Point Set Registration with Integrated Scale Estimation

We present an iterative registration algorithm for aligning two differently scaled 3-D point sets. It extends the popular Iterative Closest Point (ICP) algorithm by estimating a scale factor between the two point sets in every iteration. The presented algorithm is especially useful for the registration of point sets generated by structure-frommotion algorithms, which only reconstruct the 3-D structure of a scene up to scale. Like the original ICP algorithm, the presented algorithm requires a rough pre-alignment of the point sets. In order to determine the necessary accuracy of the pre-alignment, we have experimentally evaluated the basin of convergence of the algorithm with respect to the initial rotation, translation, and scale factor between the two point sets.