Noar and Shamir presented the concept of visual cryptography. Many researches following it go down the same track: to expand the secret pixels to blocks. As a result, the size of the secret image becomes larger, and the quality of the expanded secret image becomes worse. In order to prevent the pixels from expanding, Yang has proposed his probability-based visual secret sharing scheme, where the concept of probability is employed to pick out pixels from the black or white sets. In this paper, we shall propose a new scheme that is a modified version of Yang’s scheme. Our experimental results show that we can obtain better recovered image quality with high contrast.
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