VGGT's own confidence missed its pose failures at 79.7 percent, but a probe on its features reached 93.5 percent
AspireAI community · arXiv
Feed-forward 3D reconstruction models such as VGGT regress cameras and geometry in a single forward pass but report no uncertainty for the poses they predict, so an incorrect relative pose looks no different from a correct one. On HardMatch, a new benchmark of 1,000 deliberately difficult image pairs where VGGT fails on 35 percent, a linear probe on VGGT's frozen features predicted pose failure on held-out categories at 93.5 percent ROC-AUC, against 79.7 percent for VGGT's own point-map confidence and 77.7 percent for a classifier trained on all of VGGT's outputs. The probe catches failures the model is confident about, lets a downstream system abstain, and transferred without retraining to rotation failures on PhotoTourism and ScanNet-1500 beyond what co-visibility explains. The knowledge is not in the per-image encoder but partway through the layers that fuse the two views, and the same held for a second model, and the paper does not report end-task reconstruction gains from using the probe.
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