【正文】 graphFormatLineSpacingLinesToPointselectionParagraphFccccccccccccccccccccccccccccccccccccccccccccccccccccccccormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraSelec SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesTSelectionParbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbagraphFoLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointse11111111111111111111111111111111lectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraphFormatLineSpaci2222222222222222222222ngLinesToPoints2SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraphFccccccccccccccccccccccccccccccccccccccccccccccccccccccccormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraSelec 設(shè) X(m， n)是一幅大小為 M*N灰度級(jí)為 2“的灰度圖像 (1≤ m≤ M ，1≤ n≤ N)，其中 M， N， a為正整數(shù)。考慮到量化低 頻子圖可能產(chǎn)生較大失真，因此不在其中嵌入水印，而選擇除低頻外的中頻系數(shù) [3]。把 XK， l (mi， nj)分成一定大小的塊，用 Block (s， t)表示 XK， l (mi， nj)中大小為 s t的系數(shù)塊，其 中 s=1，2，…， mi ， t=1， 2，…， nj， b為正整數(shù)，代表該塊的編號(hào)。 量 化 水印序列 w的嵌入是通過(guò)對(duì) Ave 的量化完成的，例如：量化成奇數(shù)代表嵌入“ 1”，量化成偶數(shù)相當(dāng)于嵌入“ 0”。用 Dat(i， j)表示 Block 中的一個(gè)小波系數(shù)，量化后的該系數(shù)用 Dat ′ (i， j)表示，其中 i=1， 2，…， s； j=1， 2，…， t。 若 Turdat與 wi相同，則量化的小波系數(shù)為 Dat′ (i， j)=Dat(i， j)+[T]△ l Ave 若 Turdat與 wi不同，小波系數(shù)按下列量化 Dat′ (i， j)=Dat(i， j)+（ [T]+1）△ l– Ave， T≥ [T] Dat′ (i， j)=Dat(i， j)+（ [T]1）△ l – Ave， T[T] 使用相同的小波基，通過(guò)小波逆變換生成含有水印的圖像，并將小波基、小波分解層數(shù)、選擇的系數(shù)區(qū)域、分塊方法、量化間隔、奇偶對(duì)應(yīng)關(guān)系記錄形成密鑰 [4]。首先對(duì)要檢測(cè)的圖像進(jìn)行小波變換，根據(jù)密鑰確定嵌入水印的位置，并對(duì)水印進(jìn)行置亂處理的逆運(yùn)算。歸一化互相關(guān)函數(shù) Nc的定義式為 SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesTSelectionParbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbagraphFoLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointse11111111111111111111111111111111lectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraphFormatLineSpaci2222222222222222222222ngLinesToPoints2SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraphFccccccccccccccccccccccccccccccccccccccccccccccccccccccccormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraSelec SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesTSelectionParbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbagraphFoLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointse11111111111111111111111111111111lectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraphFormatLineSpaci2222222222222222222222ngLinesToPoints2SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraphFccccccccccccccccccccccccccccccccccccccccccccccccccccccccormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraSelec 峰值信噪比 Rpsnr 的定義式為 上兩式中， Wij為原始水印， Wij‘ 為提取出來(lái)的數(shù)字水印， i， j分別是行和列的個(gè)數(shù)。當(dāng)對(duì)原圖和含水印圖進(jìn)行 JPEG壓縮后，原圖峰值信噪比為 33． 70dB，含水印圖峰值信噪比為 31． 95dB。 從實(shí)驗(yàn)數(shù)據(jù)中可以看出，本文提出的算法對(duì) JEPG壓縮、剪切、中值濾波具有較強(qiáng)的魯棒性。 SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesTSelectionParbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbagraphFoLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointse11111111111111111111111111111111lectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraphFormatLineSpaci2222222222222222222222ngLinesToPoints2SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraphFccccccccccccccccccccccccccccccccccccccccccccccccccccccccormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraSelec SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesTSelectionParbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbagraphFoLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointse11111111111111111111111111111111lectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraphFormatLineSpaci2222222222222222222222ngLinesToPoints2SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraphFccccccccccccccccccccccccccccccccccccccccccccccccccccccccormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraSelec SelectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointselectionParagraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesTSelectionParbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbagraphFoLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPointse11111111111111111111111111111111lectionParagraphFormatLineSpacingLinesToPointsSelectionParagraphFormatLineSpacingLinesToPoctionParagraphFormatLineSpaci2222222222222222222222ngLinesToPoints2SelectionParagraphFormatLineSpaci