This paper presents a new instrumentation system, based on stereovision, for the visualization and quantitative characterization of fire fronts in outdoor conditions. The system consists of a visible pre-calibrated stereo camera and a computer with dedicated software. In the proposed approach, images are captured simultaneously and processed using specialized algorithms. These algorithms permit to model 3D fire fronts and extract geometric characteristics like volume, surface area, heading direction and length. Experiments were carried out in outdoor scenarios and the obtained results show the efficiency of the proposed system. This system successfully measures 3D geometric parameters of fire fronts over a range of combustible and environmental conditions.