Optical character recognition system for seven segment display images of measuring instruments

The explosive growth in the process control industries has increased the requirement of automatic calibration of devises drastically. In process control industries calibration of different measuring instruments for temperature, voltage, pressure, current, etc. is mostly done manually. Some of the industries use software based approach for calibration. In this paper a generalized module for automatic calibration of any measuring instruments (e.g. Temperature Monitoring System) using optical character recognition approach has been proposed. Module is designed for scanning of seven segment display of measuring instruments through camera. The System will preprocess the seven segment character display images and then extract the features for recognition. This paper mainly suggests algorithms for recognition of seven segment display characters present on digital multi-meters. This solution benefits toward significant reduction in work quantity for calibration as well as from better replication and objectivity of measuring. The accuracy of the system is 95%.