Image Segmentation In The Presence Of Intensity Inhomogenity: A Survey

The segmentation in medical images especially in the field of MR image is a challenging task in the presence of intensity inhomogenity. So many techniques have been devised to correct this artifact. The intensity inhomogenity also known as intensity non uniformity refers to the slow, non atomic intensity variations of the same tissue over the image domain. This paper attempts to review some of the recent developments in the modeling of intensity inhomogenity field. This IIH mainly occurs due to the imperfections in imaging devices, lightning and illumination effects. The imperfections in the image acquisition process, manifests itself as a smooth intensity variation across the image. Due to the presence of intensity non uniformity the segmentation results are not accurate. So this survey paper describes various techniques for image segmentation in the presence of intensity inhomogenity. Intensity inhomogenity are considered to be multiplicative low frequency variations of intensities that are caused by the anomalies of the magnetic field of scanners. Intensity non uniformity is caused by the overlaps between the ranges of intensities in the region to be segmented. This survey paper covers segmentation techniques to overcome the intensity inhomogenity and obtain accurate results.