A 3D foundation model that says how much to trust the poses it predicts.
Problem. Feed-forward 3D foundation models made reconstruction fast and
robust, but they answer with a single estimate and no measure of confidence.
Downstream systems such as sensor fusion, active vision, and robotics need to
know how far to trust each pose, not only what the pose is.
Idea. Keep VGGT’s backbone and pose prediction frozen, and train a second
lightweight branch to predict a full 6×6 covariance for each camera
pose, formulated on SE(3). The branch uses body-centric
perturbations on the Lie algebra, a left-invariant metric that reconciles
meters with radians, and a negative log-likelihood with a curriculum that
prevents the covariances from collapsing.
Why it matters. On CO3D the predicted uncertainty ranks frames by their
pose error and its structure matches the analytical covariance of classical
bundle adjustment; the fitted temperature is 1.01, so the head is already
calibrated on typical frames. On EPIC-KITCHENS it reports that a dynamic
reconstruction is unreliable as a whole, though it does not single out the
individual frames that are misplaced. This turns an otherwise deterministic
reconstructor into a component that can be used in probabilistic pipelines,
without modifying its frozen pose predictor.
Sole author, BSc thesis. Supervised by Prof. Alessandro Pigati, Bocconi University.