本論文提出一個以小波轉換為基礎，輔以改良對比度之可逆浮水印技術。此嵌入技術可將浮水印影像嵌入至數位影像中，而僅需使用嵌入浮水印後的掩護影像及嵌入過程所產生的例外紀錄，即可還原獲得原數位影像，並獲得已嵌入的浮水印影像。
本論文之嵌入浮水印演算法步驟如下。首先將欲嵌入浮水印之影像以鄰近的四個像素為一組分割成四張相似的影像。接下來對分割後的影像分別使用小波轉換處理。然後將用小波轉換處理過後的影像取LL的區塊使用本論文所提之改良式對比強化浮水印嵌入技術嵌入浮水印。之後使用反小波轉換將嵌入浮水印後的小波影像轉換回影像。最後只要將轉換回來的影像合併，即可得到嵌入浮水印的影像。
安全性方面，本論文將原影像分割成四張相似的影像，取其中一張作為浮水印嵌入的參考，選取另外三張嵌入浮水印，提高了沒有本論文的方法時欲還原成原本影像的困難度，與其他論文比相對來說更加安全。

A visible reversible image watermarking scheme embeds visible watermark into digital images for ownership identification and the embedded watermark can be removed to recover the original image. The proposed scheme first partitions the cover image to four similar images with half size in width and height. These 4 images are classified to two sets, fixed set (FS) and watermarked set (WS), and each image is then applied to forward wavelet transform for acquiring 4 low-pass subimages for embedding watermark image. The number of FS and WS deter-mines the stability or visibility of embedded watermarks. The coefficients in FS are stationary and the watermark image is embedded into low-pass coefficients of WS based on low-pass coefficients of FS. Experimental results show that the proposed scheme has good watermark similarity and good extraction result under cropped or noise attacks.

目錄
目錄	iii
圖目錄	v
表目錄	vi
第一章 緒論	1
1.1研究背景與動機	1
1.2浮水印相關研究	3
1.2.1可逆可見浮水印研究	4
1.3論文架構	5
第二章 相關研究	7
2.1小波轉換技術	7
2.2Lin [8]的方法	8
第三章 本論文提出方法	12
3.1嵌入流程	12
3.2影像還原與浮水印抽取流程	14
第四章 實驗結果及比較	16
4.1浮水印嵌入實驗	16
4.2與Lin[8]的方法作比較	20
4.3裁切影像還原實驗	22
4.4雜訊攻擊實驗	24
第五章 結論	28
參考文獻	29
附錄-研討會論文 31

圖目錄
圖1.1 Lena及小波轉換後的圖	8
圖4.1為本文用來嵌入掩護影像之黑白浮水印資訊	17
圖4.2以本文方法嵌入浮水印與還原後之結果比較圖	17
圖4.3以本文方法嵌入浮水印至不同掩護影像之結果比較圖	18
圖4.4分別以本文方法與Lin的方法嵌入浮水印之結果比較圖	21
圖4.5將以本文方法嵌入浮水印的兩張影像裁切後還原結果比較	23
圖4.6將掩護影像加入胡椒鹽雜訊後還原並抽取浮水印資訊的實驗結果	25
圖4.7將掩護影像加入高斯雜訊後還原並抽取浮水印資訊的實驗結果	27

表目錄
表4.1不同影像嵌入浮水印之溢位像素數及還原後之PSNR比較	19
表4.2不同裁切區塊與原圖wu值的比較	22

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