Cameras and zoom lenses from Rainbow are being used at freeway and intersection controls throughout the United States by Florida-based Control Technologies.
The installer has chosen a modified version of Rainbow’s one third inch black and white 580 TV lines camera.
Based on data from the cameras, civic authorities are able to calibrate the cycle of signalised intersections and where necessary speed up vehicle exits from congested stretches of freeway. The aim is to ease movement on freeways and minimise congestion at known bottlenecks. The scene analysis approach used by Control Technologies is superior, it is claimed, to simple magnetic sensors and the techniques are being employed in states including Texas, Florida, Georgia, Virginia, Washington DC and New York.
Images are fed to a video processor which may evaluate a traffic scene through pixel analysis, or the scene of free-flowing traffic might be assessed by the processor according to factors such as speed, volume on individual lanes or ‘headway time’, this being the gap between one vehicle and the next. The system can also use five classifications when distinguishing between vehicles by length.
The Rainbow cameras are mounted on freeway gantries, luminaires and mast arms. They are being used in conjunction with Rainbow‚s 6.5~65mm F1.4 auto-iris zoom lenses.
