RGB Watermark Algorithm Based on Key Image
CHE Shengbing, HUANG Da, LI Guang (College of Electronic & Information Engineering, Central South University of Forestry & Technology, Changsha 410004)
With the actuality that the colorspaces used by the digital media, it converts RGB image and watermark into vectors of the colorspace that the digital media uses, transforms these vectors by two dimension DCT and appends watermark coefficients to related RGB image coefficients with controllable intension and composes RGB image containing watermark, composes those coefficients being appended to a RGB key image. The main contributions of the paper are that it uses RGB image and RGB watermark, it is to be the same with all the colorspaces that popular digital media used, it enhances real time response ability of the algorithm by avoiding sortting and reallocation DCT coefficients. Experimentations show that the algorithm is robust to several signal processing techniques, including cut, JPEG lose compression, stretching, addition of noise, faint and sharpen operations etc.