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IMAGE ADAPTIVE FRAGILE WATERMARKING

2. What is Watermarking?. Digital watermarking is a technique for inserting information (the watermark) into an image, which can be later extracted or detected for variety of purposes including identification and authentication purposes. . 3. A watermark may be:. Fragile: distorted or broken under

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IMAGE ADAPTIVE FRAGILE WATERMARKING

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    1. 1 IMAGE ADAPTIVE & FRAGILE WATERMARKING EDA ORMANCI EBRU ARISOY

    2. 2 What is Watermarking? Digital watermarking is a technique for inserting information (the watermark) into an image, which can be later extracted or detected for variety of purposes including identification and authentication purposes.

    3. 3 A watermark may be: Fragile: distorted or broken under slight changes Semi-fragile: designed to break under all changes that exceed a user- specified threshold Robust: withstand moderate to severe signal processing attacks (compression, rescaling,filtering)

    4. 4 The requirements for image adaptive watermarking schemes are

    5. 5 The image adaptive watermarking procedure

    6. 6 Watermark is inserted to the DCT coeffients of the each block of the image by using the technique below: Yk (u,v) = Xk(u,v)+Jk(u,v)Wk (u,v) |Xk (u,v)| > Jk(u,v) Xk (u,v) elsewhere

    7. 7 How can we determine the Treshold J(u,v) in watermark embedding? VISUAL MODELS

    8. 8 tij = qij/2 (Frequency sensitivity.) tijk = tij(C00k/C00)a (Luminance sensitivity.) mijk = Max[ tijk, |Cijk|w tijk1-w] (Contrast masking) eijk = Cijk - Round[Cijk/qij] qij Combination of all JNDijk = eijk / mijk (Just Noticable Distortion)

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    12. 12 Fragile Image Watermarks:

    13. 13 Secret Key Authentication/Verification Watermark

    14. 14 Secret Key Authentication/Verification Watermark

    15. 15 Public Key Authentication/Verification Watermark

    16. 16 Public Key Authentication/Verification Watermark

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