Localized Watermarking Scheme
局部化数字水印算法

A digital watermark is an invisible mark embedded in digital images, video or audio documents, which may be used for a number of different purposes including copyright protection, authentication and captioning. In this paper, we proposed a watermarking scheme that embeds watermarks in the local region of the image. This new idea that we name it local watermarking scheme, inserts watermarks into the wavelet domain of local regions of the image instead of entire image. We select some stable feature points in the image, and then use these points to identify the locations where we insert watermarks. When the image is cropped, the feature points in the remaining piece of the image will not change. We can extract watermark with the help of the remaining feature points. A special quantization procedure is used when we embed watermark bits into the wavelet coefficients of the sub image, and the watermark can be detected without knowing the original image. Experimental results show that the watermark scheme proposed in this paper is robust to cropping, and also has good robustness to compression, filtering, noise adding, and StirMark attack.