Visual cryptography is one of those unusual cases that kind of looks like a good idea, but it turns out is fraught with problems. The idea is straightforward enough — an image to encrypt is sampled ...

Visual cryptography and secret image sharing constitute a family of techniques for dividing an image into multiple concealed components, or shares, such that only a authorised assembly of those shares ...

In this paper, the authors investigate the problem of varying the size of dots in the digital half toning processes. The reproduction of grey scale images in bi-level graphic displays is achieved ...