Digital Image Watermarking Scheme Based on LWT and DCT

Abstract—As a potential solution to defend unauthorized replication of digital multimedia objects, digital watermarking technology is now attracting significant attention. With the aid of a combined Lifting Wavelet Transform (LWT) and Discrete Cosine Transform (DCT), an approach for watermaking 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-band 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, imperceptibility of watermarked image and performance evaluation metrics. This presented algorithm is realized in MATLAB.