Relationship between visibility and the contrast evaluation index determined by live camera image processing

Abstract

We have obtained visibility ranges calculated by a device to measure both visibility (VIS_LPM) and visually determined ranges from live camera images (VIS_camera) for Senjugahara, Tateyama-machi, Toyama Prefecture, during the winter of 2021. We developed an estimation formula for the visibility range based on the relationship between WIPS_A and a new contrast evaluation index calculated using only live camera images, without using any camera specification information (CCD size, lens focal length, etc.). The visibility estimation equation was validated by calculating the perfect percent correct, percent correct, miss rate, false alarm ratio, and threat score using a 5×5 contingency table based on data from the winter season of 2022. This was considered to have the same level of practicality as the JMA's forecast of precipitation availability. The number of live cameras has been increasing in recent years, and this study shows that the visibility estimation method is sufficiently effective for determining a wide-area range of visibility.