Metrological Tool for the Characterization of Flame Fronts Based on the Coupling of a Heat Flux Approach with Image Processing Data

The aim of this paper is to present some improvements in the metrology of forest fire flames by coupling image processing and radiative heat flux measurement. A new metrological tool using a visual video camera and a specific multiple thermal sensor is proposed. By means of an appropriate segmentation algorithm and the Direct Linear Transformation, the image processing methodology gives the forward or the backward fire front positions as input data to a radiative heat flux approach. Using a simplified flame model, this technique provides fire front positions versus time, and average values for the flame length, flame depth, flame tilt angle, apparent flame temperature and flame emissivity. The rates of spread, obtained by a linear regression of the determined fire front positions, as well as the thermal and radiative properties of the flame, are compared favorably to those given in the literature.