Line Marking Retroreflectivity
Impulse geophysics has developed a technique based on night-time digital video to obtain the retroreflectivity of line markings. The value of retroreflectivity determines the visibility of the line markings at night. Our research programme has produce algorithms to convert grey-scale intensity to Retroreflectivity Luminance (mcd.m-2.lx-1)
The system operates at traffic speed and the lines are illuminated by a high intensity LED source. The receiving CCDs are calibrated to reproduce comparable grey-scale outputs. The system collects left and right edge line marking retroreflectivity simultaneously from the digital video. The same digital video can be used to test Road Stud Retroreflectivity and Road Sign Retroreflectivity. Analysis is automated and outputs are a measurement of retroreflectivity average over 2 meters in Geo-Referenced form.
These results can be statistically analysed along with street lighting information to produce green, amber and red traffic light style output to highlight the areas requiring improvement. Outputs are in CSV, Mapinfo Tables or Shapefiles.