A key component of Visual Simultaneous Localization and Mapping (VSLAM) is estimating relative camera poses using matched keypoints. Accurate estimation is challenged by noisy correspondences. Classical methods rely on stochastic hypothesis sampling and iterative estimation, while learning-based methods often lack explicit geometric structure. In this work, we reformulate relative pose estimation as a relational inference problem over epipolar correspondence graphs, where matched keypoints are nodes and nearby ones are connected by edges. Graph operations such as pruning, message passing, and pooling estimate a quaternion rotation, translation vector, and the Essential Matrix (EM). Minimizing a loss comprising (i) L2 differences with ground truth (GT), (ii) Frobenius norm between estimated and GT EMs, (iii) singular value differences, (iv) heading angle differences, and (v) scale differences, yields the relative pose between image pairs. The dense detector-free method LoFTR is used for matching. Experiments on indoor and outdoor benchmarks show improved robustness to dense noise and large baseline variation compared to classical and learning-guided approaches, highlighting the effectiveness of global relational consensus.
Figures & tables
Figure 1: General Architecture of Visual SLAM Pipeline - Highlights Visual Odometry (Tracking) module Carlone et al. (2025) .
Figure 2: Epipolar Graph VO Block Diagram - Includes Graph Construction to Relative Pose Regression
Figure 3: GNN Model Architectural Block Diagram - Accepts input graphs and output being Regressed Pose further used in calculation of EM
Frame Sep
NetVlad Sim. (%)
Epipolar Set
Epipolar Ratio
1
85
5827
0.89
5
71.7
864
0.13
10
50.5
561
0.09
15
36.3
349
0.05
20
22.2
428
0.07
25
15.1
384
0.06
Table 1: LoFTR Statistics for different frame separations (Matched Set N=6000 )
Frame Sep
ETH3D
KC
TA
Sim (%)
Closures
Sim (%)
Closures
Sim (%)
Closures
0
70.52
1
72.27
3
71.60
1
5
50.38
2
78.81
6
31.97
1
10
50.59
2
79.92
9
33.64
1
15
52.91
2
81.67
15
34.15
1
20
56.55
3
81.95
20
34.79
1
Table 2: NetVLAD Similarity and Loop Closures across ETH3D, KC, and TA datsets.
Model
Preprocessing
Output
PoseNet
5.0
10.0
RPNet
5.0
12.0
RPNet+
5.0
12.5
DiffPoseNet
5.0
15.5
GAT + 2xGCN (ours)
10.0
2.0
3xGCN + GAT (ours)
10.0
2.5
Table 3: Runtime comparison, in seconds, on KITTI dataset using Tesla T4 GPU (batch size = 16).
Figure 4: Variation in DTE and DRE across architectures for the first 10 samples of the ETH3D Botanical Garden test dataset.
Figure 5: Variation in DTE and DRE across architectures for the first 10 samples of KITTI Sequence 01 (The legend is the same as in Fig. 4 ).
Metric
PoseNet
RPNet
RPNet+
DiffPoseNet
GAT+2xGCN
3xGCN+GAT
GIN_SumPool
CrossGraph
ATE (m)
21.065
17.571
12.108
36.714
9.621
10.027
9.864
13.164
APE (m)
16.478
15.917
11.380
33.651
7.740
7.402
8.312
10.258
DTE (deg)
12.350
15.194
10.439
18.956
5.645
4.027
5.102
9.071
DRE (deg)
0.0280
0.0290
0.0250
0.0280
0.0270
0.0220
0.0190
0.030
Table 4: TA dataset (tartan_left).
Seq 02
Metric
PoseNet
RPNet
RPNet+
DiffPoseNet
GAT+2xGCN
3xGCN+GAT
GIN_SumPool
CrossGraph
ATE (m)
35.786
45.123
53.460
28.198
25.631
29.552
23.276
22.198
APE (m)
30.727
38.598
45.887
23.732
19.011
23.276
20.521
18.732
DTE (deg)
25.858
25.828
24.907
20.939
23.733
24.997
19.561
18.939
DRE (deg)
49.665
88.968
92.330
137.472
48.489
50.192
48.830
43.472
Seq 03
Table 5: KC dataset.
Botanical Garden
Metric
PoseNet
RPNet
RPNet+
DiffPoseNet
GAT+2xGCN
3xGCN+GAT
GIN_SumPool
CrossGraph
ATE (m)
2.116
2.012
1.829
2.560
1.877
1.820
1.980
1.818
APE (m)
2.024
1.996
1.645
2.299
1.809
1.619
1.881
1.606
DTE (deg)
4.093
2.599
3.171
2.787
2.911
3.155
2.863
3.659
DRE (deg)
70.129
84.264
88.262
92.868
52.373
84.983
83.037
95.402
Boulders
Table 6: ETH3D datasets.
Seq 01
Metric
PoseNet
RPNet
RPNet+
DiffPoseNet (c)
GAT+2xGCN
3xGCN+GAT
GIN_SumPool
CrossGraph
ATE (m)
1.538
1.435
1.927
1.392
3.246
0.390
1.871
3.499
APE (m)
1.467
1.375
1.754
1.343
2.640
0.296
1.656
3.142
DTE (deg)
0.030
0.023
0.035
0.026
0.062
0.025
0.023
0.098
DRE (deg)
1.708
122.310
0.894
9.967
1.263
0.201
1.652
126.010
Seq 05
Table 7: KITTI sequences 01, 05, and 09 with consecutive frames.
Estimating relative pose from image pairs fundamentally requires only a minimal subset of geometrically consistent correspondences. However, most learning-based approaches rely on dense matching or direct regression, leading to redundancy and reduced geometric interpretability. In this work, we propose a sparse epipolar matching framework that predicts a compact set of correspondences optimized for geometric consistency across varying temporal baselines. To address residual noise and misalignment, we introduce an epipolar diffusion process that models correspondence uncertainty and refines keypoints toward epipolar consistency. The refined correspondences, along with depth cues, are lifted into a graph representation forming a Steiner graph that encodes relational structure between points. A graph neural network learns a compact subset of informative correspondences, which are passed to a differentiable singular value decomposition solver for end-to-end geometric estimation. Relative pose is recovered from the resulting essential matrix and evaluated in a visual odometry setting on the TartanAir and KITTI SLAM datasets. Experimental results demonstrate that combining sparse matching, diffusion-based refinement, and graph-based subset selection reduces correspondence redundancy while maintaining robust pose estimation across challenging baselines.
Prateeth Rao
International Institute of Information Technology Bangalore, Bengaluru, India
Camera pose estimation is a key step in 3D reconstruction and view-synthesis pipelines. We present a deep, global Structure-from-Motion framework based on learned view-graph aggregation. Our method employs a permutation-equivariant, edge-conditioned graph neural network that takes noisy pairwise relative poses as input and outputs globally consistent camera extrinsics. The network is trained without ground-truth supervision, relying solely on a relative-pose consistency objective. This is followed by 3D point triangulation and robust bundle adjustment. Our approach is efficient, scalable to more than a thousand images, and robust to graph density. We evaluate our method on MegaDepth, 1DSfM, Strecha, and BlendedMVS. These experiments demonstrate that our method achieves superior rotation and translation accuracy compared to deep track-centric methods while registering more images across many scenes, and competitive results compared to state-of-the-art classical pipelines, while being much faster.
Estimating the relative poses of multi-camera systems is a fundamental problem in computer vision, with critical applications in autonomous vehicles, mobile devices, and unmanned aerial vehicles (UAVs). However, existing solutions often suffer from high computational complexity or rely on an excessive number of point correspondences, limiting their real-world applicability. To address these limitations, we propose two efficient minimal solvers for estimating the relative poses of multi-camera systems using a novel parameterization. The first solver leverages the vertical direction prior provided by Inertial Measurement Units (IMUs), while the second utilizes the rotation axis direction prior from IMUs. Our methods require only four point correspondences and reduce the problem of multi-camera relative pose estimation to solving a univariate 6th-degree polynomial, a significant improvement over existing approaches, which typically involve 8th-degree polynomials. This reduction in computational complexity and correspondence requirements makes our solvers particularly effective when integrated into RANSAC frameworks, demonstrating strong potential for visual odometry applications. Through rigorous evaluations on synthetic data and the KITTI benchmark, our methods achieved superior computational efficiency and competitive accuracy compared to state-of-the-art algorithms.
Tao Li, Zhenbao Yu, Banglei Guan +2
College of Aerospace Science and Engineering, Naval Aviation University, Yantai 264000, China · College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410000, China