Copyright Protection against Print-and-Scan Operations by Watermarking for Color Images Using Coding and Synchronizatin of Peak Locations in Frequency Domain
Yen-Chung Chiu1 and Wen-Hsiang Tsai1,2 1Department of Computer Science National Chiao Tung University Hsinchu, 300 Taiwan 2Department of Computer Science and Information Engineering Asia Universiy Taichung, 413 Taiwan
A watermarking method for copyright protection of color images against print-andscan operations is proposed. A watermark is embedded in an input image as coefficient- value peaks that are circularly and symmetrically distributed in a middle band of the discrete Fourier transform (DFT) domain of the input image. By detecting the robust peaks in the DFT domain of a reproduced image obtained by scanning a printed version of a watermarked image, we can extract the embedded watermark to verify the copyright of the reproduced image. Experimental results are given to prove the feasibility of the proposed method.