Optical numeral recognition algorithm for seven segment display

Abstract

The paper discusses an algorithm for the recognition of seven segment numbers on a display, so that the algorithm can be utilized for applications such as automated reading of LCD-based meters. The algorithm outlines a 7-step process consisting of four types of operations-Object Detection, Noise Removal, Image Segmentation and Numeral Recognition based on pixel density feature extraction. The performance of the algorithm is evaluated, by simulation and field tests, for robustness to variations of digit positions, brightness, contrast, tilt and noise. The recognition rate of the algorithm is 79% when tested over a wide range of variation in illumination and angular tilt conditions.