Integration of Wavelet Transforms for Single and Multiple Image Watermarking

Abstract

Multimedia security has become challenging due to large amount of content generation and its distribution over network. Copyright protection and content authentication are the major key factor that avoids illegal distribution of digital data. However, due to availability of high bandwidth network, copyright violation is very common and many copies of data can be illegally distributed over network. Thus, to ensure multimedia security, image watermarking methods have been introduced which is a kind of information hiding technique. Watermarking provides an effective way to ensure copyright protection and content authentication and can be implemented in spatial and transform domain. The use of wavelet transforms in watermarking increases the embedding capacity and enhances the imperceptibility of the watermarked image. Being motivated from the use of wavelet transforms in image watermarking, in this chapter, a hybrid combination of the wavelet transforms have been discussed for single and multiple image watermarking. The transforms, combined in this chapter, are nonsubsampled contourlet transform (NSCT), discrete cosine transform (DCT) and multiresolution singular value decomposition (MSVD). This hybrid combination will take advantage of the characteristics and NSCT, DCT and MSVD to build a robust watermarking system in wavelet domain against signal processing and geometrical attacks.