Use of a calibrated camera to study visibility in fog

摘要

When driving in foggy conditions, the impairment of vision may induce delay In the detection of obstacles and have negative impacts on traffic safety. In order to investigate the visibility thresholds of targets in these conditions, experiments were conducted in a fog chamber. As a first step, traditional photometers were used in order to monitor the luminance of the target and background in changing fog density. A new method using a calibrated camera was investigated in order to measure the complete visual field using a luminance matrix. The luminance map can subsequently be analysed in order to determine significant parameters for the visibility of the analysed objects. In addition to metrological aspects, the experiment data were analysed and compared to a theoretical approach using a Vision Model developed by Adrian. The visibility thresholds are discussed in relation to the experiment conditions.