Abstract
Visual cryptography is a technology that hides a secret image in other images and the hidden image can be decoded by the human visual system. A conventional method based on error diffusion method can product two high quality binary halftone images from two gray-scale images and we can decoded a gray-scale secret image by superposing these halftone images. In this paper, we consider about intensity transform to generate binary halftone image for high-quality decoding of a secret image in the conventional method. We added histogram equalization to conventional method and evaluated quality of images. As a result, we could decode the secret image more high-quality than conventional method.
