Analysis of Thermal Video for Coarse to Fine Particle Tracking in Volcanic Explosion Plumes

International audienceThis paper presents two algorithms of feature extraction and 10 segmentation. The first algorithm is applied to detect tens of thousands of targets moving at high velocities (100's m/s) and with different sizes, velocities, shapes and directions. Upon detection, we compute statistics for each of these parameters for each particle, without any assumption nor a priori information. The second algorithm was developed to detect a 15 slow moving convective cloud. The challenge was to follow the evolution of the contours of a heterogeneous element in front of a homogeneous but possibly moving background. These algorithms were applied on images acquired with thermal cameras with different settings (frame rate, frame size, focal length, instantaneous field of view). A case study concern-20 ing images of volcanic explosive events is finally presented. Volcanoes provide, during an eruption, a source of both ballistic ejecta and a con-vective plume of finer particles, gas and entrained air both of which can be imaged in the infrared wavelength. : Results