Automatic Recognition System for Numeric Characters on Ammeter Dial Plate

The automatic recognition system for numeric character on ammeter dial plate which can be used on electronic display ammeter and mechanical ammeter is proposed in this paper. This system use binary transformation, projecting algorithm, thinning, Hough transformation, open algorithm and close algorithm as preprocessing, put forward nine segment display projection algorithm based on seven segment display to extract digital characteristics and use layered pattern base to realize numeric character recognition. Characters similar in form can be distinguished better by using nine segment display projection algorithm. The experiments show that the accurate numeric character recognition rate is up to 98% by using the system and the recognition time of 6 digits mechanical ammeter is less than 18 milliseconds. This system is a fast and high accuracy method of numeric character recognition through testing. The system also can be used to other areas such as real time vehicle plate recognition, ID card recognition and passport recognition.