隨著科技不斷地發展，近年來在數位影像處理技術已提出了許多相關的新理論及新的演算法，人類也越來越重視數位影像的發展，為了滿足科技發展上的需求，影像處理技術就顯得相當重要。
最近幾年，網路的發展與數位科技的成長越來越快。然而，數位多媒體資訊在網際網路中很容易被竄改或破壞，所以智慧財產權的保護也相形的更為重要。就目前的發展來說，很多研究提出影像認證的方法，如強健型浮水印、易碎型浮水印、半易碎型浮水印以及竄改偵測與回復的技術。目前有的影像認證研究都只能取出數位浮水印或是偵測與回復被竄改的區域，而無法兼具兩者的功能。然而這些方法都沒有辦法對影像提供真正完整的保護。基於這個原因，我們提出一個新的思維：不只能夠把遭竄改的區域準確的偵測並回復它，並且藏入數位浮水印來當作認證用，還能夠抵抗一些基本的攻擊。
在這篇論文中，我們提出一個具有竄改偵測與回復功能之影像浮水印技術。主要的目標是能夠準確的偵測及回復被竄改的區域，除此之外，亦具有某種程度的強健型數位浮水印功能，能夠抵抗裁切攻擊。
影像中加入適當的浮水印技術，則可有效防止遭遇有心人士的竄改，保護影像的原始性及完整性，將可提供多功能的保全機制，特性如下四點：

a.無法察覺性：
最重要的條件就是浮水印在視覺上的透明性。經由浮水印過程而做成的「加工品」，不但令人反感、不討人喜歡，而且還可能降低或毀壞了已錄製資料的價值。因此如何在不超越可察覺門檻的限制下，設計出利用人類視覺系統的效果來嵌入浮水印的方法，就顯得非常重要，可在嵌入浮水印後不被察覺。

b.惡意竄改的脆弱性:
任何企圖惡意竄改資料的行為應該能夠被偵測出來。惡意攻擊之後，嵌入的浮水印應該變得無法被偵測出來，因此一旦影像裡無法偵測到浮水印時，我們就可以推斷資料可能已經被修改過了。

c.竄改部分的局部限制性：
可辨識出已被竄改的範圍，已確認資料的其餘部分未遭改變。

d.原始影像之還原性：
可提供遭到修改後之資料部分獲得大致上的還原，以鑑別原始資料內容。

從各種測試數據證明，我們所提出的想法的確是一個兼具某種強健型浮水印功能的影像竄改偵測與回復技術。

As the science and technology develop constantly in recent years, many related new theories and algorithms have been proposed in the digital image processing technique. It raises more and more attention in the development of the digital image. To meet the demand of technical development, the technique of image processing appears important.
Recently, the Internet grows rapidly. Digital multimedia information can easily be manipulated and tampered intentionally. So the intellectual property protection becomes more and more important. On the current development, there are many research proposed for watermarking, such as robust watermarking, fragile watermarking, semi-fragile watermarking, and tamper detection with recovery technique. The current image authentication researches are mostly extract watermarking or tamper detection and recovery, few of them are focusing on both of these two techniques. However, one of these techniques could not complete protect the image. Due to this reason, we propose a novel technique, not only can detect but also recover the tampering region. Embedding a digital watermark as authentication and also resists some basic attacks.
In this thesis, an image watermarking scheme with tamper detection and recovery is proposed. The main goal is to detect and recover the tampered region accurately. In addition, the proposed method is robust to against the cropping attack.
Embedding the suitable watermark in images can effectively prevent the malicious tampering to protect the primitive and integrity of the image. This can also provide the multi-purpose security service, the characteristics are as follows:

a) Undetectable:
The transparency of the embedded watermark in human vision is the most important issue. By embedding watermark, the “artifact” not only ill-flavored, but also possibly reduce or destroy the evaluation of the transcribed information. Therefore, how to design the embedding watermark method by utilizing the human visual system under the just noticeable threshold become extremely important, which cannot be detectable after watermark embedding.

b) Fragile for malicious alteration:
Any attempts to tamper data should be detected. After malicious attacks, the embedded watermark should become unable to detect, once the watermark is undetectable in the image, we may infer that the data are possibly revised.

c) Tamper regions restriction:
It can identify the tamper region, and confirm the other regions of the data that are not altered.

d) Recovery of the original image:
It can provide rough restoration for tampered data to identify the original data content.

As documented in the simulation results, the proposed method is robust to against attacks and is able to detect tampering. Moreover, the recovery ability is one of the feature of the propose method.

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