An enhanced technique for color image water marking using HAAR transform

Abstract

Digital watermarking has been widely applied for copyright protection problems of digital media relating to illegal use or distribution. Here, the paper illustrates the extension of colour image watermarking from grey scale image watermarking using wavelet transform and DCT (Discrete Cosine Transform) and difference between both. The basic watermarking principle of LSB (least significant bit) substitution is followed. This paper involves a new scheme of watermarking using DHT (Discrete HAAR wavelet Transform) and Discrete Cosine Transform for data hiding. In the proposed method, images are split into 3 planes of primary colour RGB. The transform is performed on each of these planes of the embedded image. On the retrieval side, with the help of key the receiver extracts the watermarked image by performing an inverse transform. Experiments deduce that the proposed method yields an efficient invisible watermarking technique that is robust to a variety of attacks such as image cropping, filtering, noise adding etc. Furthermore, HAAR transform involves only simple arithmetic operations, which when implemented on the FPGA chip takes less computational time and consumes less space with high PSNR (Peak signal-to-noise ratio).