數字圖像水印的分析與實現
摘要：針對現在數字媒體版權保護的問題，本設計在數字圖像小波變換的基礎上，在原始圖像上嵌入水印圖像。嵌入的圖像水印即能表徵作品的所有權。數字水印是利用數字作品中普遍存在的冗餘數據與隨機性把版權資訊嵌入在數字作品本身中，從而起到保護數字產品版權或者完整性的1種技術。
具體實現過程：先對原始圖像（即需版權保護的作品）和水印圖像做3層小波變換，然後將水印與原始圖像的3層小波係數相加，爲了水印圖像的不可見，運算時將水印係數乘以1個嵌入因子。水印的提取過程與嵌入過程恰好相反，即對嵌有水印的圖像作品和原始圖像做3層小波變換，然後將帶水印圖像的小波係數與原始圖像的`小波係數相減，結果除以嵌入因子，即得水印圖像。
該方法屬於在圖像變換域上的水印的嵌入法，要得到魯棒性好的水印，又要使作品的版權驗證簡單明瞭，需要對水印的嵌入方式做精心設計。
關鍵詞：小波變換；水印；魯棒性
Analysis and realization of digital image watermark
Abstract：In response to the issue of copyright protection about the media, the images wavelet transform in the design is the basis of the original images embedded watermarks in images. Embedded images watermarks that can scale works ownership. Digital watermarks widespread is the use of digital works in the random nature of the redundant data and information embedded in the digital copyright works themselves, thus protecting a copyright or completeness of a digital product technology.
Concrete realization process : first the raw images (that is, the need to protect copyright works) and Watermark images do three-tier wavelet transform, then Watermark images with the original three-tier wavelet transform calculated to Watermark images not visible, computers will be multiplied by a factor of watermarks embedded factors. Watermark extraction process with embedded processes to the contrary, that there are watermarks on the images inlay works and the original three-tier wavelet images do change, and then bring Watermark images wavelet coefficient with the original images wavelet factor subtract that result divided by embedded factors that may Watermark images.
The methods of transformation where the watermarks in images with embedded France to be good watermarks robustness, but also enable copyright certification simple, the need for the embedded watermarks way so carefully designed.
Keywords: wavelet transform; watermark; robustness
註釋：不含原始碼