Affiliations: [a] Integration Engineering Laboratory, Department of Mechanical and Aeronautical Engineering, University of California, Davis, CA 95616, USA. Tel.: +1 530 752 5020; Fax: +1 530 752 4158; E-mail: hhcheng@ucdavis.edu | [b] Office of New Technology and Research, California Department of Transportation, Box 942873, MS 83, Sacramento, CA 94273, USA
Correspondence:
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Corresponding author.
Abstract: A three layer real-time architecture for a highway vehicle detection system is presented in the article. The Laser-Based Detection System (LBDS), focused on helping the Intelligent Transportation System (ITS), measures a key quantitative parameter of vehicles moving across a link of highway, namely, travel time. Travel time is based upon identifying and re-identifying vehicles at various points on the highway. This article provides a method to collect hard real-time signals from an active laser source in the LBDS and calculate real-time vehicle parameters using a standard computer. A method of seamlessness message exchange between a hard real-time kernel process, for real-time data acquisition, and a soft real-time application process, for computing and displaying, is given under the RTLinux environment. Experimental results from field tests show that the application of the real-time architecture to the LBDS provides vehicle parameter calculations deterministically. Experimental data are analyzed using the Video Sync program with both video images and graphical display.
