Organizations: The Hong Kong University of Science and Technology (GuangZhou) · University of Liverpool · Hong Kong Polytechnic University · Xi’an Jiaotong-Liverpool University
Long-sequence panoramic reconstruction requires detailed scene geometry and globally consistent camera poses across distant revisits. Panoramic SLAM and incremental SfM rely on feature correspondences, but repeated, similar structures and small partial overlap make reliable long-range connections difficult to establish, leaving accumulated drift unresolved. Feed-forward models offer detailed local geometry, but their high computational costs limit inference window size, necessitating additional constraints for global consistency. This motivates combining continuous feature-based tracking and sparse mapping with rapid, high-quality local reconstruction from feed-forward models to achieve accurate localization and globally consistent dense mapping over long sequences. We therefore propose a panoramic reconstruction framework that couples an ORB-based sparse panoramic mapping frontend with a fine-tuned feed-forward model. Our key insight is that predicted local geometry enables 3D verification of feature matches across distant revisits, yielding long-range camera constraints even between regions. We calibrate predicted depths with sparse landmarks and use verified connections to optimize the global pose graph, updating dense geometry with the corrected camera poses. We also introduce PanoRecon, a seven-scene benchmark with repetitive architecture, large and small loops, and reference camera poses and LiDAR geometry for evaluating global consistency. Our method achieves the lowest mean absolute trajectory error and high F-1 Score among the evaluated methods. Project Page:https://zhuoxiaoli.github.io/HoloRecon_page/
Figures & tables
Figure 1: Overview of the proposed method. Sparse landmarks calibrate Pi3 depths, and registered panoramic cameras place them in the map. These predictions support cross-view ORB correspondences for verifying long-range camera constraints. Global correction and observation fusion refine the sparse map, which recalibrates and repositions the cached dense geometry.
Figure 2: Cross-view evidence for a global connection.
Figure 3: Dataset statistics and GT examples of the PanoRecon benchmark.
Method
360LOC
YUTO MMS
PanoRecon
ATE ↓
RPE-t ↓
RPE-r ↓
ATE ↓
RPE-t ↓
RPE-r ↓
ATE ↓
RPE-t ↓
RPE-r ↓
Feed-Forward
PanoVGGT (ERP)
OOM
OOM
OOM
OOM
OOM
OOM
OOM
OOM
OOM
Scal3R (Pinhole)
5.366
0.124
1.354
187.407
2.911
1.025
9.794
0.282
0.340
SLAM
360DVO (ERP)
0.954
0.026
0.039
68.313
0.183
0.011
2.799
0.104
0.039
Table 1: Quantitative comparison of localization. Mean scene-wise RMSE on 360LOC (4 scenes), YUTO MMS (4 sequences), and PanoRecon (7 scenes). OOM denotes GPU out-of-memory.
Figure 4: Qualitative comparison of localization.
Method
360LOC
YUTO MMS
PanoRecon
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
Stella-vSLAM-Dense (ERP)
62.42
58.23
58.68
23.78
14.52
17.24
36.61
31.10
31.97
COLMAP (Pinhole)
81.27
44.79
57.25
29.15
13.23
17.28
71.32
51.83
59.75
Ours (ERP)
79.22
52.87
62.04
60.56
40.77
48.71
64.22
62.36
63.16
Table 2: Quantitative comparison of dense reconstruction. Mean scene-wise precision (P), recall (R), and F-score (F) in percent, at 20 cm on 360LOC (4 scenes), YUTO MMS (4 sequences), and PanoRecon (7 scenes). Higher is better.
Figure 5: Point-cloud comparison on the Residence2 and Road scenes of the PanoRecon benchmark.
Backend
Solve (s) ↓
Total BA (s) ↓
Speedup ↑
Reproj. RMSE ↓
CPU (OpenMP, 32 threads)
19.430
32.649
1.00×
0.8466
GPU (CUDA Schur)
2.244
7.581
4.31×
0.8420
Table 3: CPU and GPU bundle adjustment.
Table 9Table 10
Appendix figures & tables24 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 7: Visualization of ours PanoRecon benchmark ground-truth LiDAR geometry.
Figure 8: From online submaps to globally consistent geometry. (a) Online pose estimation and local reconstruction. (b) Submap alignment, with distinct colors indicating different submaps. (c) Candidate selection from geometric overlap. (d) Graph correction using verified long-range connections. (e) BA and realignment remove the duplicated building surfaces left by pose drift after online alignment.
Figure 9: Point-cloud comparison of building facades and local structures in the PanoRecon benchmark’s Building1 scene.
Figure 10: Point-cloud comparison in the Residence scene.
Figure 11: Point-cloud comparison in the HPC scene.
Figure 12: Point-cloud comparison in the 360LOC Concourse scene.
Figure 13: Point-cloud comparison in the YUTO MMS Sequence B scene.
Figure 14: Point-cloud comparison in the YUTO MMS Sequence C scene.
Quantity
Requirement
Total inliers, small / large correction
≥60 / ≥100
Inlier fraction, small / large correction
≥0.35 / ≥0.50
Unique features per side
≥40
Supporting keyframes per side
≥3 , each with ≥10 inliers
Scale / rotation / mean camera displacement
[2/3,1.5] / ≤15∘ / ≤50h
Bidirectional distance / viewing angle
≤0.3 / ≤1∘
Appendix
Table 8: Connection-verification thresholds. Distances use map units, and h is the median keyframe spacing.
Ours
COLMAP (Pinhole)
Stage
Time
Stage
Time
Frontend processing
42.71
Feature extraction
7.21
Pi3 inference
38.96
Matching and verification
26.17
Connection matching
44.66
Rig verification
7.39
Connection verification
11.94
Incremental reconstruction + BA
618.52
Pose-graph optimization
10.08
Photometric MVS
227.33
Appendix
Table 9: Key-stage runtime on YUTO MMS Sequence C. Times are in minutes, excluding separate preprocessing and export.
Configuration
ATE ↓
RPE-t ↓
RPE-r ↓
Precision ↑
Recall ↑
F-score ↑
(m)
(m)
( ∘ )
(%)
(%)
(%)
Default SL(4)
Failed at submap 57/59
Adapted SE(3)
26.831
0.430
3.616
2.31
45.83
4.40
Without loop factors SE(3)
29.970
0.294
0.112
4.55
51.09
8.35
Ours submap alignment Sim(3)
4.203
0.107
0.149
10.60
78.14
18.67
Appendix
Table 10: Adapt PanoVGGT with VGGT-SLAM on Residence2.
Figure 15: Applying Submap Alignment to PanoVGGT
Figure 16: Reconstruction Result on 360loc Dataset Hall Scene.
Figure 17: Reconstruction Result on Ours PanoRecon Benchmark Residence1 Scene.
Figure 18: Reconstruction Result on Ours PanoRecon Benchmark Road Scene.
Figure 19: Reconstruction Result on Ours PanoRecon Benchmark Residence2 Scene.
Figure 20: Reconstruction Result on YUTO MMS Benchmark Sequence B Scene.
Figure 21: Reconstruction Result on YUTO MMS Benchmark Sequence C Scene.
Atrium
Concourse
Method
n
ATE ↓
RPE-t ↓
RPE-r ↓
Method
n
ATE ↓
RPE-t ↓
RPE-r ↓
Scal3R
581
3.322
0.095
0.841
Scal3R
491
5.717
0.130
0.611
360DVO
581
0.654
0.044
0.034
360DVO
491
0.779
0.011
0.044
Open-vSLAM
580
0.255
0.691
22.408
Open-vSLAM
471
0.081
0.670
20.111
Stella-vSLAM
285
1.209
0.083
0.059
Stella-vSLAM
262
0.172
0.037
0.298
COLMAP (ERP)
581
0.201
0.043
0.033
COLMAP (ERP)
491
0.131
0.007
0.038
Appendix
Table 11: 360LOC localization by scene. ATE and RPE-t are in meters; RPE-r is in degrees. n is the number of associated poses (scene panels) or available/expected scenes (Mean). All errors are RMSE; lower is better.
Sequence A
Sequence B
Method
n
ATE ↓
RPE-t ↓
RPE-r ↓
Method
n
ATE ↓
RPE-t ↓
RPE-r ↓
Scal3R
234
24.591
0.301
0.409
Scal3R
2794
307.710
0.948
0.381
360DVO
234
0.244
0.006
0.010
360DVO
2794
135.769
0.277
0.013
Open-vSLAM
235
35.215
15.562
56.725
Open-vSLAM
2794
479.963
37.245
1.025
Stella-vSLAM
235
0.370
0.026
0.060
Stella-vSLAM
2794
252.571
1.074
0.223
COLMAP (ERP)
234
0.161
0.008
0.014
COLMAP (ERP)
2794
412.900
2.060
0.197
Appendix
Table 12: YUTO MMS localization by scene. ATE and RPE-t are in meters; RPE-r is in degrees. n is the number of KF poses or available/expected scenes (Mean).
Building 1
Building 2
Method
n
ATE ↓
RPE-t ↓
RPE-r ↓
Method
n
ATE ↓
RPE-t ↓
RPE-r ↓
Scal3R
765
14.643
0.281
0.182
Scal3R
419
3.537
0.223
0.128
360DVO
765
2.726
0.240
0.023
360DVO
419
4.548
0.175
0.047
Open-vSLAM
765
3.387
2.836
34.833
Open-vSLAM
418
5.764
3.636
0.135
Stella-vSLAM
765
2.506
0.411
0.646
Stella-vSLAM
418
5.018
1.024
0.121
COLMAP (ERP)
765
10.831
15.002
8.499
COLMAP (ERP)
419
5.369
0.202
0.048
Appendix
Table 13: PanoRecon localization by scene. ATE and RPE-t are in meters; RPE-r is in degrees. n is the number of associated poses (scene panels) or available/expected scenes (Mean). All errors are RMSE; lower is better.
Scene
Stella-vSLAM-Dense
COLMAP (Pinhole)
Ours
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
Atrium
47.83
76.16
58.76
67.84
46.63
55.27
65.51
66.92
66.20
Concourse
77.73
59.92
67.67
85.15
54.85
66.72
83.88
52.27
64.40
Hall
71.55
49.30
58.38
77.85
34.27
47.59
85.95
36.60
51.34
Piatrium
52.58
47.53
49.93
94.22
43.40
59.43
81.57
55.71
66.20
Appendix
Table 14: 360LOC dense reconstruction by scene. P/R/F in percent at 20 cm. Colors rank methods within each scene and metric.
Scene
Stella-vSLAM-Dense
COLMAP (Pinhole)
Ours
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
Sequence A
46.13
39.25
42.41
88.09
49.94
63.74
88.77
62.81
73.56
Sequence B
18.74
4.19
6.85
10.13
0.81
1.50
48.63
32.51
38.97
Sequence C
13.42
7.10
9.29
9.85
1.36
2.39
66.52
43.20
52.38
Sequence D
16.84
7.51
10.39
8.51
0.81
1.48
38.31
24.56
29.93
Appendix
Table 15: YUTO MMS dense reconstruction by scene. P/R/F in percent at 20 cm. Colors rank methods within each scene and metric.
Scene
Stella-vSLAM-Dense
COLMAP (Pinhole)
Ours
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
P ↑
R ↑
F ↑
Building 1
22.72
37.68
28.34
86.74
71.51
78.39
70.69
68.87
69.77
Building 2
49.98
55.64
52.66
67.20
62.37
64.69
64.06
58.56
61.19
Gym
34.40
10.87
16.52
58.60
41.62
48.67
66.03
53.86
59.33
HPC
51.50
30.84
38.58
84.42
55.84
67.21
65.74
66.36
66.05
Residence
50.17
52.52
51.32
89.47
56.71
69.42
76.00
74.44
75.22
Appendix
Table 16: PanoRecon dense reconstruction by scene. P/R/F in percent at 20 cm. Colors rank methods within each scene and metric.