License plate detection and character recognition

Abstract

In this paper we describe an approach based on infrared camera and novel methods about how to detect license plates on rear-side of a vehicle in still image or video stream. Particular contribution is posed on discovering plate area by edge search on each side of plate and reconstruction of rectangular shape. The recognized plate area is rotated and adjusted for a better character separation. Top hat morphological operator is used to extract characters from plate background. Each single character inside plate area is separated even in case of tilted shape. This approach try to slice the plate vertically, and it follow the character profile that hit on his vertical path. Pattern matching based on modified Yule dissimilarity measure is used for character recognition. Performance on 200 images are discussed. © 2009 Springer Berlin Heidelberg.