An Algorithm for Color Image Watermarking Based On the Combination of DWT and DCT
Jin Yan Zheng · Zhongnan Linye Keji Daxue xuebao · 2008
With the development of computer network and multimedia technique,digital watermarking is becoming an efficient way to protect the copyright of digital multimedia.Digital watermarking technique embeds copyright information into multimedia signals so as to perform its protection and authentication.Based on discrete wavelet transform and discrete cosine transform for color image,this paper proposes an algorithm for digital watermarking.Firstly,the green components of an original image are divided into blocks,for each of which DCT is calculated and from each of which DC components are chosen to make up a new image,and new images are transformed with haar wavelets.Then,a binary image of scrambling chaotic encryption is embedded into a low-frequency sub-band.This algorithm can well satisfy the transparence and robustness of the watermarking system.Experimental results from using the algorithm demonstrate that it is robust to such common signal processing treatments as noise adding,JPEG compression,filtering,image enhancement and mosaic effects.