Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/7669
標題: 合併直序展頻與跳頻展頻之影像浮水印架構
Image Watermarks Combining Direct Sequence
作者: 張詠翔
Chang, Yung-Hsiang
關鍵字: Watermark;影像浮水印
出版社: 電機工程學系
摘要: 
摘要
隨著網際網路、多媒體與電子商務的快速成長,資訊交換變得既快速又方便,也由於資訊的取得太容易了,對於個人私密性資料的保護與智慧財產權的保障就顯的非常的重要。
我們使用通訊系統中的展頻通訊原理來實現數位浮水印。將數位浮水印系統比擬成通訊系統,原始媒體資訊(影像)之頻率域為傳輸通道,而浮水印資料為傳輸訊號,可能遇到的攻擊或破壞則視為通道雜訊。
展頻通訊區分為直接序列展頻(Direct Sequence Spread Spectrum DSSS)與跳頻展頻(Frequency Hopping Spread Spectrum FHSS)二種,因此,我們針對這二種展頻技術而設計。並融合跳頻展頻與直序展頻的Combine-S Watermarking技術。Combine-S Watermarking可同時擁有跳頻展頻浮水印與直序展頻浮水印的優點,我們藉由調整Slow DSSS Watermarking與Slow FHSS Watermarking的比例抵抗不同的影像攻擊,藉此可以抵抗較多種的破壞,達到提高數位浮水印強韌度之目的。
最後我們得到Slow DSSS Watermarking與Slow FHSS Watermarking採用2:8的比例,可以抵抗大多數的攻擊,而且取出的浮水印仍有一定品質,因此2:8是一個可接受且優良的比例分配。

Abstract
With the rapid growth of Internet, information exchange is getting more and more convenient. As it is so easy to obtain others information in the networks, the issues of the privacy and copyright protection become more important to prevent unauthorized access.
In the thesis, we developed two watermarking techniques using spread-spectrum technique. The watermarking technology can be viewed as a communication system. The watermark was the signal to be transmitted. The frequency domain of the original image was the transmission channel. The attacks were regarded as channel noise. There were two methods to implement the spread-spectrum system: direct- sequence spread- spectrum (DSSS) and frequency-hopping spread-spectrum (FHSS). Based on these two methods, we developed a method that combined FHSS Watermarking and DSSS Watermarking. We called the new method “combine-S Watermarking”. The experimental results proved that combine-S Watermarking had both the advantages of FHSS Watermarking and DSSS Watermarking. Therefore, combine-S Watermarking was more robust and can withstand many different attacks.
URI: http://hdl.handle.net/11455/7669
Appears in Collections:電機工程學系所

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