I. INTRODUCTION
Magnetic Resonance Imaging (MRI) is a popular tool for exploring anatomy of human body and diagnosing diseases. In the past decades, numerous computerized image processing methods have been developed to facilitate the understanding of MR images. However, intensity inhomogeneity has been an issue affecting the quality of post processing. It could be caused by spatially varying sensitivity of radio frequency (RF) imaging coils, magnetic permeability and dielectric property of imaged objects, rendering smoothly changing bright and dark regions in the magnitude images. It becomes severer in the cases of large field of view (FOV) such as whole body imaging. Under the scenario, both anatomy and inhomogeneity field contribute to the intensity value changes across the images. Without inhomogeneity correction (IC), the intensity-driven segmentation/registration methods cannot distinguish the effects of these two components and will fail.