a hierarchical digital watermarking method for image tamper detection and recovery n.
Download
Skip this Video
Download Presentation
A Hierarchical Digital Watermarking Method for Image Tamper Detection and Recovery

Loading in 2 Seconds...

play fullscreen
1 / 19

A Hierarchical Digital Watermarking Method for Image Tamper Detection and Recovery - PowerPoint PPT Presentation


  • 117 Views
  • Uploaded on

A Hierarchical Digital Watermarking Method for Image Tamper Detection and Recovery. Phen-Lan Lin, Chung-Kai Hsieh, and Po-Whei Huang Pattern Recognition Vol. 38, Issue 11, December 2005, pp. 2519-2529. Outline. Introduction The Proposed Method Watermark Embedding

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'A Hierarchical Digital Watermarking Method for Image Tamper Detection and Recovery' - hector-garza


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
a hierarchical digital watermarking method for image tamper detection and recovery

A Hierarchical Digital Watermarking Method for Image Tamper Detection and Recovery

Phen-Lan Lin, Chung-Kai Hsieh, and Po-Whei Huang

Pattern Recognition

Vol. 38, Issue 11, December 2005, pp. 2519-2529

outline
Outline
  • Introduction
  • The Proposed Method
    • Watermark Embedding
    • Hierarchical Tamper Detection
    • Tampered Image Recovery
  • Experimental Results
  • Conclusions
  • Comments
introduction
Introduction
  • Watermarking Method for Image Tamper Detection and Recovery
block mapping sequence generation algorithm 4 4 pixels block
Block mapping sequence generation algorithm (4 ×4 pixels/block)
  • 1-1 mapping : X ' = [ f ( X ) = ( k × X ) mod N ] + 1,
  • X , X ' are the block number (∈ [0, N− 1 ])
  • k is a secret key, (a prime and ∈ Z − {N 's factors })
  • N is the total number of blocks in the image

The original block

The mapping of blocks

X '=13×X mod 64 +1

watermark embedding 1 2

r

Watermark Embedding (1/2)

avg_As=(I1+I2+I3+I4)/4

avg_Bs=(I1+I2+I3+I4)/4

Block A

avg_B=(I1+I2+…+I16)/16

Block B

watermark embedding 2 2
Watermark Embedding (2/2)

Block A

num: # of 1s in the 6 MSBs of avg_Bs

avg_As=(69+78+35+46)/4=57=(00111001)2

r = 001110

Block B

avg_Bs=(104+20+36+52)/4=53=(00110101)2

avg_B=(104+20+96+204+…+164)/16=97

v=0, p=1

104

104

Set 2LSBs to 0

22

22

39

39

55

54

hierarchical tamper detection 1 3
Hierarchical Tamper Detection (1/3)

Level 1: for each sub-block B's of 2×2 pixels within block B' , verify v and p

avg_B’s=(104+20+36+52)/4=53=00110101

avg_B’=(104+20+96+204+…+164)/16=97

v'=0, p'=1

ifv'is not equal to v

OR if p'is not equal to p

 This sub-Block is marked erroneous

v=0, p=1

After Level 1 detection, each sub-block is marked valid of erroneous

hierarchical tamper detection 2 3
Hierarchical Tamper Detection (2/3)

Level 2: For each block of size 4 × 4 pixels, mark this block erroneous if any of its sub-block is marked erroneous; otherwise, mark it valid.

After Level 2 detection, each block is marked valid of erroneous

Level 3: For each valid block of size 4×4 pixels, mark the block erroneous if there are five or more erroneous blocks in its 3×3 block-neighborhood,

Most surrounding blocks of some valid block are erroneous,

this block hardly remains valid.

hierarchical tamper detection 3 3
Hierarchical Tamper Detection (3/3)

Level 4: only required for resisting against VQ attack,

assume mapping sequence:B C

valid

Block C

r = 001110(00) = 56 = avg_Cs

avg_B’s=(68+76+32+44)/4=55

valid

57=00111001=00111000=56

avg_B’s avg_Cs

Block B’

tampered image recovery
Tampered Image Recovery

Mapping sequence: A B

valid

Block B

r = 001110(00) = 56

erroneous

Tamped Block A

Recovered Block A

experimental results 3 7
Experimental Results (3/7)
  • M1: Covering the whole image with leaf patterns, as depicted in Fig. 8(b).
  • M2: Covering the whole image with another image, as depicted in Fig. 8(c).
  • M3: Covering the whole image with fruit patterns, as depicted in Fig. 8(d).
  • M4: Spreading plenty of mist to the whole image, as depicted in Fig. 8(e).
conclusions
Conclusions
  • A hierarchical digital watermarking scheme for image tamper detection and restoration is proposed.
  • The proposed method uses parity check and intensity comparison with 3-Level detection for tamper detection.
  • The proposed method uses 2-LSBs of each pixel to restore the check bits and restore information.
comments
Comments
  • Level 4 detection resists against VQ attack (collage attack)
  • Something is wrong withLevel 4 detection
  • Reversible watermarking such as DE or histogram shifting is not suitable for tamper detection and recovery, this is because the bit-rate is low.