Digital Image Watermarking by Fusion of Wavelet and Curvelet Transform

A new hybrid watermarking algorithm using discrete wavelet transform (DWT) and curvelet transform (CT) is implemented in this paper. Curvelet transform is developed to be more efficient than traditional transformations to represent edges along curves. In the proposed work, image watermarking is achieved by applying hybrid transformation and then evaluating the efficacy of the method. Initially, image is decomposed using DWT and then fast curvelet transform is applied on cD (diagonal edges details) sub-band. Secondly, lower coefficients are selected to embed binary-encoded watermark bits. Efficiency of algorithm is tested with different texture images and by varying size of watermark. The effectiveness of proposed algorithm is evaluated by applying attacks like resize, median filtering, and addition of noise. The results shows that, it is sustaining over different texture images even with increase in watermark embedding capacity. The proposed method results in 34.33 dB peak signal-to-noise ratio (PSNR) for high texture image, 47.77 dB for medium texture image, and 48.62 dB for low texture image over maximum size of watermark. It has good robustness against attacks and on large embedding capacity.