[Research on night visibility estimation method based on image features of dual light sources]

Haze, rain and snow bring a lot of inconvenience in our daily life, especially produce serious potential safety hazard for night transport. In the present paper the authors propose the vision-based dual light sources visibility method to estimate night visibility. This method is significantly advantaged with wide range, high precision and low cost, and has a good robustness in many kinds of weather conditions. Firstly, the authors give the basic visibility estimation model under the atmosphere multiple scattering theory. Secondly, the authors propose the dual light sources method to remove the luminance fluctuations of light sources and the atmosphere light effect, and formulize the algorithm to accurately gain information of light sources from the dual light sources image. At last, the authors design the dual light sources system and conduct a long time experiments under various atmosphere conditions. The experiments show that, with the baseline of 35 m, the visibility range is up to 15 000 m, and relative error is below 20%. This method and system can satisfy the demand of meteorological department and transport agency.