Abstract: A computer assisted method of detecting and classifying lung nodules within a set of CT images to identify the regions of the CT images in which to search for potential lung nodules. The lungs are processed to identify a subregion of a lung on a CT image. The computer defines a nodule centroid for a nodule class of pixels and a background centroid for a background class of pixels within the subregion in the CT image; and determines a nodule distance between a pixel and the nodule centroid and a background distance between the pixel and the background centroid. Thereafter, the computer assigns the pixel to the nodule class or to the background class based on the first and second distances; stores the identification in a memory; and analyzes the nodule class to determine the likelihood of each pixel cluster being a true nodule.