Segmentation of cervical cells: Detection of overlapping cell nuclei

Abstract

A method for detecting overlapping cell nuclei in Pap-stained cervical smears is described. The algorithm uses information both from the nuclear contour and from the density profile of the nucleus. For the analysis of the nuclear contour the smoothed difference chain code is used. From this code any significant concavities along the contour are found and a number of features describing their size and relative location are computed. If these clearly indicate an overlap situation the object is classified as an overlap. Otherwise a density profile is generated along a line orthogonal to the line joining the two major concavities. This profile is checked for peaks and valleys indicative of an overlap situation and a new set of features are generated and used to classify the object as single or overlapping. The algorithm performed reasonably well when tested on an independent test set of about 240 cell images.