A Robust Digital Watermarking Algorithm Based on Multiple-Level Discrete Cosine Transform

The 'Multiple-level' idea is introduced from Discrete Wavelet Transform to Discrete Cosine Transform,and the properties of multiple-level Discrete Cosine Transform are analyzed.A digital watermarking algorithm is proposed based on multiple-level Discrete Cosine Transform.In the proposed algorithm,the watermark information is embedded in the selected coefficients of multiple-level Discrete Cosine Transform.Experimental studies show that the proposed algorithm has better robustness compared with common digital watermarking algorithms based on Discrete Cosine Transform,and its real-time property is not affected by the multiple-level transform.Besides,the methods of choosing transform coefficients and transform levels are studied,and experimental results show that the best performance can be achieved by reasonably choosing transform coefficients for the two-level transform.