以動態能量差異化為基礎之小波樹數位影像浮水印

Abstract

隨著網際網路的發達以及資訊數位化技術的進步，人們可以輕易的對數位資訊進行編輯、複製，並透過網路快速的傳送至世界各地。然而，資訊科技的進步卻也產生了一些安全性的問題，其中包含各種數位內容的非法複製、散佈或提供不被授權的下載等侵害智慧財產權的情事發生。

在數位內容的智財權保護方法中，數位浮水印技術可以將數位內容的版權資訊以浮水印方式嵌入數位內容中，當產生版權爭議時，即可將浮水印透過特定機制解讀出來，以作為智財權認定上的證明依據，使數位內容的版權受到保障。

本論文是以小波轉換理論為基礎，動態改變頻率域影像之小波係數，藉由係數之間特定的差異化以達到浮水印嵌入之目的。此外更利用影像切割重組之方法，有效提升浮水印抵抗空間域幾何攻擊之能力，進而建構出更具安全性與強韌性之小波樹數位影像浮水印演算法，提供更有效的數位智財權保護技術。

Because of the development of Internet and digitization of information technique, people can easily edit, copy, and transmit the digital information to any place of the world. But the progress of information technique also causes some problems about security, including the illegal copies, transmission, and unauthorized downloads of all kinds of digital content that infringe the intellectual property rights.

Among all the methods for digital content copyright protection, digital watermarking technique can embed the copyright information into the digital content with watermarks. If any dispute of copyright occurs, we can extract the watermark through specific procedure to distinguish it and make the copyright of digital content to be protected.

This thesis is based on wavelet transformation theory. We modify the wavelet coefficient values of images in frequency domain dynamically and use the differentiation to embed the watermark. We also use the image cutting-and-assembling mosaic method to improve the ability of resistance to malicious geometric attacks, and make our method more robust and securer.