| Summary: | 碩士 === 國立中央大學 === 資訊工程研究所 === 100 === Synchronized watermark detection is an important issue. The embedded watermark may not be detected successfully if the image has undergone such geometrical transformations as rotation, cropping, scaling or even random bending. This research presents a feature-based still image watermarking approach. Scale-Invariant Feature Transform (SIFT) is first applied to locate the interest points, from which we form the invariant regions for watermark embedding. To resist geometrical transformations, the extended synchronization templates, which help to ensure that reasonably large invariant regions will be available for carrying the watermark payload and/or for increasing the confidence of watermark detection, will also be embedded. In the detection phase, after SIFT, the template is first determined locally by adjusting the related affine parameters of the grid to match with the possible hidden template signal so that the watermark can be retrieved afterwards. Experimental results show the feasibility of the proposed method.
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