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Multilevel reversible data hiding based on histogram modification of difference images. Authors: Chia-Chen Lin, Wei-Liang Tai, and Chin-Chen Chang Source: Pattern Recognition, vol. 41, no. 12, pp. 3582-3591, 2008 Presenter: Chia-Chun Wu ( 吳佳駿 ) Date: 2009/09/04. Outline.
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Multilevel reversible data hiding based on histogram modification of difference images Authors:Chia-Chen Lin, Wei-Liang Tai, andChin-Chen Chang Source:Pattern Recognition, vol. 41, no. 12, pp. 3582-3591, 2008 Presenter: Chia-Chun Wu (吳佳駿) Date: 2009/09/04
Outline • Introduction • Requirements • Related work • "Reversible Data Hiding," Z. Ni, Y. Q. Shi, N. Ansari, and S. Wei, IEEE Transactions on Circuits and Systems for Video Technology, vol. 16, no. 3, pp. 354-362, 2006 • Proposed Scheme • Experimentation & Comparison • Conclusions
要解決的問題 • 此篇論文主要是利用一般影像比較平滑,相鄰兩個像素值非常相近(差值很小)的特性,因此差值介於-1 ~ +1之間的個數佔了大多數,此時,統計差值取絕對值後的數量,以差值最多的當成Peak bin,結合Ni等人提出來的直方圖無失真資料隱藏的方法,藉由調整相鄰兩個像素的差值,便可以達到高容量、低失真的無失真資料隱藏的目的。
Introduction • Data hiding • Reversible data hiding
Requirements • 1. Payload Size • 2. Image Quality • 3. Reversible
Peak bin Zero bin 86420 number • 23456 • pixel value {0} {1} Ni et al.’s scheme (1/2) • Embedding • Cover image • Cover image’ • Cover image’ • Stegoimage Secret { 1, 0, 0, 0, 1, 0, 1 }
Secret { 1, 0, 0, 0, 1, 0, 1 } Peak bin Zero bin 86420 number • 23456 • pixel value {0} {1} Ni et al.’s scheme (2/2) • Extracting & Recovering • Stegoimage • Cover image’ • Cover image’ • Cover image
A B Histogram Modification Histogram Modification C D Histogram Modification Histogram Modification Proposed Scheme (1/6) • Stegoimage • Cover image A A’ B’ B C C’ D’ D
86420 number 0 1 2 3 4 5 pixel value Proposed Scheme (2/6) • Create the histogram • Cover image • Absolute difference image • Differenceimage
{0} {1} Proposed Scheme (3/6) • Embedding • Absolute difference image Peak bin 86420 number • Absolute difference image’ 0 12345 pixel value Secret { 1, 0, 0, 0, 1, 0, 1 }
Proposed Scheme (4/6) • Stego image generating For the first two pixels in each row For any residual pixels • Difference image’ ? • Absolute difference image’ • Stegoimage • Cover image
86420 number 0 12345 pixel value {0} {1} Proposed Scheme (5/6) • Extracting & Recovering Peak bin • Stegoimage • Absolute difference image’ • Absolute difference image Secret { 1, 0, 0, 0, 1, 0, 1 }
Proposed Scheme (6/6) • Recoveringoriginalcover image • Absolute difference image • Stegoimage • Cover image
Conclusions • Proposed a reversible data hiding with large capacity • When the algorithm is performed for nine rounds, the average PSNR is still higher than 30 dB and the average hiding capacity still can reach 1.3 bpp.
此篇論文之優缺點 • 優點: • 跟Ni.等人的方法比起來,此方法不用額外記錄Zero bin的資訊。 • 本方法先將整張Cover Image切成四張獨立的Sub-Image,分別統計子影像中相鄰兩個像素值的差值,並利用每一張子影像的Peak bin來調整相鄰兩個像素值的差值,達到無失真資料隱藏的目的,因此隱藏量會比其它方法高。 • 缺點: • 跟Ni.等人的方法比起來,此方法需額外記錄更多Peak bin的資訊。