High resolution trichromatic road surface scanning with a line scan camera and light emitting diode lighting for road-kill detection

Abstract

This paper presents a road surface scanning system that operates with a trichromatic line scan camera with light emitting diode (LED) lighting achieving road surface resolution under a millimeter. It was part of a project named Roadkills-Intelligent systems for surveying mortality of amphibians in Portuguese roads, sponsored by the Portuguese Science and Technology Foundation. A trailer was developed in order to accommodate the complete system with standalone power generation, computer image capture and recording, controlled lighting to operate day or night without disturbance, incremental encoder with 5000 pulses per revolution attached to one of the trailer wheels, under a meter Global Positioning System (GPS) localization, easy to utilize with any vehicle with a trailer towing system and focused on a complete low cost solution. The paper describes the system architecture of the developed prototype, its calibration procedure, the performed experimentation and some obtained results, along with a discussion and comparison with existing systems. Sustained operating trailer speeds of up to 30 km/h are achievable without loss of quality at 4096 pixels' image width (1 m width of road surface) with 250 µm/pixel resolution. Higher scanning speeds can be achieved by lowering the image resolution (120 km/h with 1 mm/pixel). Computer vision algorithms are under development to operate on the captured images in order to automatically detect road-kills of amphibians.This work was financed by FEDER Funds, through the Operational Programme for Competitiveness Factors-COMPETE, and by National Funds through FCT-Foundation for Science and Technology of Portugal, under the project PTDC/BIA-BIC/4296/2012 with the name-Roadkills: Intelligent systems for mapping amphibian mortality on Portuguese roads. C.S. and M.F. are supported by Research Grants contracts by FCT (UMINHO/BI/172/2013 and UMINHO/BI/175/2013 respectively). N.S. is supported by an IF (Investigador FCT) contract by FCT (IF/01526/2013). The authors also wish to thank the entities involved, in particular, School of Engineering of the University of Minho and the Algoritmi research center, the Faculty of Sciences of the University of Porto and the University Institute of Maia.info:eu-repo/semantics/publishedVersio