Abstract
Image, audio and video are the first media affected by hacking due to the availability of the internet and to the high speed connection. One of the solutions to solve such problems is watermarking. Digital watermarking is the process of embedding an imperceptible and a robust signature into a digital signal. In this paper, we focus on image watermarking. We have embedded the watermark in the frequency domain using Discrete Cosine Transform. The choice of the blocks where we insert the watermark bits depends on a preprocessing study on the original and compressed-decompressed image. Then we have implemented a blind detection algorithm. We tried to enhance the security of our technique by applying an Arnold transform to the embedded watermark. Finally, we have tested the robustness of our method by applying many attacks to the watermarked images using Stirmark 3.1. The results demonstrate that our method yields a high level of imperceptibility and robustness against JPEG compression, unique and double Stirmark attacks.