LAUSR

Driving on an expressway is dangerous on a foggy day due to drivers’ inability to obtain visibility information in time. In this research, a new daytime visibility-detection method based on pixel contrast implemented in a prewarning system is proposed. The new visibility-detection method considers various interference factors on low-visibility foggy days and is easy to implement. In addition, a new convenient and safe camera-calibration method is proposed. The prewarning system is based on the low-latency cellular vehicle-to-everything (C-V2X) communication technology; it enables drivers to obtain low-visibility information in real time. Our experiment results prove that the output visibility-distance information obtained from the proposed method is more stable, smooth, and robust than that of other methods. Currently, the proposed C-V2X application has been implemented on a real expressway, and its actual operation shows a high detection accuracy and stable performance.