Abstract: Visual cryptography schemes (VCSs) are techniques that divide a secret image into n shares. Stacking exactly n shares reveals the secret image. One VCS technique is the deterministic VCS (D-VCS), which suffers from the pixel expansion issue. This problem has been solved by probabilistic size invariant VCS (P-SIVCS); however, the visual quality of the revealed secret image produced by P-SIVCS is low. In D-VCS, a thin line is converted to a thick line and pixel expansion problem while it may not be visible in the revealed secret image created by P-SIVCS. In this paper, two new constructions are introduced for resolving the thin line problem with well visible quality and non expansion pixel by using image manipulation, D-VCS, a mixture of D-VCS and PSIVCS.

Keywords: Visual cryptography, Thin line problem, Pixel expansion

Pages: 212-221