“…Traditional point cloud registration algorithms (e.g., [8,1,50,33,46,46]) have been comprehensively reviewed in [56]. Recently, learningbased algorithms have been proposed to replace the individual components in the classical registration pipeline, including keypoint detection [4,40,34] and feature description [21,22,23,55,4,18,28,32,2]. Besides, end-toend registration networks [3,67,68,76] have been proposed.…”