Appearance-based automatic target recognition in overhead LADAR range imagery

This paper presents an algorithm for automatic target recognition in, overhead LADAR range imagery using "appearance-based" models. The detection is accomplished using a two stage Hough transform where the target is modelled as a small set of boundary pixels with associated local properties. The first stage Hough transform keeps tracks of all the edge points matched by the model points. The second stage Hough transform then efficiently identifies the candidate space by incrementing the accumulator array along precomputed (for each model point) swaths. A robust estimator, the MAD, is then used to do the template matching directly on the second stage solutions which are already very accurate. Finally, we illustrate our algorithm on some real LADAR images and discuss the error rates.