Blind Image Watermarking Using LWT and DCT

Abstract

As a potential key to defend illegal copying of digital multimedia objects, digital watermarking technology is now attracting significant awareness. With the help of a combined Lifting Wavelet Transform (LWT) and Discrete Cosine Transform (DCT), an approach for watermarking scheme to protect copyrights of digital images is presented in this paper. The lifting wavelet transform is applied to decompose the original image into four sub-bands images. Then the discrete cosine transform is computed on the selected sub-band of the LWT coefficients. The watermark is embedded in the DCT transformed of the selected LWT sub-band of the cover image. The proposed system focuses on an invisible watermark embedding, blind watermarking, imperceptibility of watermarked image and performance evaluation metrics. This presented algorithm is implemented in MATLAB.