Adaptive Data Hiding in Palette images by Color Ordering and Mapping With Security Protection

1
Adaptive Data Hiding in Palette images by Color
Ordering and Mapping With Security Protection

• Authors Chih-Hsuan Tzeng, Zhi-Fang Yang, and
  Wen-Hsiang Tsai
• Source IEEE Transactions On Communications, Vol.
  52, No. 5,
• May 2004, pp. 791-800.
• Impact Factor 1.455 (Rank 44/20921)
• Speaker Yu-An Ho(???)
• Date 2006/01/13

2
Abstract

• Palette images are widely used in multimedia and
  Internet applications.
• In this paper, a new method for data hiding in
  palette images with security protection by color
  ordering and mapping, as well as parameter
  randomization, is proposed.
• The experimental results show that secret data
  can be embedded and extracted successfully
  without producing visual artifacts in the cover
  image.

3
Outline

• Introduction
• The proposed method
• Color-ordering relationship
• Color-mapping function
• Data-embedding process
• Data-extraction process
• Experimental results
• Conclusions

4
Introduction (1/2)

• Gifshuffle
• The idea is to permute the colors in the palette
  of an image in a specific order in accordance
  with the secret data. (256!)

Ex 4!
5
Introduction (2/2)
(b) Replacement by the closet color.
(c) Replacement by the neighboring color.
(a) The original image.
Three colors c1, c2, c3, with RGB values (0, 174,
239), (57, 181, 74), and (236, 0, 140) are
contained in the sample images.
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Color-ordering relationship
7
Proposed data-embedding process (1/3)
How to compute values?
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Proposed data-embedding process (2/3)
Non-embeddable
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Proposed data-embedding process (3/3)
embeddable
10
Color-mapping function (1/2)
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Color-mapping function (2/2)
Hiding 0
Hiding 1
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Data-extraction process
13
Experimental results (1/3)
15640 bits/44.8dB
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Experimental results (2/3)
2003 bits/43.7dB
15
Experimental results (3/3)
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Conclusions

• The experimental results show that secret data
  can be embedded and extracted successfully
  without producing visual artifacts in the cover
  image.
• A good balance between stego-image quality and
  data-embedding capacity can be achieved.

17
Questions (1/2)

• Which one is palette image?
• (a) GIF, (b) JPEG, (c) BMP, (d) MPEG.
• What is the most important for data hiding?
• (a) Capacity, (b) Robustness, (c) Invisibility
  (d) above.

18
Questions (2/2)
Which one is wrong of following ?
(a)
(b)
(c)
(d)