浮水印技術為嵌入資訊於數位影像中之一種技術，再藉由資料抽取的步驟，取出原嵌入的資訊。而可逆浮水印技術(Reversible Image Watermarking)在抽取已嵌入的浮水印資訊後，可以同時獲得完整的原始影像。可逆浮水印技術對於著作權的保護，有很重要的保護功能。
至目前有眾多可逆浮水印的技術被提出。近年來，有學者提出類別索引表(Class Index Table, CIT)方法，藉由區塊內排列順序的調整，建立視覺上與掩護影像相似的浮水印嵌入後的圖。然而，直接使用類別索引表的浮水印嵌入後之視覺效果並不好，本論文研究使用彩色影像間之配對方式，透過影像區塊距離矩陣、貪婪式配對方式及類別索引表嵌入三大步驟，進行快速的計算處理，以期能獲得高效能及高品質之掩護影像。本論文比較多種類別索引表的方法，並期能獲得較佳的參數組合。

A reversible image watermarking scheme recovers the original image after extracting the embedded watermarks. A conventional CIT-based image watermarking method segments digital images to combination of non-overlapped blocks. Blocks of the original image is one-to-one mapped to blocks of the covered image for acquiring the watermarked image. The mapping table is needed for perfectly recovering the original image from the watermarked image. Quality of the watermarked image is determined by mapping procedure and the selection of mapping table. In this study, we examine different selection strategies to present an efficient method for acquiring good quality of the watermarked image. Analysis with other selected strategies, like random preprocessing or nearest matching, are compared. Moreover, color image has better watermarked image quality than gray-level image. For acquiring good watermarked image, nearest matching is the so-far best strategy on the CIT-based method. Experimental results show that the watermarked image has a similar visual effect to the target image but can perfect recover to the original image by using the mapping table.

目錄
 第一章 緒論	1
1.1	研究背景	1
1.2	研究動機	1
1.3	研究目的及問題	2
1.4	研究架構	3
 第二章 文獻探討	4
2.1	類別索引表技術介紹	4
2.2	二元關係(Binary Relations)	6
2.3	二分圖配對法(Bipartite Matching)	7
 第三章 本論文所提出之方法	9
3.1	直接配對法	10
3.2	亂數前處理法	11
3.3	貪婪式配對法	11
3.4	各種方法比較	15
 第四章 實驗結果與分析	19
4.1	實驗結果	19
4.2	比較分析	24
 第五章 結論	27
 參考文獻	28
 附錄-英文論文	31
 
圖目錄
圖一、影像區塊與對應之類別索引表	4
圖二、利用類別索引表的影像區塊浮水印計算	5
圖三、(2,4,3)類別索引表技術中，可能產生錯誤還原的情形	6
圖四、兩種f : AB的對應關係圖	7
圖五、本研究處理步驟圖	9
圖六、本研究結果示意圖	10
圖七、直接配對法的一對一配對方式	10
圖八、原始影像I與參考影像C的區塊編號定義	12
圖九、本研究所提出貪婪式配對法之浮水印嵌入演算法	14
圖十、本研究的配對方式與各種前處理的關係	16
圖十一、本研究所採用的影像	20
圖十二、原始影像為Airplane，參考影像為Baboon的實驗結果	21
圖十三、原始影像為House，參考影像為Pepper的實驗結果	22
圖十四、原始影像為Pepper，參考影像為House的實驗結果	24

表目錄
表一、四種方法的理論比較	17
表二、六種重要不同的亂數前處理、距離矩陣計算、與配對式方法	20
表三、四種方法的範例比較值	24
表四、不同影像與處理方法所需的執行時間	25

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