A novel segmentation algorithm for pulmonary nodule in chest radiograph

Segmentation of pulmonary nodules in chest radiographs is a difficult task due to heavy noise and superposition of ribs, vessels, and other anatomical structures in lung field. In this paper, a polynomial fitting based ray-casting algorithm is proposed for pulmonary nodule segmentation in chest radiographs. Instead of directly detecting nodule edge points, the nodule intensity profiles are first fitted by using polynomials. Then, the edge positions are identified through analyzing the local minimum of the fitted curves. The algorithm has been experimentally tested over an image database with 148 nodule cases in chest radiographs collected from a variety of digital radiograph modalities. Preliminary results have shown that the proposed segmentation algorithm has obtained a high rate of successful segmentations.