A method and apparatus for detecting abnormal regions in living tissue depicted in a digital radiograph includes identifying suspected abnormal regions depicted in the radiograph and then, for each identified suspected abnormal region, extracting multiple topographic layers of the region from the digital...http://www.google.co.uk/patents/US5838815?utm_source=gb-gplus-sharePatent US5838815 - Method and system to enhance robust identification of abnormal regions in radiographs 
