本論文針對JPEG壓縮攻擊提出靜態影像之浮水印方法。JPEG壓縮是相當普遍的影像儲存格式，同時對於數位浮水印也被視為一種攻擊。為了能從壓縮過的影像中正確的取出浮水印，我們利用JPEG壓縮量化表的特性，來避免量化過程中對浮水印資訊的破壞。
    為了強健性的考量，我們選擇頻率域內中頻靠近低頻的係數來藏入浮水印。同時為了增進系統的透明性，我們對影像進行斜線邊緣偵測，並統計邊緣點數，再將浮水印嵌入在影像中具有較多斜線紋理的區域中。
    由於MPEG動態影像壓縮中使用了類似JPEG的方法來壓縮畫格，因此我們也將浮水印方法延伸至動態影像。

JPEG compression is a common image store format and also an attack to watermarking techniques. In this paper, we propose a watermarking scheme to against the JPEG compression and this scheme provide good capacity and imperceptibility as well. By using the property of JPEG quantization table, we choose two pairs of DCT coefficients in each 8 × 8 blocks of the host image for embedding the watermark information. The blocks for embedding are chosen based on the edge point number of ±45º lines. 
We also extend our scheme to the video watermarking. The experimental results show our method is robust against many kinds of general attacks, especially JPEG and MPEG compression, and the performance of imperceptibility is equally well.

目錄
第一章 緒論		1
1.1 	研究動機與目的		1
1.2	研究內容		2
1.3	論文架構		4
第二章 相關研究與理論基礎	 5
2.1	浮水印技術相關知識		5
2.2	浮水印技術相關研究		10
2.3	JPEG影像壓縮概述		13
第三章 研究方法	15
3.1   嵌入浮水印	16
3.1.1 斜線紋理區塊	22
3.1.2  高亮度區塊	24
3.1.3  嵌入步驟	25
3.2   擷取浮水印	29
第四章 實驗結果與探討	30
第五章 結論與未來研究方向	45
參考文獻	46
英文論文	47
圖目錄
圖1.1 	系統流程圖 (a)浮水印藏入流程圖 (b) 浮水印取出流程圖		3
圖2.1	多階離散小波轉換示意圖		8
圖2.2	Sobel邊緣偵測遮罩		9
圖3.1	JPEG標準量化表		16
圖3.2	嵌入位置示意圖		17
圖3.3	二元浮水印		21
圖3.4  彩色載體影像Lena	21
圖3.5  Sobel正負45度邊緣偵測之遮罩	22
圖3.6  正負45度斜線之邊緣偵測結果	23
圖3.7  斜線紋理區塊	23
圖3.8  高亮度區塊	24
圖4.1  二元浮水印	30
圖4.2  彩色載體影像 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	31
圖4.2  彩色載體影像 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	31
圖4.3  斜向邊緣偵測結果 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	33
圖4.4  斜向紋理之嵌入區塊 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	34
圖4.5  斜向紋理嵌入結果 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	35
圖4.6  高亮度嵌入區塊 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	36
圖4.7  高亮度區塊嵌入結果 (a)Lena (b)Airplane (c)Baboon (d) Sailboat 	37
圖4.8  灰階載體影像	40
圖4.9  MPEG影像格式	42








表目錄
表4.1 	浮水印透明性實驗結果		39
表4.2	浮水印對JPEG壓縮之強健性實驗結果		41
表4.3	浮水印對一般攻擊之強健性實驗結果		42
表4.4	動態影像浮水印方法之實驗結果		44

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