Color Zero-Watermarking Algorithm for Medical Images Based on BEMD-Schur Decomposition and Color Visual Cryptography
Table 1
The Repetition code.
Algorithm 1 Color zero-watermarking algorithm
Input: Color host image of size , Color logo of size .
Output: Color zero Watermark
1: Read a color host image of size and a color logo of size .
2: The color host image is partitioned into R, G, and B components to obtain ,, and . The color logo image is extracted into R, G and B components to obtain ,, and .
3: for c = R, G, B do
4: To increase the security of watermark encrypt the watermark by Arnold scramble using (5).
5: Perform DWT and BEMD on to obtain , and sum to obtain using (7).
6: Divide into nonoverlapping blocks of size to sub-block using (8).
7: for j = 1 to m do
8: for j = 1 to n do
9: For each sub-block using Schur decomposition to obtain sub-block max singular value using (9) and (10).
10: end for
11: end for
12: Convert of each sub-block into a binary form to generate a binary feature matrix using (11).
13: According to form gray master share using (12).
14: Perform the CVC mapping rule on and to obtain the gray ownership share using (14).
15: end for
16: Generate color master image by overlapping gray master shares ,, using (13).
17: Generate color ownership share by overlapping gray ownership shares ,, using (15), and as color zero watermark.
