Conception & Implementation of a Novel Digital Image Watermarking Algorithm using Cascading of DCT and LWT

The recent development in the internet technology is definitely a boon for the society. But as far as copyright protection of multimedia content, prevention of unauthorized access, intellectual property rights etc. are concerned, this is an area that needs immediate attention. Now a days it is a relatively easy process to copy the data available on web, modify it and then put it back for individual as well as business profits. Digital Watermarking provides a viable solution by embedding information, which can be further used to prove the ownership or to detect invasion in the copyright multimedia content like text, audio, video etc. In this paper, we have proposed a new algorithm for the watermarking of digital images using cascading of two transforms i.e. Discrete cosine transform (DCT) and Lifting wavelet transform (LWT). Proposed algorithm takes the approximation component of the LWT transform of cover image and then applies DCT to embed watermark data. Watermarked data is embedded in middle frequency component using comparison based correlation technique. This algorithm has also been compared with the existing ones by applying different image attacks and subsequently measuring the robustness level and proved to be fairly robust.