An efficient method of vehicle license plate detection based on HSI color model and histogram

Abstract

Detecting license plate (LP) is a crucial and inevitable component of the vehicle license plate recognition (VLPR) system. In this paper to select automatically statistical threshold value in HSI color model is proposed. The proposed vehicle license plate detection (VLPD) method consists of two main stages. Initially, HSI color model is adopted for detecting candidate regions. According to different colored LP, these candidate regions may include LP regions; geometrical properties of LP are then used for classification. The proposed method is able to deal with candidate regions under independent orientation and scale of the plate. Finally, the decomposition of candidate regions contains predetermined LP alphanumeric characters by using position in the histogram to verify and detect vehicle license plate (VLP) region. Experimental results show that the proposed method is very effective in coping with different images under the variety of conditions such as complex scenes, illumination changing, distances and varied weather etc. © 2009 Springer Berlin Heidelberg.