Detection of items in an object

This disclosure relates to a system and method for detecting an item having at least one symmetry property inside an inspection object based on at least one transmission image. The method includes the steps: (a) detection of edges of individual items contained in the transmission image in order to produce an edge image; and (b) detection of the item by determining a symmetry line that can be associated with an item with at least one symmetry property contained in the transmission image based on pairs of edge picture elements of the edge image that are positioned symmetrically to each other relative to the symmetry line; and in step (b), in determining the symmetry line in the edge image, the only edge picture elements that are taken into account are those for which the symmetry line lies in an item contained in the transmission image, to which item the edge belongs.