新一代的JPEG2000影像壓縮格式能支援影像中重要的興趣範圍(Region of Interest)區域以較高的位元編碼，是將浮水印藏入於有興趣範圍區域以保護有興趣範圍之影像有甚多之研究，但一般所嵌入浮水印於有興趣範圍之影像之浮水印受到幾何攻擊(Geometric Attack)時，若所需偵測之浮水印在嵌入時與擷取時之空間座標無法同步(Synchronization)，即會導致浮水印擷取上之困難。為了解決此一問題，採用具同步機制之浮水印法是一個有效的方法。
　　網格架構(Grid Structure)之浮水印技術是在影像空間域中嵌入網格樣本(Grid Pattern)，以產生同步之能力來對抗旋轉、縮放等幾何及影像處理上之攻擊。本論文基於網格架構空間域同步之原理提出一混合式網格嵌入架構於JPEG2000有興趣範圍浮水印之偵測上，此混合式網格架構兼具空間同步定位之能力，因此在偵測上採用及自相關(Autocorrelation)與交相關(Cross correlation)之運算，即能對抗旋轉，縮放剪裁等幾何及一般影像處理上之攻擊，更由於具定位能力之關係，因此是對於受到剪裁攻擊之影像則不需耗費大量位移之運算，就能準確找出被剪裁影像在原影像的位置，進而擷取藏在有興趣範圍內之浮水印。
　　對於已嵌入此種可同步定位之混合式網格架構及認証浮水印之影像Lena，實驗証明其有興趣範圍部份之影像經過剪裁等幾何攻擊可利用交相關演算法即可快速檢測其在原圖之原始位置。此浮水印嵌入法在考慮其強健性下，其影像品質可達38.711db，而對一般的影像處理上及幾何之攻擊其正規化關聯值(Normal Correlation)大部份皆在門檻值0.725以上。

　　JPEG2000, a new standard for the compression of still images, supports Region of Interest (ROI) that could encode important areas in an image with higher fidelity. some researches focus on embedding Watermark in region of interest, but the loss of synchronization caused by geometrical attack to an image will increase the difficulty of watermark detection.
　　In this paper, we propose Synchronization Detection of JPEG2000 ROI Watermark with Hybrid Grid Structure. Through the following process, the concealed ROI watermark could be extracted: Add grid positioning system to the image’s spatial domain. Next, conceal the watermark into JPEG2000 ROI against cropping and gyration attack. Put the cropping attacked image and proposed grid positioning system to correlation algorithm method, which could find out precisely the original location of the cropped image without massive displacement operation.

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