Blind and Secured Adaptive Digital Image Watermarking Approach for High Imperceptibility and Robustness

. 2021 Dec 8;23(12):1650. doi: 10.3390/e23121650

Algorithm 1 Watermark embedding.

Require:
Cover image (C), Watermark (W), m, s
Ensure:
Watermarked image ( $C_{1}$ )
1:
Apply 1-IWT to C, to obtain LL, LH, HL and HH. Select LH and HL for embedding.
2:
Divide $L H$ and $H L$ into $4 \times 4$ non-overlapping blocks.
3:
Find entropy for $4 \times 4$ non-overlapping blocks and store it in vector $V$ .
4:
Apply SVD transform on LH and HL, to obtain $U_{L H}, S_{L H}, V_{L H}, U_{H L}, S_{H L}, V_{H L}$ . Select $S_{L H}$ and $S_{H L}$ for embedding.
5:
Select a block having a low entropy value $(B_{L H} a n d B_{H L})$ for embedding.
6:
Encrypt the watermark image using the proposed encryption scheme
7:
Determine random embedding position $P_{1} (r o w)$ and $P_{2} (c o l)$ , using a BBS generator in selected block for embedding.
8:
Generate $α$ using the proposed intial scaling factor generation scheme
9:
For real time applications, skip Step 10 and move on to Step 11.
10:
Optimize $α$ using GA or ABC or FO algorithm using a following fitness function:

$F i t n e s s f u n c t i o n = \frac{(P S N R \times S S I M)}{α} + \frac{(N C \times B E R)}{α}$
11:
Embed $V_{o d d}^{1}$ in $B_{L H}$ and $V_{e v e n}^{1}$ in $B_{H L}$ using the following relation:

$B_{L H}^{1} (P_{1}, P_{2}) = B_{L H} (P_{1}, P_{2}) + α * V_{o d d}^{1}$

$B_{H L}^{1} (P_{1}, P_{2}) = B_{H L} (P_{1}, P_{2}) + α * V_{e v e n}^{1}$
12:
Apply inverse SVD and IWT to get the watermarked image ( $C_{1}$ ).