Moderate computational load watermarking system for digital images

This paper describes a watermarking system for digital images. The watermarking technique used operates in the frequency domain by embedding a pseudo-random sequence of real numbers in a selected set of DCT coefficients. In order to improve the results, besides using fit enough coding and decoding algorithms, we propose the use of orthogonal watermarks. Tests have been carried out in order to select appropriate values for the different parameters in the system having in mind the robustness and a moderate computational load. Several attacks have been performed to prove the robustness of the method with the parameters' proposed values.