使用小波轉換的數位浮水印對數位影像資訊所有權確認之研究

Abstract

對影像資訊而言，使用加解密的資訊安全的技術，仍不足以保障所有權人的認證，因為當數位資料傳送至接收端並完成解密動作後，保密的效果便不復存在，也就是說，確認所有權擁有者的機制已經消失。然而，使用數位浮水印，將其嵌入資料當中，即使經過複製或有限度地破壞，數位浮水印仍存在於資料之中，可作為提供版權證明之證據，使得加密保護的工作更為完備。本論文目前已成功地利用小波轉換 (DWT)，設計出一套數位浮水印的架構，能夠抵抗多種影像處理的攻擊，符合不易察覺(Imperceptible)、強韌性(Robust)以及明確性(Unambiguous)等的要求。此外，本架構能使用可辨識的圖形為數位浮水印，提供作者在驗證所有權之確認時，增加視覺上判斷的輔助。

For image data, the technology of encryption is not enough to protect the authentication of the owner. The reason is when the image data sent to the receiver and the decryption finished, the protection of encryption is no longer existing. However, we can embed digital watermarks into the data to verify the authentication of the owner. Even if the data has been duplicated or corrupted, there is strong evidence of the existence of the watermarks. After through study and research, we have successfully designed an algorithm of digital watermarking by using discrete wavelet transform (DWT). The embedded watermarks have much better durability to defy the image processing attacks. This architecture meets the requirement of imperceptibility, robustness, and unambiguousness. Besides, we can use a visually recognizable image data as the watermark, which can give further assistance to identify the ownership of the author.