Schwarzinger et al. 1992 : The authors have developed a vision system for automatic car following and object classification. The CARTRACK system can reliably detect, track, and identify the back of an automobile in a dynamic image taken from a following car in the same lane or in a neighbor lane. The detection and tracking system exploits the symmetry property of the rear view of normal cars. The class of objects that are detected by CARTRACK includes normal cars of all sizes as well as trucks and conventional trailers. Parallel to the tracking process, a model-based identification module identifies the type of vehicle being followed. For objects of known size, it also facilitates distance estimation. Deformable 2D models (planar feature graphs) constructed from various visual features are used. The image features in a region of interest selected by the symmetry-based detection process are matched with the model objects by means of an elastic net technique.