Visual Cryptography from Halftone Error Diffusion - Visual Cryptography and Secret Image Sharing - page 24

contrast loss of the decoded image is worse. It is observed that the contrast
of Figure 1.11(d) is lower than that of Figure 1.10(d).

(a) (b)

(c) (d)

FIGURE 1.12
(a){(c) Shares of the 3-out-of-3 scheme using the second method, q = 16.
(d) Decoded image by shares (a){(c), = 1=16. (Reprinted with permission
from IEEE Trans. Inf. Forensics Security, vol. 4, no. 3, pp. 383{396, Sep. 2009
c IEEE 2009).

In the following, we present the halftone shares generated by using the
second construction method. The performance of the second method is evalu-