1. A method of classifying a pulmonary nodule, the method comprising: receiving image data associated with a chest scan; segmenting image data associated with lung tissue from the image data associated with the chest scan; equalizing the segmented image data; segmenting image data associated with a pulmonary nodule from the equalized and segmented image data; generating a three dimensional (3D) mesh model of the segmented pulmonary nodule; mapping the 3D mesh model to a corresponding unit sphere; computing a number of spherical harmonics required to delineate the unit sphere to the 3D mesh model; and classifying the pulmonary nodule as malignant or benign using a learned shape model based at least in part on the computed number of spherical harmonics required to delineate the unit sphere to the 3D mesh model.