Stereovision for the determination of fireline intensity in vegetation fire

Abstract

Fireline intensity is one of the most relevant quantities in forest fire science. It helps to evaluate the effects of fuel treatment on fire behaviour, to establish limits for prescribed burning. It is also used as a quantitative basis to support fire suppression activities. However, its measurement at field scale for actual fire remains a challenge. Hence, it has been poorly used as a key quantity to test the new generation of models of fire spread that have been developed these last ten years. An inverse method to obtain fireline intensity is through the observation of the flame length. This geometrical information is measured using a stereovision system placed in the lateral position relative to the direction of the fire spread. Algorithms were developed in order to automatically segment the fire area of the images and estimate the 3D coordinates of salient fire points and then the flame length. The three dimensions of the information permit to obtain the flame length with metric measures. In the present work, we directly measure the fireline intensity at laboratory scale by oxygen consumption calorimetry. The results are then used to establish a relationship between fireline intensity and flame length obtained by the stereovision system. © 2011 WIT Press.