Camera Pose, SLAM & Structure-from-Motion
Reducing Reliance on Pre-Built 3D Supervision for Training 3D-Aware Perception and Reconstruction Models
Generated automatically from the limitations stated in 24 papers (CVPR, ICCV, NeurIPS), listed under Evidence. It is not a paper, and it does not come from papers submitted to CSPaper.
The problem
Nearly every system that connects 2D images to 3D representations — whether for localization, reconstruction, or generation — is trained against 3D artifacts that must be manufactured in advance: dense depth, camera poses, meshes, point clouds, scene graphs, or splat reconstructions from dense multi-view rigs. This makes training data a bottleneck that caps scalability to ordinary single-view RGB collections, blocks application to domains without depth sensors or calibrated rigs, and drives enormous compute costs for pseudo-ground-truth generation. Until models can learn the 2D-to-3D link without manufactured 3D supervision, the field's coverage is limited to the small slice of the visual world that has been 3D-digitized.
Why it matters
Training 3D-aware models directly on uncalibrated single-view image and video collections at scale, removing dependence on depth sensors, calibration rigs, and offline 3D reconstruction of training scenes.
Ways to approach it
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- 1
Systematic ablation of 3D supervision across a fixed backbone: take one representative 2D-to-3D architecture and retrain it with progressively weaker supervision — full GT 3D, pseudo-GT from off-the-shelf depth/pose estimators, self-supervised multi-view consistency losses only, and single-view-only — measuring task accuracy, generalization to unseen domains, and total training compute. This quantifies which parts of the 3D stack are actually load-bearing and which are trainable artifacts. Measured: accuracy-vs-supervision curves and data-sourcing cost.
- 2
Pseudo-3D label generation at web scale: build a pipeline that converts uncalibrated internet video into weak 3D supervision (relative poses, sparse depth, covisibility) using self-supervised pose estimators and monocular depth, with confidence filtering, and measure the tradeoff between pseudo-label volume/quality and downstream performance. Measured: downstream task accuracy as a function of pseudo-label noise and scale.
- 3
Supervision-free 2D-3D consistency objectives: train with losses that enforce geometric consistency (epipolar constraints, cross-view photometric agreement, cycle-consistency between 2D observations and predicted 3D structure) without any explicit 3D labels, and benchmark against supervised counterparts on standard localization and reconstruction metrics. Measured: gap to fully-supervised baselines.
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Why it might fail
The ablations may show that high-quality 3D ground truth is genuinely load-bearing, with consistency-only training collapsing to degenerate solutions, meaning the barrier is fundamental rather than a data-manufacturing problem.
Sub-problems
Learning Feed-Forward 3D Gaussian Splatting from Unposed 2D Image and Video Collections
Current feed-forward 3D Gaussian Splatting and novel view synthesis architectures require calibrated multi-view captures, RGB-D inputs, or pre-optimized 3D target ground truths during training. This creates a hard barrier against training on internet-scale passive 2D video and uncalibrated image collections. Consequently, models remain confined to small synthetic or specialized multi-camera lab datasets, suffering severe generalization collapse when applied to arbitrary single-view or in-the-wild camera trajectories.
Evidence
Each paper's own statement of the limitation, verbatim.
- VideoWeaver: Multimodal Multi-View Video-to-Video Transfer for Embodied AgentsCVPR 2026
Natively generates only 3 views; additional views require autoregressive conditioning rather than joint generation, and multi-view training is limited to ~75K videos with Bridge excluded (low-resolution multi-view)
- SG2Loc: Sequential Visual Localization on 3D Scene GraphsICML 2026
Relies on the availability of pre-constructed 3D scene graphs with object-level segmented meshes and pre-trained multi-modal embeddings.
- RayI2P: Learning Rays for Image-to-Point Cloud RegistrationICLR 2026
Requires overlapping field of view between the 2D image and the 3D point cloud, relying on an overlap detector to mask non-visible points.
- Learning Physics-Grounded 4D Dynamics with Neural Gaussian Force FieldsICLR 2026
Requires multi-view RGB captures for feed-forward 3D Gaussian initialization, failing when only single-view or sparse observations are available.
- Learning 3D-Gaussian Simulators from RGB VideosICML 2026
Requires multi-view RGB video with known camera poses (or monocular depth priors) rather than learning purely from arbitrary single-view passive video.
- Hg-I2P: Bridging Modalities for Generalizable Image-to-Point-Cloud Registration via Heterogeneous GraphsCVPR 2026
Requires high overlap between 2D images and 3D submaps to function effectively.
- CHROMA: Consistent Harmonization of Multi-View Appearance via Bilateral Grid PredictionICLR 2026
Requires a separate multi-view pre-training phase involving a large pre-trained 3D foundation model before downstream reconstruction.
- Styl3R: Instant 3D Stylized Reconstruction for Arbitrary Scenes and StylesNeurIPS 2025
Limited scalability to large scenes due to VRAM/memory constraints; training is data-hungry and required 8 A100 GPUs for ~1.5 days; 2-view-trained models produce duplicated Gaussians with 8 input views
Show all 24 papers
- Splat-based 3D Scene Reconstruction with Extreme Motion-blurICCV 2025
Requires high-quality depth maps with minimal outliers, necessitating pre-processing steps like depth erosion.
- SCFlow2: Plug-and-Play Object Pose Refiner with Shape-Constraint Scene FlowCVPR 2025
Requires a 3D mesh/shape prior of the target object at inference time.
- Do It Yourself: Learning Semantic Correspondence from Pseudo-LabelsICCV 2025
Still requires per-category masks and 3D pose annotations, so further scaling depends on their availability; a feasibility analysis for removing this dependence is only preliminary
- Alligat0R: Pre-Training through Covisibility Segmentation for Relative Camera Pose RegressionNeurIPS 2025
Requires depth maps and camera poses (or automated pseudo-ground-truth from registered video plus monocular depth, which is computationally intensive) to generate dense covisibility annotations, limiting scalability to domains without 3D data
- ACE-G: Improving Generalization of Scene Coordinate Regression Through Query Pre-TrainingICCV 2025
Requires computationally heavy pre-training across ~120,000 mapping-query splits with ground-truth 3D data (4.4M iterations on 8 A100 GPUs).
- Revisit Self-supervision with Local Structure-from-MotionECCV 2024
Requires calibrated cameras and relatively dense, confident correspondence maps (PDC-Net confidence threshold 0.95 filters sequences), limiting applicability to wild uncalibrated or low-texture footage
- PLGSLAM: Progressive Neural Scene Represenation with Local to Global Bundle AdjustmentCVPR 2024
Requires RGB-D input with known camera intrinsics and depth-based SDF supervision; not applicable to monocular-only settings.
- GSD: View-Guided Gaussian Splatting Diffusion for 3D ReconstructionECCV 2024
Requires pre-optimized 3D Gaussian Splatting ground-truth data from dense multi-view captures for training, limiting scaling to standard uncalibrated 2D image datasets.
- DiffuScene: Denoising Diffusion Models for Generative Indoor Scene SynthesisCVPR 2024
Requires fully labeled 3D scenes for training; 2D-labeled data is not exploited
- SE(3) Diffusion Model-based Point Cloud Registration for Robust 6D Object Pose EstimationNeurIPS 2023
Requires depth maps with known camera intrinsics and a complete mesh model for the model point cloud; inference time grows with reverse steps (0.04–0.17 s for 1–5 steps)
- LDL: Line Distance Functions for Panoramic LocalizationICCV 2023
Requires a pre-built 3D map with line segments and SuperPoint descriptors (built offline from a colored point cloud via synthetic rendering), plus reliance on principal-direction structure in man-made scenes.
- SGAM: Building a Virtual 3D World through Simultaneous Generation and MappingNeurIPS 2022
Requires RGB-D data for training and as initial input, precluding its use on purely RGB datasets.
- Coupled Iterative Refinement for 6D Multi-Object Pose EstimationCVPR 2022
Requires high-quality 3D mesh models and camera intrinsic parameters to be known a priori.
- SGPA: Structure-Guided Prior Adaptation for Category-Level 6D Object Pose EstimationICCV 2021
Requires high-quality categorical 3D point cloud priors for each supported object class
- Robust Neural Routing Through Space Partitions for Camera Relocalization in Dynamic Indoor EnvironmentsCVPR 2021
Requires RGB-D input for both training and inference, limiting applicability to sensors with depth-sensing capabilities.
- Learning Camera Localization via Dense Scene MatchingCVPR 2021
Requires reference database images to have pre-computed, dense 3D scene coordinate maps from depth sensors or multi-view stereo reconstruction.
Nearest existing work
- MASt3R-SLAM: Real-Time Dense SLAM with 3D Reconstruction PriorsCVPR 2025
- CanonPose: Self-Supervised Monocular 3D Human Pose Estimation in the WildCVPR 2021
- No Pose at All: Self-Supervised Pose-Free 3D Gaussian Splatting from Sparse ViewsICCV 2025
- Reloc3r: Large-Scale Training of Relative Camera Pose Regression for Generalizable, Fast, and Accurate Visual LocalizationCVPR 2025
- UnsupervisedR&R: Unsupervised Point Cloud Registration via Differentiable RenderingCVPR 2021
- From None to All: Self-Supervised 3D Reconstruction via Novel View SynthesisCVPR 2026
- A Constrained Optimization Approach for Gaussian Splatting from Coarsely-posed Images and Noisy Lidar Point CloudsICCV 2025
- SparsePose: Sparse-View Camera Pose Regression and RefinementCVPR 2023
- A Real World Dataset for Multi-View 3D ReconstructionECCV 2022
- NopeRoomGS: Indoor 3D Gaussian Splatting Optimization without Camera Pose InputNeurIPS 2025
- Accelerated Coordinate Encoding: Learning to Relocalize in Minutes Using RGB and PosesCVPR 2023
- Pseudo Flow Consistency for Self-Supervised 6D Object Pose EstimationICCV 2023
- ProDyG: Progressive Dynamic Scene Reconstruction via Gaussian Splatting from Monocular VideosNeurIPS 2025
- Splat-based 3D Scene Reconstruction with Extreme Motion-blurICCV 2025
- LongSplat: Robust Unposed 3D Gaussian Splatting for Casual Long VideosICCV 2025