Hybrid method using HWT-DCT for image watermarking

Abstract

This paper proposed a hybrid method that had been solved both of these issues. We proposed a combination of Discrete Cosine Transform (DCT) and Haar Wavelet Transform (HWT) due to achieved imperceptibility and robustness comes from PSNR and NC value. Firstly, HWT applied in host image and then selected subband LL. LL subband will be divided into an 8×8 matrix in which each matrix was applied using DCT. Copyright embedded at the DC coefficient. In this paper we choose PSNR to measure the imperceptibility. Meanwhile, to measure the extracted copyright we used correlation coefficient. The results of this simulation method getting high PSNR value with an average of 43.2392 dB. Experiment results of extraction has tested using image watermarking attacks are JPEG compression, low pass filtering, mid filtering, unsharp filter, gaussian noise, cropingp, blurring, salt and pepper with the average value of the correlation coefficient of 0.8676. Our results proved that HWT-DCT has fulfilled the purpose of image watermarking, namely copyright protection.