A robust block-based image watermarking scheme using fast Hadamard transform and singular value decomposition
We present a new approach for transparent and high rate embedding of watermarks into digital images using fast Hadamard transform (FHT) and singular value decomposition (SVD). The proposed algorithm consists of three main steps: dividing the cover image into small blocks, applying the FHT to each block, and distributing the singular values of the visual watermark image over the transformed cover blocks. The main attractive features of this approach are simplicity, flexibility in data embedding capacity, and real-time implementation. The experimental results show the much improved performance of the proposed method in comparison with existing techniques, and also its robustness against the most common attacks