Abstract: A method and apparatus for classifying population states based on shape characterizations of sub-manifolds of points, curves, surfaces, or sub-volumes. A structure is examined using, for example, clinical imaging techniques such as CT, MRI, or Ultrasound. The image is then subjected to a transform function to generate a map of the new image. The new image map which contains information regarding the shape of the structure is compared to average shapes characterizing population groups. If the shape of the new image falls within a best match probability with an average shape, the new image is classified as a member of the population characterized by the average shape. Each population represents a specific classification state. Thus, if the shape of the new structure resembles the average shape of a population group, the new shape is classified as the same population state as the other structures displaying the same shape characteristics.