Image steganographic scheme based on pixel-value differencing and LSB replacement methods Author: Wu, H.-C., Wu, N.-I., Tsai, C.-S. and Hwang, M.-S. Source: IEE Proceedings on Vision, Image and Signal Processing, Vol. 152, No. 5, October 2005, pp. 611-615. Speaker: Kai-Jung Shih Date: 2005.11.24 Wu, H.-C.：中技資管吳憲珠老師 Wu, N.-I.：朝陽通訊所吳男益同學 Tsai, C.-S.：中興資管蔡垂雄老師 Hwang, M.-S.：中興資管黃明祥老師
Review: Pixel-value Differencing Wu, D.C., and Tsai, W.H.: “A steganographic method for images by pixel-value differencing”, Pattern Recognition Letter, 2003, 24, (9-10), pp. 1613–1626 p1 p2 p3 p4 pi pi+1 … 100 162 140 255 Da-Chun Wu：高雄第一科大資管所吳大鈞老師 Wen-Hsiang Tsai：交大資工蔡文祥老師 d1= 62 d3= 0 di= 255 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory
Review: Range Table Ranges li ui wi R1[0, 9] 9 10 3 R2[10, 16] 16 7 9 10 3 R2[10, 16] 16 7 2 R3[17, 31] 17 31 15 R4[32, 63] 32 63 5 R5[64, 164] 64 164 101 6 R6[165, 255] 165 255 91 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory
Review: Hiding Process Secrete data b p1 p2 Range li ui wi R4[32, 63] 32 63 5 100 162 =00101(2) =5(10) d1= 62 p1 p2 100 162 p1’ p2’ 113 140 113 140 d1’ = li+b = 32+5 = 37 m=|d1’-d1| = |37-62| = 25 13 12 d1’= 37 32 62 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory
Proposed: Level Division Ranges Division li ui wi R1[0, 9] lower-level 9 10 3 R2[10, 16] 16 7 2 R3[17, 31] higher-level 17 31 15 R4[32, 63] 32 63 5 R5[64, 164] 64 164 101 6 R6[165, 255] 165 255 91 Div = 16 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory
Hiding Lower-level in LSB 6 bits secrete =1 1 1 0 0 0(2) p1 p2 Range Division li ui wi R2[10, 16] lower-level 10 16 7 2 30 15 d1= 15 p1= 00011110(2) p2= 00001111(2) p1’ p2’ 00011111(2) 00001000(2) 23 16 p2 8 p1 31 23 16 d1’=|31-8|=23 > Div=15 d1’= 7 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory
Experimental Result 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory
Experimental Result II 多媒體暨網路安全實驗室 Multimedia and Secure Networking Laboratory