Design of an improved algorithm for blind digital image watermarking using both grayscale and binary watermark in DFWHT domain

This paper focuses on the design of an improved DFWHT (Discrete Fast Walsh Hadamard Transform) domain robust, blind digital image watermarking algorithm. Both encoding and extraction algorithm have been verified using MATLAB R2013a. Here both grayscale and binary watermarks are possible for embedding and extraction using the same designed algorithm and only grayscale cover image of maximum size(256 × 256) is used. The speciality of this algorithm attracts to the fact that there is no requirement for any other information other than the received watermarked image to extract the watermark at decoding, which makes it blind watermarking. The time complexity of the proposed algorithm is of the order of O(n²) and it is simple to implement in hardware.