A New Watermarking Algorithm Based on DCT and DWT Fusion

In this paper a new blind watermarking algorithm based on DCT (discrete cosine transform) and DWT (discrete wavelet transform) was proposed. In order to enhance the security of watermarking, Arnold transform is carried out on the watermark image. Firstly discrete wavelet transform is carried out on the host image three times. Secondly the low resolution sub-image of DWT (LL3) is divided in to 8*8 blocks and then discrete cosine transform is carried out on the blocks. At last the middle frequency coefficients of the blocks are selected to embed the watermark image. In term of traditional algorithm the experiment results show that the new algorithm keeps the quality of host image well and a high robustness against common attacks such as JPEG compression, additive Gaussian noise, image rotation, image cropping and so on.