we propose a region based segmentation method which is capable of segmenting objects in presence of significant intensity inhomogeneity. Present method use some form of local processing to tackle intra region inhomogeneity, which further makes such methods susceptible to local minima. Here we present a framework which generalizes the traditional Chan-Vese algorithm. In contrast with existing local techniques, we represent the illumination of the regions of interest in a lower dimensional subspace using set of pre-specified basis functions. This representation can accommodate heterogeneous objects, even in presence of noise. We compare our results with several techniques like biological/biomedical images with tubular or filamentous structures. As the, we achieve a 44% increase in performance, which demonstrates efficacy of the method.
I. INTRODUCTION Active contours [1]-[4]are popular for image segmentation. Active contours have ability to elastically deform and delineate object boundaries with sub-pixel accuracy. Furthermore, the energy optimization framework, which serves as the basic platform for most active contour based techniques, can be handle easily to introduce ad-additional constraints based on shape, appearance etc. to assist segmentation. Geometric active contours are used when the application requires the propagating curves to be able to adapt to the varying topology of the underlying object by automated splitting or merging. The geometric active contours may be divided in two types. Edge based techniques and region based techniques. Edge based techniques [2], [5], [6] perform curve evolution geometrically, with the stopping criteria controlled by edge dependent features extracted from the image. However, in many applications where the edge information is unreliable, region based techniques are used. Chan and Vese [3] proposed a level set formulation to minimize the Mumford Shah functional [7] for segmentation. The Chan-Vese frame-work models the image as a set of constant illumination regions and performs a two-class segmentation by computing the optimal partition which hereby satisfies the constant illumination constraint. The authors also propose a multi-phase variant [8] of their approach to perform multi-class grouping.