在本論文，我們提出一個植基於向量量化(Vector Quantization; VQ)編碼法來產生非嵌入式浮水印的影像版權保護技術。我們的方法利用編碼簿，將影像中的區塊與浮水印位元產生關連，並輸出表示關連的key stream，藉由此key stream 來證明影像與浮水印的關連性，達成宣告版權的目的。我們的方法可以彈性調整每個區塊對應浮水印的位元數。與學者Lin 等所提出的非嵌入式浮水印方法相比較，我們的方法只需要一本編碼簿，而他們的方法需要七本，再者我們的方法不會有某些區塊無法與浮水印產生關連的缺點。最後，我們的方法衍生出強健型浮水印和脆弱型浮水印兩種變型，不但縮減key stream 的長度，而且增加浮水印應用上的彈性。
In the paper, we propose a nonembedded watermarking scheme, which is based on vector quantization (VQ), to protect the image copyright. Our approach applies a codebook to generate a relationship between image blocks and watermark bits, then the relationship is outputted as the key stream. With the key stream, the relation between the image and the watermark is confirmed and the copyright of the image is declared. In our method, the number of bits related to a block is adaptive. Compared with Lin et al.’s approach, our approach need only one codebook; however, their approach need seven codebooks. Moreover, each block can be connected with watermark bits in our approach; however, some blocks can not be connected with watermark bits in their method. Finally, our approach evolves two strategies: robust watermarking and fragile watermarking, which not only to reduce the length of key stream, but also to increase flexibility of application.
