✨ Contributions

The main contributions of this approach can be classified into separate

A Visual SLAM Framework

A multi-threaded real-time VSLAM, able to recognize, localize, and map building components for less pose and localization errors

Rich Map Reconstruction

A novel methodology for extracting structural elements (i.e., rooms and corridors) from detected building components (i.e., walls and grounds)

Environment-Specific Element Validation

An algorithm for verifying and enriching geometric objects with their corresponding semantic entities

Real-world Experiments

Conducting real-world experiments under various indoor conditions to assess the effectiveness of the proposed approach

📊 Evaluations

🖼️ I. Qualitative Results (Generated Scene Graphs)

In vS-Graphs, the Building Components Recognition module extracts semantic entities such as walls and ground surfaces from each KeyFrame using a panoptic segmentation backbone that provides pixel-level labels and instance boundaries. A parallel Structural Elements Recognition thread then infers higher-level entities (rooms and floors) by grouping spatially consistent components into enclosed areas and aggregating them across building levels. This hierarchical reasoning enhances spatial understanding and enables geometry-aware optimization in vS-Graphs. Below, you can find some qualitative results of the generated scene graphs on different datasets, where bc and se refer to the building components and structural elements, respectively.

🏷️ AutoSense Dataset

🏷️ ICL Dataset

🏷️ OpenLoris Dataset

🏷️ TUM-RGBD Dataset


📈 II. Absolute Trajectory Error (ATE)

Below table shows the performance of vS-Graphs on different datasets and compared to the state-of-the-art methods. It is measured using ATE reported in meters. For evaluation, each system was evaluated over eight runs on dataset instances.


📍 III. Mapping Performance

Analyzing the accuracy of the reconstructed maps against the ground truch across eight iterations shows that vS-Graphs performs more robost compared to its baseline, ORB-SLAM 3.0. The performance is measured using Root Mean Square Error (RMSE) reported in meters. vS-Graphs achieves superior performance in terms of RMSE, despite generating maps with around 10.15% fewer points (on average).

  • AutoSense Dataset - Sequence SR01
  • AutoSense Dataset - Sequence SR02
  • AutoSense Dataset - Sequence SR03
  • AutoSense Dataset - Sequence MR01
  • AutoSense Dataset - Sequence MR02
  • AutoSense Dataset - Sequence MR03

🖼️ IV. Scene Understanding Performance

Below evaluations show the performance of vS-Graphs in terms of scene understanding. The results are presented in the form of reconstructed maps enriched with building components (i.e., walls and ground surfaces). These building components are later used to infer the structural elements of the environment (i.e., rooms and floors).


Detected / Real Precision Recall
Method Sequence BC SE BC SE BC SE
S-Graphs (link) MR01 11 / 14 4 / 4 0.92 1.00 0.92 1.00
MR02 12 / 13 4 / 4 1.00 1.00 0.92 1.00
MR03 20 / 22 6 / 6 0.90 1.00 0.95 1.00
Hydra (link) MR01 N/A 4 / 4 N/A 1.00 N/A 1.00
MR02 N/A 6 / 4 N/A 0.75 N/A 0.75
MR03 N/A 6 / 6 N/A 1.00 N/A 0.80
vGraphs (link) MR01 13 / 14 4 / 4 0.86 1.00 1.00 1.00
MR02 13 / 13 4 / 4 0.92 1.00 0.92 1.00
MR03 23 / 22 6 / 6 0.96 1.00 1.00 1.00


⏱️ V. Runtime Analysis

vS-Graphs achieves real-time performance with an average processing rate of 22 ± 3 FPS, exceeding the 20 FPS threshold for real-time operation. Below, you can see the timeline of thread execution while processing a sample dataset instance.

🚀 Team

Core Team

Ali Tourani


Doctoral Researcher

SnT, University of Luxembourg

Saad Ejaz


Doctoral Researcher

SnT, University of Luxembourg

Miguel Fernandez-Cortizas

Postdoc Researcher

SnT, University of Luxembourg

Asier Bikandi-Noya

Doctoral Researcher

SnT, University of Luxembourg

Jose Luis Sanchez-Lopez

Research Scientist

SnT, University of Luxembourg

Holger Voos


Full Professor

SnT, University of Luxembourg

Former Team Members

Hriday Bavle

GAMMA AR

Luxembourg

External Collaborators

David Morilla-Cabello

Ph.D. Student

Universidad de Zaragoza, Spain

David Pérez Saura

Ph.D. Student

Universidad Politécnica de Madrid, Spain

📝 Citation

@article{vsgraphs,
title={vS-Graphs: Integrating Visual SLAM and Situational Graphs through Multi-level Scene Understanding},
author={A. Tourani, S. Ejaz, H. Bavle, D. Morilla-Cabello, J.L. Sanchez-Lopez, H. Voos},
year={2025},
url={https://arxiv.org/abs/2503.01783}
}
@article{tourani2024towards,
title={Towards Localizing Structural Elements: Merging Geometrical Detection with Semantic Verification in RGB-D Data},
author={A. Tourani, S. Ejaz, H. Bavle, J.L. Sanchez-Lopez, H. Voos},
year={2024},
url={https://arxiv.org/abs/2409.06625}
}

☎️ Contact Us

https://www.uni.lu/snt-en/research-groups/arg/
https://github.com/snt-arg
6, rue Coudenhove-Kalergi, L-1359 LUXEMBOURG
Block E, Automation and Robotics Group (ARG)