The Performances Analysis of Transformation Methods in Image Watermarking Using Subsamplimg

We investigate the performances of different types of transformations in image watermarking algorithm using subsampling which include Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT), and Discrete Multiwavelet Transform (DMWT). The DMWT has been used as decomposition tool to obtain multiresolution data. The efficiencies of these transforms are discussed by evaluating watermarked image quality and robustness of the watermark. Due to the multiresolution representation obtained from using DWT and DMWT, the algorithms using both transforms yield better image quality than the one using DCT. Due to the fact that DMWT provides the possibility of superior performance for image processing applications, the algorithm using DMWT yields best image quality and gives the most robust watermark under common image processing. Simulated results show that the DMWT method is superior to other two methods.