1. An automatic image preprocessing method for generating sub-volumes of a plurality of three dimensional medical volumes for the purpose of semantic extraction of anatomical structures, comprising: providing or acquiring and reconstructing a medical three dimensional image as volume, which may contain different anatomical structures or a part of an anatomical structure; automatically detecting landmarks in the volume; matching the detected landmarks with at least one atlas image to generate an indexed volume; splitting the indexed volume into indexed sub-volumes according to atlas image data; and storing the indexed sub-volumes in a database.