Pattern recognition by artificial neural network for coin testing apparatus

摘要

A coin validation system for determining if a coin moving along a coin rail is a valid coin, and if so, its denomination the system including a rail along which coins move, at least one optical sensor located along the rail to sense the presence or absence of a coin moving therealong, at least one magnetic sensor associated with each optical sensor located in the vicinity of the respective optical sensor, each of the magnetic sensors including an inductive element and a circuit for exciting the magnetic sensor to produce a field that is coupled to the coin moving past so that the coin and the inductive element have mutual inductance therebetween, the circuit ringing the magnetic sensor a predetermined number of times while the coin is adjacent to the magnetic sensor whereby the magnetic sensor generates a damped wave signal having characteristics representative of the physical and magnetic characteristics of the coin, a signal preprocessor operatively connected to the magnetic sensor for producing output responses representative of distinguishing characteristics of the coin, a feature extraction circuit for extracting from the output responses of the signal preprocessor signal portions representative of predetermined distinguishing characteristics of the coin, a circuit for producing a multi-dimensional representation of the extracted features and for comparing the multi- dimensional representation with the center of an established ellipsoidal cluster of selected coin denominations to determine the extent of the comparison therebetween and to be used to determine whether the coin is an acceptable coin or not, and an artificial neural network classifier circuit having connections to the preprocessor and to the comparator circuit, the neural network classifier circuit having an output which identifies the denomination of coins that are determined by the comparator circuit to be acceptable.