Slajd 1

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Information hiding in stationary images
staff corporal Piotr Lenarczyk Military
Uniwersity of Technology Institute of
Electronics and Telecomunication
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Watermarking

• Digital image watermarking means embedding
  information into image in such a way that it is
  imperceptible to a human observer, but can be
  easily detected by special computer algorithm.
• Ingemar J. Cox

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Applications of watermarking

• Owner Identification
• Proof of Ownership
• Copy Control
• Device Control
• Broadcast Monitoring
• Content Authentication

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Method of changing Discrete Cosine Transform
coefficients in frueqency domain
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2-Dimensional Discrete Cosine Transform DCT 2D
M,N 8 m,n discrete index of pixel
position k,l discrete index of DCT coefficient
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DCT 2D Basis Functions
Q
Basis functions matrices of Discrete Cosine
Transform for block 8x8 pix
2 dimensional Discrete Cosine Transform
coefficients
Standard quantization matrix used in JPEG
algorithm
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A
Matrix A represents block of 8 x 8 pixel values
Original image
0,55
23,55
B
Matrix B represents DCT 2D calculated on matrix
A
Watermarked image
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Perceptual transparency
Data payload
Robustness
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Original picture
Watermarked picture for scalling coefficient k23
Watermarked picture for scalling coefficient
k3000
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BCH code influence on Bit Error Rate
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• Thank you for your attention.
• Questions?