A Robust Image Watermarking in Contourlet Transform Domain

A lot of work has been done in the field of image watermarking to overcome the problems of rightful ownership, copyright protection etc. In order to provide a robust solution of such issues, the authors propose a hybrid approach that involves contourlet, lifting wavelet, and discrete cosine transform. The first level coefficients of the original image which are obtained using contourlet transform are further decomposed using one level lifting wavelet transform. After that, these coefficients are modified using discrete cosine transform. Whereas, second level subband of contourlet transform coefficients are used to obtain block wise modification parameter based on edge detection and entropy calculations. Watermark bits are embedded by quantizing the discrete cosine transform coefficient blocks obtained using HL sub-band of first level lifting wavelet transform coefficients. The experimental results reveal that the proposed scheme has high robustness and imperceptibility.