Query2Uncertainty: Robust Uncertainty Quantification and Calibration for 3D Object Detection under Distribution Shift

TL;DR

This paper introduces Query2Uncertainty, a density-aware calibration method that improves uncertainty estimation and calibration for 3D object detectors under distribution shifts, enhancing safety in autonomous systems.

Contribution

It proposes a novel density-aware calibration approach that couples post-hoc calibrators with feature density estimation for better uncertainty quantification under distribution shifts.

Findings

Outperforms standard post-hoc calibration methods in in-distribution scenarios.

Effectively calibrates uncertainties under distribution shifts for 3D detectors.

Applicable to both camera-based and LiDAR-based 3D object detection.

Abstract

Reliable uncertainty estimation for 3D object detection is critical for deploying safe autonomous systems, yet modern detectors remain poorly calibrated, especially under distribution shifts. Although post-hoc calibration methods address this issue and provide improved calibration for in-distribution tests, they fail to adapt in distribution-shifted scenarios. In this work, we address this issue and introduce a density-aware calibration method that couples post-hoc calibrators with the feature density of latent object queries from DETR-style 3D object detectors. These queries form a compact, location and class-aware feature, ideal for density estimation, allowing our approach to adjust model confidences in distribution-shift scenarios. By fitting a density estimator on these query features, our approach jointly recalibrates both classification and bounding box regression uncertainties. On both a multi-view camera and LiDAR-based detector, our approach consistently outperforms standard post-hoc methods in both in-distribution and distribution-shifted scenarios. Code available https://tillbeemelmanns.github.io/query2uncertainty/ .