We describe a variation of the iterative closest point (ICP) algorithm for aligning two point sets under a set of transformations. Our algorithm is superior to previous algorithms because (1) in determining the optimal alignment, it identifies and discards likely outliers in a statistically robust manner, and (2) it is guaranteed to converge to a locally optimal solution. To this end, we formalize a new distance measure, fractional root mean squared distance (frmsd), which incorporates the fraction of inliers into the distance function. We lay out a specific implementation, but our framework can easily incorporate most techniques and heuristics from modern registration algorithms. We experimentally validate our algorithm against previous techniques on 2 and 3 dimensional data exposed to a variety of outlier types.
@article{arxiv.cs/0606098,
title = {Outlier Robust ICP for Minimizing Fractional RMSD},
author = {Jeff M. Phillips and Ran Liu and Carlo Tomasi},
journal= {arXiv preprint arXiv:cs/0606098},
year = {2009}
}