Survey on Automatic Vehicle Number Plate Localization

In this paper a survey is being carried out in the field of Automatic license plate localization. Automatic license plate recognition (ALPR) is to extract vehicle license plate information from an image or a sequence of images. The extracted information can be used with or without a database in many applications such as electronic payment systems, freeway and specific road monitoring systems for traffic surveillance. As a real-life application it has to quickly and successfully process license plates under different environmental conditions such as indoors, outdoors, day/night time. The localization or detection of the number plate of the vehicle images is the basis for any ALPR system. This is the first step in any LPR system and is considered as the most crucial step in the ALPR system. The success rate also depends mainly on this stage only. Hence the best localization or detection of the number plate is necessary to get the high recognition rate in any ALPR system. A survey has been made in this field by considering different methods that have been addressed to detect the number plate from the vehicle images. All these methods are categorized based on the features that they have used. At the end, a comparison is made in terms of advantages, drawbacks and possible enhancements.