Rain and Fog Recognition System Using Multiple in-Vehicle Sensors*

This paper describes a system for rain and fog recognition using multiple in-vehicle sensors. Fog density was calculated from both the preceding-vehicle images captured by an in-vehicle camera and the inter-vehicle distance measured by a millimeter-wave (mm-wave) radar. Rainfall determination is achieved by detecting raindrops on the windshield using images captured by the in-vehicle camera. Experiments using in-vehicle camera images and radar data collected while driving vehicles in foggy or rainy and fair conditions demonstrated the accuracy and the applicability of our system.