Development of vehicle-license number recognition system using real-time image processing and its application to travel-time measurement

Author

Kanayama, Kenji ; Fujikawa, Yuto ; Fujimoto, Kenji ; Horino, Masanobu

Author_Institution

Omron Corp., Kyoto, Japan

fYear

1991

fDate

19-22 May 1991

Firstpage

798

Lastpage

804

Abstract

In order to recognize vehicle license numbers in real time, a CCD (charge-coupled device) camera with electronic shutter and a hierarchical computer system with a general-purpose microprocessor and pipelined image processors have been developed. Much quicker extraction of the vehicle-license plate on the front-view image is realized by optimization of parameters using Taguchi´s method. Distinct images outdoors can be obtained using a suitable control of the lens-diaphragm and continuous lighting via floodlight equipment. The results of field tests show that recognition rates of about 90% in the daytime and about 65% at night were attained. The processing time per vehicle is about 150 ms on average

Keywords

CCD image sensors; computerised pattern recognition; pipeline processing; road vehicles; 150 ms; CCD camera; Taguchi´s method; continuous lighting; electronic shutter; floodlight equipment; front-view image; hierarchical computer system; lens-diaphragm; pipelined image processors; processing time; real-time image processing; road vehicles; travel-time measurement; vehicle-license number recognition; Charge coupled devices; Charge-coupled image sensors; Image recognition; Licenses; Lighting control; Microprocessors; Optimization methods; Real time systems; Testing; Vehicles;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1991. Gateway to the Future Technology in Motion., 41st IEEE

Conference_Location

St. Louis, MO

ISSN

1090-3038

Print_ISBN

0-87942-582-2

Type

conf

DOI

10.1109/VETEC.1991.140605

Filename

140605