In this paper two methods for (2, 2) and (2, 3) visual cryptographic scheme(VCS) is proposed. The first scheme considers 4 pixels of input image at a time and generates 4 output pixels in each share. As 4 output pixels are generated from 4 input pixels dimension and aspect ratio of the decrypted image remain same during the process. The second scheme considers 2 pixels (1 block) of input image at a time and generates 3 output pixels in each share. Here probability of 1/3 for black pixel is maintained in each share. The scheme improves the contrast of output image. The dimension of revealed image is increased by 1.5 times in horizontal direction and remains same in vertical direction.
Chakraborty, Ujjwal; Pau, Jayanta l Kumar; and Mahapatra, Priya Ranjan Sinha
"Design and Implementation of a (2, 2) and a (2, 3) Visual Cryptographic Scheme,"
International Journal of Computer and Communication Technology: Vol. 1
, Article 11.
Available at: https://www.interscience.in/ijcct/vol1/iss3/11