Hybrid pattern recognition using the Fraunhofer diffraction pattern

A hybrid pattern-recognition method is proposed. The Fraunhofer diffraction pattern of an object was obtained in a coherent optical system and then it was processed by a digital image-processing system. The shift- and rotation-invariant characteristic values of the diffraction pattern was calculated and the classification of the object was carried out by using those values. The proposed method was tested in a simple experimental system by using some components of an electromagnetic relay as the sample objects to be recognized.