Algorithms For Automatic And Robust Registration Of 3D Head Scans

Two methods for registering laser-scans of human heads and transforming them to a new semantically consistent topology defined by a user-provided template mesh are described. Both algorithms are stated within the Iterative Closest Point framework. The first method is based on finding landmark correspondences by iteratively registering the vicinity of a landmark with a re-weighted error function. Thin-plate spline interpolation is then used to deform the template mesh and finally the scan is resampled in the topology of the deformed template. The second algorithm employs a morphable shape model, which can be computed from a database of laser-scans using the first algorithm. It directly optimizes pose and shape of the morphable model. The use of the algorithm with PCA mixture models, where the shape is split up into regions each described by an individual subspace, is addressed. Mixture models require either blending or regularization strategies, both of which are described in detail. For both algorithms, strategies for filling in missing geometry for incomplete laser-scans are described. While an interpolation-based approach can Digital Peer Publishing Licence Any party may pass on this Work by electronic means and make it available for download under the terms and conditions of the current version of the Digital Peer Publishing Licence (DPPL). The text of the licence may be accessed and retrieved via Internet at http://www.dipp.nrw.de/. First presented at the Conference for Visual Media Prodction 2008, extended and revised for JVRB be used to fill in small or smooth regions, the modeldriven algorithm is capable of fitting a plausible complete head mesh to arbitrarily small geometry, which is known as “shape completion”. The importance of regularization in the case of extreme shape completion is shown.