A blind and secured image watermarking method using DWT-DCT techniques

Abstract

This paper proposes a blind image watermarking algorithm based on the transform domain approach. The insertion of watermark is done by replacing the coefficients of DWT-DCT (Discrete Wavelet & Discrete Cosine Transform) transformed host image. Secret keys are used in this method to make it secure against any unauthentic access of watermark as the keys must be known to the user before watermark extractions. The method provides good imperceptibility and also helps to attain good results against various attacks. In this study, peak signal to noise ratio (PSNR) and cross correlation coefficient (CC) are measured to analyse the effect of different attacks on watermarked image signal as well as watermarking quality. Transform domain approach helps this scheme to achieve good robustness against attacks and key based insertion makes this approach secured towards unauthentic access. Proposed method can be used for such image watermarking applications, where good robustness, blindness and security are the prime objectives.