Macau Periodical Index (澳門期刊論文索引)
Author: Wu, CheokMan;Ng, Kengchung
Title: A high accurate Macau license plate recognition system
Journal Name: 澳門科技大學學報
Pub. Info: 第2卷第1期, pp. 23-28
Date: 30/06/2008
Link: http://lib.must.edu.mo/library/MUST_Journal/200801/articles/3.pdf
Keyword: License plate recognition;Image rotation;Horizontal projection,
Abstract: A license plate recognition (LPR) system plays an important role in numerous applications, such as parking accounting systems, traffic law enforcement, road monitoring and security systems. In this paper we present an improved method for license plate recognition system for Macau-style license plate. In the past [1], we developed an experimental system with some restrictions and one of our main conclusions was that most parts of the system error come from the situation of the license plate needs. According to this observation, we proposed a modification is based on the simple idea by using image rotation with horizontal projection to reduce system error. As we will explain the implementation of this method in detail in this paper, although the new method is very simple, its effects are quite satisfactory. Paragraph Headings: 1. Introduction 2. System architecture 3. Enhanced character location 3.1. Horizontal rotation 3.1.1. Definition of RT in (τ,p) domain 3.2. Orientation normalization 4. Experimental results and conclusions Tables: 1. Typical structure of Macau-style license plate 2. Color Schema for different kinds of plates 3. Experimental results Figures: 1. Flowchart of the proposed system 2. License plate with slanted characters 3. The relationship between Spatial f(x,y) and τ-p RT 4. Left: point (x',y') in spatial domain. Right: its corresponding infinite long line in (τ, p) domain 5. Left: line with fixed slope p' and offset τ' in spatial domain. Right: its corresponding point (p', τ') in (p, τ) domain 6. f(x,y) RT with p slop 7. RT on license plate 8. Image after horizontal rotation 9. Projection in -10 degree 10. Projection in 10 degree 11. Statistic of gap in different angles 12. License plate after normalized operation 13. Experimental results (1) 14. Experimental results (2) 15. Experimental results (3),
Location: 1/F Zone B, Macau Corner