1. An imperceptible spatial domain color image watermarking scheme
Source : Journal of King Saud University - Computer and Information Sciences. Vol. 31, Iss. 1, pp , Jan
Authors : Jobin Abraham, Varghese Paul.
Speaker : Si-Liang He
Date : 2019/6/27
山東大學

2. Outline
Introduction Related work Proposed scheme Experimental results Conclusions

3. Introduction +
Logo watermark → →
Extraction

4. Related work - Simple Image Region Detector (SIRD)92 98 96 91 97
103 93 99
102
106 92 98 96 91 97
103 93 99
102
106 8 17 9 18
92− −97 +|97−98| =8

5. Proposed scheme - embedding flowchart

6. Proposed scheme – Watermark preprocessing
Image → + → 1 2 3 4 1 2
Binary watermark 3 4
Watermark
4 sub-image watermark

7. Proposed scheme – Watermark preprocessingB
R, G
k/4
k/2 k
k/8
k/4
k/2 1
k: the strength factor
sub-image watermark
Mask 1
Mask 2 92 98 96 91 97
103 93 99
102
106 94
102 98 91
101
106
103 95
104 96 99
k = 8, w = 1: 2 4 8
Selected 4×4 sub-block

8. Proposed scheme – Watermark preprocessing92 98 96 91 97
103 93 99
102
106 90 94 91 93
103 95
100
106 96 99
k = 8, w = 0: -2 -4 -8
Selected 4×4 sub-block
← Proposed scheme
← Only modify B

9. Experimental results
Salt & Pepper
Speckle
JPEG
Cropping

10. Experimental results
Payload
k = 8
k = 4
SSIM: Structural similarity

11. Experimental results [5] [8] Proposed method Watermark 64×64
Operating domain
Frequency
Spatial
Technique used
Four-level DWT
LSB
Speed of operation
Slow
Fast
Embedding color domain
RGB
Embedding color component
R, G, B B
PSNR (dB)
43.51 39
47.6
Adjustments for color variation No
Yes
[8] K. Liu, “Color image watermarking for tamper proofing and pattern based recovery,” IET Image Processing, Vol. 6, Issue. 5, pp.  , July
[5] H. Thien, O. Banos, S. Lee, Y. Yoon, L. Thuong, “Improving digital image watermarking by means of optimal channel selection,” Expert Systems with Applications, Vol. 62, pp.  , Nov

12. Conclusions
The mask 1 and mask 2 ensure the embedded bits are less distracting to the human eyes.
Due to only a quarter of the image space is utilized, the embedding capability is only 4096 bits.