Introduction - If you have any usage issues, please Google them yourself
Two common drawbacks of the visual cryptography
scheme (VCS) are the large pixel expansion of each share image
and the small contrast of the recovered secret image. In this paper,
we propose a step construction to construct VCS and VCS
for general access structure by applying (2,2)-VCS recursively,
where a participant may receive multiple share images. The proposed
step construction generates VCS and VCS which
have optimal pixel expansion and contrast for each qualified set
in the general access structure in most cases. Our scheme applies
a technique to simplify the access structure, which can reduce the
average pixel expansion (APE)