Sonata: Self-Supervised Learning of Reliable Point Representations
Authors: name: Xiaoyang Wu, name: Daniel DeTone, name: Duncan Frost, name: Tianwei Shen, name: Chris Xie, name: Nan Yang, name: Jakob Engel, name: Richard Newcombe, name: Hengshuang Zhao, name: Julian Straub
Organization: Pointcept

In this paper, we question whether we have a reliable self-supervised point
cloud model that can be used for diverse 3D tasks via simple linear probing,
even with limited data and minimal computation. We find that existing 3D
self-supervised learning approaches fall short when evaluated on representation
quality through linear probing. We hypothesize that this is due to what we term
the "geometric shortcut", which causes representations to collapse to low-level
spatial features. This challenge is unique to 3D and arises from the sparse
nature of point cloud data. We address it through two key strategies: obscuring
spatial information and enhancing the reliance on input features, ultimately
composing a Sonata of 140k point clouds through self-distillation. Sonata is
simple and intuitive, yet its learned representations are strong and reliable:
zero-shot visualizations demonstrate semantic grouping, alongside strong
spatial reasoning through nearest-neighbor relationships. Sonata demonstrates
exceptional parameter and data efficiency, tripling linear probing accuracy
(from 21.8% to 72.5%) on ScanNet and nearly doubling performance with only 1%
of the data compared to previous approaches. Full fine-tuning further advances
SOTA across both 3D indoor and outdoor perception tasks.