Image Sharing with Steganography and Authentication - Visual Cryptography and Secret Image Sharing - page 448

FIGURE 16.29
The visual quality of the reconstructed grayscale image.
various schemes. These results reveal that, among Lin-Tsai's scheme, Yang et
al.'s scheme, and the proposed scheme, our scheme provides the best authen-
tication capability. In Lin-Tsai's scheme, there is only one pixel for each block
undergoing parity check. As a result, the authentication capability is not very
good.
In Yang et al.'s scheme, four pixels of each block all undergo the procedure
using a hash function. However, their final check bit is computed by using an
XOR operation. So, their probability of successful authentication should re-
main at 50%. In our scheme, two check bits are adopted and the probability
of successful authentication could be increased to 75%. On the other hand,
compared with Chang et al.'s scheme, in which four check bits are adopted
and authentication is implemented by using CRT (the Chinese Remainder
Theorem), our proposed scheme has a lower detection ratio while maintaining
lower computation complexity. However, because the set of shadows and the
reconstructed secret image are generated through simple operations, no com-