret pixel where the number of subpixels is referred to as the pixel expansion. Generally, the CVCS requires a larger pixel expansion to produce more colors; however, this expansion will increase the shadow size. We therefore study the additive color mixing in a probabilistic way and propose a new CVCS whose pixel expansion is fixed and improves on the previous CVCSs, at the price of reducing the contrast quality to certain level.

Related Topics
Physical Sciences and Engineering Computer Science Computer Vision and Pattern Recognition
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