US Patent 9503696 Visual detection of volcanic plumes

A system for detecting volcanic plumes using a camera on an aircraft, a distant point-like source of light, and a computerized method of processing images acquired by the camera to detect phenomena indicative of the presence of volcanic plumes in a volume of space intersected by light from the light source. A computer system is programmed to determine whether the image data from the camera has characteristics indicating that the imaged light had passed through a volcanic plume or not. In response to detection of a volcanic plume in the flight path of an aircraft, the computer system outputs an alert activation signal to an alert device that produces a visible or audible alert.