An image watermarking technique using hybrid signals as watermarks

Abstract

In digital communication, it is very necessary to prevent the unlawful intrusion of unwanted parties. Apart from that, the authenticity of a signal being sent is a key factor otherwise false data can break the commitment between the sender and the receiver of the signal. By digital watermarking, both the insurance of the authenticity and the prevention of unlawful intrusion can be maintained by inserting information into the host signal. In this paper, an image watermarking technique is proposed. In the proposed technique, hybrid signals are used as watermarks. Hybrid means using images as well as an audio signal as watermarks. This can certainly increase the robustness of the proposed technique as in case of very rigorous attacks at least one watermark can be survived ensuring the true owner of the signal being sent. The watermarks are inserted in different levels of the host image using the entire energy distribution of the host image. The energy of the watermarks is divided to embed different parts of the energy in different levels of the host signal. For doing this, discrete wavelet transform (DWT) and singular value decomposition (SVD) are used. The proposed technique offers a PSNR (Peak Signal to Noise Ratio) of 67.8606 dB and NCC (Normalized Cross-Correlation) above 0.9.