Thủy ấn dạng hiện sử dụng phép biến đổi DFT (Có Source Code)

Thuỷ ấn (Watermarking) được định nghĩa là kỹ thuật nhúng thông tin vào trong ảnh môi trường để xác định quyền sở hữu ảnh môi trường, chống sự giả mạo và xuyên tạc thông tin. Kích thước thông tin nhúng thường là nhỏ (từ vài bit tới vài nghìn bit). Kỹ thuật này cho phép đảm bảo nguyên vẹn thông tin được nhúng khi ảnh môi trường bị biến đổi bởi các phép thao tác như lọc (filtering), nén mất dữ liệu (lossy compression), hay các biến đổi hình học…

MỤC LỤC  1 TÓM TẮT   !" #$%&'!()*+!,&-'. '/'."0'.1 &1.2341'. 45'6788.8*9&":.;< 4-=.>44?&+1$  +34.34 ?&4 &'."0;@&A1; (B.3 CDCEF 4'6' '/6"0;@&A EG&HIJ 34?&A;'64 * * &"03H A1C%A3&H(;&.=( *KL0" I. GIỚI THIỆU 0&M;BNCEF'6OP EG&H .4'/%O?&Q@&4'/1 4.%&*"R'! '/ SB-.3!.A3F"RG&HI4 34&*.T'6E4'/3O3+U3Q I' VBW CF1I;(@ &B CF1 3+UAV5 0;(B.3 CDCEFA'6 .Q(@&ABA;'6F"#X;(1 .EA;'61'$'6 '6." :Y'6&;(, • 0;>Z4.!44& [4" • 0;>4O*.\ !2Y E3O%$Y];" • ^A;/A;1'_E 4'Q+ 4'/14" • ` 3S;4E$E2.EIa.3S& A434?&" 2 • 0;4'61$ '/.?&A" II. PHÁT BIỂU BÀI TOÁN 1. Phát biểu bài toán b;, c>&.,def4,g4'/h1g49 ijf4$\E'!" c>&,k9(hl" 2. Hướng giải quyết #$f'!+H4?&+3;, ^'!9;(*E419 +E4 &./+*O/ 4V *3+ H*"&$1A 34?&.437UO 4E4'Q&+; '64.434 3.@'!@;$$.! 394<&M.="cA+H 'a 3?&V;BmbnmCWbF5 ^'!9 o(8'aE4+E ?&EG&H3+U"#EG&H3+U .8 &3+ HE1'.H&. /'63&()!.!3+!" &$1A&M.=.437U 3+U@6434; '64. 3.@&M.=&E"#$&I3+U(@ & 4$$'a3+U'6o(8;'K#0 BKCC  #C  0pF1  KL0  BKCC  L&C  0pF1  KN0 KCCN.C C0pBF5 031C*9&.+HEG&H;C'! 9f1;*>4?&3+ UKL0" RG&H&M;o(8I3+UKL04 E1I3+UKL0.!-E4'6 3 >;1@.>"cEG&H&M;3.@ V>@qE3&M;C KL04E+?&4C9&, BgF 0$, n,, , > '6 E4E+?&414'/14 >KL0" n : 3+UKL0'a9E4Brg1f1s15F #.'6!E4'a9,."`!  OS;. !;Q. OS ;. !;" III. THUẬT TOÁN 1. Phép biến đổi DFT tI3+UKL0f&H;:%u,       +− − = − = ∑ ∑ = N yv M xu j M x N y eyxfvuF π 2 1 0 1 0 ),(),( (2) 0$,v≤&≤:ng1v≤.≤ung1wr 1− " 0$,C w% r%xw%"&BfF'a'a.!, ∑∑ − = − =       +−+= 1 0 1 0 )(π2sin)(π2cos),(),( M x N y N vy M ux j N vy M ux yxfvuF BsF nLB&1.F 9, xt>'a9.! xt>4'a9.!" tI3+UKL0'6, 4       + − = − = ∑ ∑ = N yv M xu j M u N v evuF MN yxf π 2 1 0 1 0 ),( 1 ),( (4) 0$,v≤%≤:ng1v≤≤ung R:ru, 0ABfFQ,       + − − = − = ∑ ∑ = N vyxu j N x N y eyxfvuF π 2 1 0 1 0 ),(),( v≤&≤ung1v≤.≤ungBflF 0AByFQ,       + − = − = ∑ ∑ = N yvux j M u N v evuF N yxf π 2 1 0 1 0 2 ),( 1 ),( v≤%≤ung1v≤≤ungBylF 2. 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