Combinational image watermarking in the spatial and frequency domains

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Combinational image watermarking in the spatial
and frequency domains

• Source Pattern Recognition, Vol. 36, No. 4,
  April
• 2003, pp. 969-975
• Authors Frank Y. Shih, Scott Y.T. Wu
• Speaker Yu-An Ho
• Date 2004/2/6

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Outline

• Introduction
• Flowchart
• The watermarking in the spatial domain
• The watermarking in the frequency domain
• Experimental results
• Random sequence generator
• Conclusions
• Comments

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Introduction

• There are many aspects to be noticed in
• Watermarking design
• Imperceptibility
• Security
• Robustness
• Capacity

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Flowchart
DCT

IDCT

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The watermarking in the spatial domain
LSBleast significant bits

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The watermarking in the frequency domain (1/2)
88 block
22 Watermark block
Host Image 256256 Total blocks 3232
Watermark 6464 Total blocks 3232
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The watermarking in the frequency domain (2/2)

22 Watermark block
88 block
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Experimental results (1/4)
A 6464 image is cut from a 128128 image.
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Experimental results (2/4)
A 6464 image is cut from a 256256 image.
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Experimental results (3/4)
The extracted watermark.
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Experimental results (4/4)
Table 1. The comparisons when embedding different
sized watermarks into a Lena image with size
256256.
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A 12-bit random sequence generator
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Flowchart
DCT


IDCT
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Experimental results
Cropping half of a Lena image.
Table 2. Cutting different sizes
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Conclusions

• The capacity is increased.
• The degree of protection is double.

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Comments

• Watermark of Gray image.
• Design random sequence generator.