Dual Digital Water Marking Using Wavelet Transform

Image watermarking has become an important tool for intellectual property protection and authentication. Digital watermark is the technique in which visible / invisible signal is embedded in a multimedia document for copyright protection. Dual watermarking is a combination of visible watermark and an invisible watermark. In this paper, we propose watermarking scheme called dual watermarking that incorporates two invisible watermarks in the host image for improved protection and robustness. A watermark, in form of a PN sequence (secondary watermark), is embedded in the wavelet domain of a primary watermark before being embedded in the wavelet domain of host image. The discrete wavelet transformation algorithm is proposed for embedding invisible watermark. The results obtained are shown and their detecting strategy for authentication is also discussed in this paper.