Recognition of license plate images: issues and perspectives

Recognition of license plate images is the topic of the paper. The major issue in this problem is the accurate extraction of the license plate string from varying backgrounds. The images are also characterized by non-uniform illumination. Recognition of the string is fairly straightforward, if the extraction process has been correctly designed. The authors discuss three different approaches to extraction and their study revealed that fusion of gray scale morphology and homomorphic processing yielded accurate extraction of the string. Recognition studies with 700 images captured during day and night times indicated an overall acceptance rate of 80% or higher with less than 1% confusion is achievable. Results obtained from a more exhaustive study that is currently in progress are presented