Scalable Secret Image Sharing With Smaller Shadow Images

In 2007, Wang and Shyu proposed a scalable secret image sharing scheme in which three sharing styles, namely the multisecret, priority, and progressive modes, are designed to encode an image with diverse revealing effects. Their scheme is a (2, n ) sharing method where each generated shadow image is half size of the original image. This letter proposes a general (t,n), 2 ?? t ?? n, scalable secret image sharing scheme with the same revealing effects. Notably, the size of each generated shadow image is only (2n-t)/n ² times of the original image. The smaller size of the generated shadow images makes their transmission and storage more efficient.