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Inverted Pattern Approach to Improve Image Quality of Information Hiding by LSB Substitution. Source: Pattern Recognition , In Press, Accepted Manuscript, Available online 9 February 2008 Authors: Cheng-Hsing Yang Speaker: Pei-Yan Pai Date: 2008.3.11. Introduction (1/2).
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Inverted Pattern Approach to Improve Image Quality of Information Hiding by LSB Substitution Source: Pattern Recognition, In Press, Accepted Manuscript, Available online 9 February 2008Authors: Cheng-Hsing Yang Speaker: Pei-Yan Pai Date: 2008.3.11
Introduction (1/2) • Simple LSB substitution (181) Data string: 00101011101100011101010011… (178)
Introduction (2/2) • Optimal pixel adjustment process (OPAP) K bits A pixel H: MSB LSB i.e., A K-bit string S, H =10110101(181) ,H’=10111110(190), k=4 => LSB=0101(5), S =1110(14) , then If LSB – S > LSB – S =5-14= -9 is greater than Else If LSB – S > So,
Proposed scheme (1/2) • Inverted pattern approach (inverted of S) Split the embeded bit string to P parts, P=pattern length i.e., P=1 P=2 P=4 P=8
Proposed scheme (2/2) We could use 1 bits per block to represent inverted or not inverted. • Inverted pattern approach i.e. (1= inverted, 0 = not inverted) Original string: Modified string: Inverted pattern: 0 1 1 0 1 0 0 0 The embedding rules: The embedded string is S, and the replaced string is RFor P part in i =1 to P If MSE(Si,Ri) MSE(i,Ri) i.e. s=111 =000 P: 10010101(149) Ps: 10010111(151) P : 10010000 (144)MSEPs = 4 MSEP = 25 So, choose s for embedding. Choosed Si for embeded If MSE(Si,Ri) MSE(i,Ri) Choosed ifor embeded End
The experiment results (2/4) cover image The results of embedding 512 × 256 secret images into cover image Lena by different LSB substitution approaches: OPAP LSBandIP LSB with different pattern lengths.
The experiment results (3/4) cover image The results of embedding 512 × 256 secret images into cover image Baboon by different LSB substitution approaches: OPAP LSBandIP LSB with different pattern lengths.
The experiment results (4/4) The MSE values of embedding 512 × 256 secret images into512 × 512 cover images by different approach.
Conclusions • Short computation time • High capacity • Better quality than previous methods