Improving Image Quality In Extended Visual Cryptography For Halftone Images With No Pixel Expansion

Visual cryptography is a secret sharing scheme that divides secret images into shares such that, when the shares are superimposed, a hidden secret image is revealed. In extended visual cryptography, an extra security is provided by giving cover images to the shares. However, in either case, loss of resolution, contrast, and image size expansion are challenging problems that the researchers are facing. In this paper, we propose a method for processing halftone images that improves the quality of the recovered images and also avoids pixel expansion. The resulting scheme maintains the perfect security of the original extended visual cryptography approach and also provides a better result.