Watermaking of images using Discrete Cosine Transform technique (DCT approach)

1. Presented by :
Anand Karandikar
Guided by:
Prof. G. G. Chiddarwar
Digital Image Protection Using
Adaptive Watermarking Techniques
3 May 20141
Digital Image Protection UsingAdaptive
WatermarkingTechniques

2. Overview:
DigitalWatermarking
Least Significant BitAlgorithm
Discrete CosineTransform Algorithm
Metrics for quality
LSB and DCT: Comparison
Conclusion
References
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Digital Image Protection UsingAdaptive
WatermarkingTechniques

3. Digital Watermarking: The concept
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WatermarkingTechniques

4. Digital Watermarking: Types
Visible watermark:
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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Fig.1.VisibleWatermark

5. Digital Watermarking: Types (cont.)
Invisible watermark:
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WatermarkingTechniques
Fig.2.InvisibleWatermark

6. Digital Watermarking: Classification
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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Fig.3.Classification ofWatermarking techniques

7. Least Significant Bit Technique
10110101 01001101 11001101
00010011 00010100 01001010
10110100 01001100 11001101
00010010 00010100 01001011
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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Fig.4.The LSB Substitution technique
Embed 001001
Secret Data
Original Image
encoded
format
Embedded
data

8. 8
Secret
data
Convert to bit stream
Conversion of data
Encode Data
Embedding
Extract
Decode Data
Original Source
Image
Load Source image
Convert to
stego image
Extracted
secret data
Digital Image Protection UsingAdaptive
WatermarkingTechniques
3 May 2014
Fig.5.The LSB Substitution procedure

9. Discrete Cosine Transform Algorithm
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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Fig.6.The DCT algorithm
Fragment
Use DCT
Block selection
Coefficient selection
EmbedWatermarks
Apply inverse DCT

10. Discrete Cosine Transform Algorithm
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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Fig.7.The DCT region
Low band
frequency region
Middle band
frequency region
High band
frequency region

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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Fig.8.The MBEC algorithm
Select the FM region
Select two points
say Pi(u1,v1) & Pi(u2,v2)
Pi(u1,v1)>=
Pi(u2,v2)
Encode 0 Encode 1
A
A
True False

12. 16 11 10 16 24 40 51 61
12 12 14 19 26 48 16 55
14 13 16 24 40 57 69 56
14 17 20
29 51 87 80 62
18 22 37 56 68 10
9
10
8
77
24 35 55 64 81 10
4
11
3
92
49 64 78 87 10
3
12
1
12
0
10
1
72 92 95 98 11
2
10
0
10
3
99
E.g.:
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Digital Image Protection UsingAdaptive
WatermarkingTechniques12
16 11 10 16 24 40 51 61
12 12 14 19 26 48 16 55
14 13 16 24 40 57 69 56
14 17 20
29 51 87 80 62
18 22 37 56 68 10
9
10
8
77
24 35 55 64 81 10
4
11
3
92
49 64 78 87 10
3
12
1
12
0
10
1
72 92 95 98 11
2
10
0
10
3
99
Fig.9.An illustration of DCT algorithm
Transform
Embed
Inverse
Transform
16 11 10 16 24 40 51 61
12 12 14 19 26 48 16 55
14 13 16 24 40 57 69 56
14 17 20
29 51 87 80 62
18 22 37 56 68 10
9
10
8
77
24 35 55 64 81 10
4
11
3
92
49 64 78 87 10
3
12
1
12
0
10
1
72 92 95 98 11
2
10
0
10
3
99
16 11 10 16 24 40 51 61
12 12 14 19 26 48 16 55
14 13 16 24 40 57 69 56
14 17 20
29 51 87 80 62
18 22 37 56 68 10
9
10
8
77
24 35 55 64 81 10
4
11
3
92
49 64 78 87 10
3
12
1
12
0
10
1
72 92 95 98 11
2
10
0
10
3
99

13. MBEC: The actual thing.
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Digital Image Protection UsingAdaptive
WatermarkingTechniques13
16 11 10 16 24 40 51 61
12 12 14 19 26 48 16 55
14 13 16 24 40 57 69 56
14 17 20 29 51 87 80 62
18 22 37 56 68 109 108 77
24 35 55 64 81 104 113 92
49 64 78 87 103 121 120 101
72 92 95 98 112 100 103 99
14 = 14; Encode 0
20 < 22; Encode 1
Fig.10.MBEC encoding

14. Metrics for quality:
 Peak Signal to Noise Ratio(PSNR) PSNR> 0.35 dB
PSNR = 10 log10 . A2
1
N x M [f(i,j) – f’(i,j)]2
 Normalized Cross-correlation(NC) NC>0.75
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WatermarkingTechniques

15. LSB & DCT : Comparison
LSB Substitution
technique
DCT technique
Spatial domain technique Frequency domain technique
Provides limited ROBUSTNESS Provides better ROBUSTNESS
Embeds little INFORMATION Embeds more INFORMATION
Lesser NOISE immunity Highly immune to NOISE
SIMPLE implementation COMPLEX implementation
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Digital Image Protection UsingAdaptive
WatermarkingTechniques
Table.1.LSB and DCT technique comparison

16. Conclusion
 DigitalWatermarking proves crucial.
 A combination of more than one technique is
required.
 DCT proves to be advantageous.
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Digital Image Protection UsingAdaptive
WatermarkingTechniques

17. References
[1].Yusuf Perwej, Firoj Parwej ,Asif Perwej -The International
Journal of Multimedia & Its Applications (IJMA)Vol.4, No.2,
April 2012,An AdaptiveWatermarkingTechnique for the
copyright of digital images and Digital Image Protection.
[2] Lin Liu -A Survey of DigitalWatermarkingTechnologies.
[3]. Petitcolas, F.A. P.,Anderson, R. J.: Kuhn, M. G.,
Information Hiding –A Survey, Proceedings of the IEEE,
Special Issue on Protection of Multimedia Content.
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Digital Image Protection UsingAdaptive
WatermarkingTechniques

18. THANKYOU…!
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WatermarkingTechniques

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WatermarkingTechniques