In situ cloud detection by webcam

Images from a webcam installed by OMP at PDM are used to detect in situ cloudy conditions at the Pic du Midi.

The image processing algorithm is based on edge detection using a Canny filter on several areas of the image. Areas with sharp contours will be considered free of cloud, while blurred contours will be considered as the signature of fog. These various information are then merged using a fuzzy logic algorithm in order to obtain a boolean information valid for the whole station.

Depending on the visibility of these areas, the algorithm will thus return 0 (false) corresponding to the absence of fog, or 1 (true) for a presence of fog, whatever its density.

No value is returned for night periods.