Effect of Quantization on the Robustness of DCT Digital Watermarking Techniques

Digital watermarking addresses the growing concerns of theft and tampering of digital media through the use of advanced signal processing strategies to embed copyright and authentication information within media content. This paper aims to implement two watermarking techniques in DCT domain. In one, embedding of signal is based on quantization and in the other embedding is without quantization. Quantization can increase the middle frequency range and thus providing more bandwidth to embed the watermark signal. But, at the same time it also affects the robustness of the watermark. Robustness of the two methods against different attacks is tested and comparative analysis is done based on their PSNR values.