A Pixel-Based Robust Imagewatermarking System

Robust image watermarking systems are required to be resistant to geometric attacks in addition to common image processing tasks, such as JPEG compression. However, robustness against geometric attacks, such as rotation, scaling and translation, still remains one of the most challenging research topics in image watermarking. We propose a new pixel-based watermarking system in which a binary logo is embedded, a bit per pixel, in the pixel domain of an image. The encoder of the proposed system is based on a sliding window embedding scheme that applies the local average quantization index modulation (QEM), to achieve geometric attack robustness. The decoder employs a maximum a posteriori (MAP) estimation supported by Markov random field (MRF) model to achieve robust decoding. Additionally, we demonstrate that the proposed scheme is also robust against possible watermark removal due to JPEG compression