Real-time search-free multiple license plate recognition via likelihood estimation of saliency

• Published in: Computers & electrical engineering Vol. 56; pp. 15 - 29
• Main Authors: Safaei, Amin, Tang, Hongying L., Sanei, Saeid
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01-11-2016; Elsevier BV
• Subjects: Algorithms; Automatic license plate recognition; Bayesian; Bayesian analysis; Intelligent transportation system; Localization; Localization method; Methods; Object recognition; Object tracking; Real time; Saliency map detection; Search methods; Searching; Shadow removal; Tracking; Saliency map detection; Intelligent transportation system; Shadow removal; Bayesian; Automatic license plate recognition; Localization; Object tracking
• ISSN: 0045-7906; 1879-0755
• DOI: 10.1016/j.compeleceng.2016.09.010

•A search-free car license plate localization method based on 3-D Bayesian saliency estimation has been developed for the first time.•This method uses a 3-D object tracking algorithm based on Bayesian methods to estimate the 3-D salient regions by exploiting the motion information in the videos.•The algorithm is fast and robust to variation in the environment and is suitable for localizing multiple plates.•The tracking approach exhibits acceptable accuracy for different noise and artefact levels.•The localization method uses adaptive size in closing to improve the accuracy.
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In this paper, we propose a novel search-free localization method based on 3-D Bayesian saliency estimation. This method uses a new 3-D object tracking algorithm which includes: object detection, shadow detection and removal, and object recognition based on Bayesian methods. The algorithm is tested over three image datasets with different levels of complexities, and the results are compared with those of benchmark methods in terms of speed and accuracy. Unlike most search-based license-plate extraction methods, our proposed 3-D Bayesian saliency algorithm has lower execution time (less than 60 ms), more accuracy, and it is a search-free algorithm which works in noisy backgrounds.