Image secret sharing method with two-decoding-options: Lossless recovery and previewing capability

Visual cryptography scheme (VCS) is a research area in image secret sharing, where one can easily stack shadow images and decode a black-and-white secret image through the human visual system without computation. Although VCS does not provide a competitive reconstruction quality, its stacking-to-see property clearly has the intended applications. To develop the ease of decoding of VCS and simultaneously overcome its weakness, Lin et al. recently proposed a novel two-in-one image secret sharing scheme (TiOISSS) with two decoding options based on VCS and a polynomial-based image secret sharing scheme (PISSS). In this TiOISSS, the first decoding stage has the stacking-to-see property to preview a vague image, and the second decoding stage is to obtain the original gray-level secret image. In this paper, we design a new TiOISSS by combining VCS and PISSS in a different way; in specific, our new scheme reduce shadow image size, and is more suitable for faster transmission within a distributed multimedia system.