Deterministic PointNetLK for Generalized Registration
There has been remarkable progress in the application of deep learning to 3D
point cloud registration in recent years. Despite their success, these
approaches tend to have poor generalization properties when attempting to align
unseen point clouds at test time. PointNetLK has proven the exception to this
rule by leveraging the intrinsic generalization properties of the Lucas &
Kanade (LK) image alignment algorithm to point cloud registration. The approach
relies heavily upon the estimation of a gradient through finite differentiation
-- a strategy that is inherently ill-conditioned and highly sensitive to the
step-size choice. To avoid these problems, we propose a deterministic
PointNetLK method that uses analytical gradients. We also develop several
strategies to improve large-volume point cloud processing. We compare our
approach to canonical PointNetLK and other state-of-the-art methods and
demonstrate how our approach provides accurate, reliable registration with high
fidelity. Extended experiments on noisy, sparse, and partial point clouds
depict the utility of our approach for many real-world scenarios. Further, the
decomposition of the Jacobian matrix affords the reuse of feature embeddings
for alternate warp functions.