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UniDepth: Universal Monocular Metric Depth Estimation
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Proposes UniDepth, a universal monocular metric depth estimator that predicts metric 3D points from a single image without camera intrinsics, using a self-prompted dense camera module, a pseudo-spherical output space, and a geometric invariance loss.
Problem
Monocular metric depth estimation methods overfit to their training domains and camera intrinsics, failing to generalize zero-shot to unseen domains and arbitrary cameras without external camera information.
Approach
Predict a dense camera representation (azimuth and elevation per pixel) from the image itself to prompt the depth module via cross-attention, output 3D points in a pseudo-spherical space (θ, ϕ, log-depth) that disentangles camera and depth, and enforce consistency of camera-conditioned depth features across geometric augmentations.
Key results
- In zero-shot evaluation on ten datasets, UniDepth-V reaches 98.4 δ1 on NYU and 93.4 δ0.5 / 98.6 δ1 on KITTI Eigen-split, ranking first on the official KITTI Depth Prediction Benchmark at submission time.
- UniDepth achieves an average 34.0% improvement in SIlog over prior SotA methods across zero-shot test sets, with UniDepth-V outperforming in-domain trained methods on NYU and KITTI.
- Ablations show that removing the pseudo-spherical representation (Cartesian output) drops out-of-domain δ1 from 57.06 to 37.09, and removing stop-gradient on the camera module drops out-of-domain δ1 to 46.60.
Measured effects reported in the paper
| What was changed | Where | Measured | Effect |
|---|---|---|---|
| use UniDepth-V instead of ZoeDepth | UniDepth-V · NYU test set | δ1: 95.2 -> 98.4 | Helped |
| use UniDepth-V instead of NeWCRF | UniDepth-V · KITTI Eigen-split test set | δ1: 97.5 -> 98.6 | Helped |
| add the camera module (ablation) | Full UniDepth · Out-of-Domain | δ1: 48.38±0.97 -> 57.06±1.48 | Helped |
| use pseudo-spherical rather than Cartesian output (ablation) | Full UniDepth · Out-of-Domain | δ1: 37.09±1.37 -> 57.06±1.48 | Helped |
| add geometric invariance loss (ablation) | Full UniDepth · Out-of-Domain | δ1: 52.89±0.21 -> 57.06±1.48 | Helped |
| use dense instead of sparse camera prompting (ablation) | Full UniDepth · Out-of-Domain | δ1: 55.65±0.18 -> 57.06±1.48 | Helped |
| stop gradients from the camera module to the encoder (ablation) | Full UniDepth · Out-of-Domain | δ1: 46.60±0.25 -> 57.06±1.48 | Helped |
| add camera module and use Cartesian 3D output (ablation) | Full UniDepth · Out-of-Domain | δ1: 48.19±1.02 -> 57.06±1.48 | Helped |
| add camera module to the pseudo-spherical baseline (ablation) | Full UniDepth · Out-of-Domain | δ1: 51.22±0.35 -> 57.06±1.48 | Helped |
Surprising findings
- Predicting camera with a bootstrapped self-prompt can outperform models given ground-truth camera intrinsics on some datasets such as ETH3D and IBims-1 in SIlog.
- Zero-shot UniDepth surpasses methods trained directly on NYU and KITTI in δ1 on those benchmarks.
Limitations
- Scale-dependent metrics degrade on some out-of-domain sets such as ETH3D and IBims-1 (FA drops of 11.8% and 31.4%), suggesting need for domain-specific fine-tuning.
- Bootstrapped camera prediction adds noise to scaled depth on out-of-domain camera types such as ETH3D and HAMMER, worsening δ1.
- Training requires roughly 12 days on 8 NVIDIA A100 GPUs.
Experimental setup
Datasets: Argoverse2 Waymo DrivingStereo Cityscapes BDD100K Mapillary-PSD A2D2 ScanNet Taskonomy SUN-RGBD Diode Indoor IBims-1
Benchmarks: SUN-RGBD Diode Indoor IBims-1 VOID HAMMER ETH-3D nuScenes DDAD NYU-Depth V2 KITTI Eigen-split
Metrics: δ1 SIlog F-score A.Rel RMS RMSlog Chamfer Distance δ0.5 ARelC
Baselines: BTS AdaBins NeWCRF iDisc ZoeDepth Metric3D ZeroDepth
Builds on: ViT ConvNext DINOv2
Closest papers by meaning
- UniK3D: Universal Camera Monocular 3D Estimation (CVPR 2025 · similarity 0.91)
- Metric from Human: Zero-shot Monocular Metric Depth Estimation via Test-time Adaptation (NeurIPS 2024 · similarity 0.91)
- SharpDepth: Sharpening Metric Depth Predictions Using Diffusion Distillation (CVPR 2025 · similarity 0.90)
- A Simple yet Universal Framework for Depth Completion (NeurIPS 2024 · similarity 0.89)
- DepthMaster: Unified Monocular Depth Estimation for Perspective and Panoramic Images (NeurIPS 2026 · similarity 0.89)
- GeoDepth: From Point-to-Depth to Plane-to-Depth Modeling for Self-Supervised Monocular Depth Estimation (CVPR 2025 · similarity 0.88)
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