From IntRoLab

RTAB-Map RTAB-Map : Real-Time Appearance-Based Mapping


This page is about the loop closure detection approach used by RTAB-Map. For RGB-D mapping, visit introlab.github.io/rtabmap.

Loop closure detection is the process involved when trying to find a match between the current and a previously visited locations in SLAM (Simultaneous Localization And Mapping).

Over time, the amount of time required to process new observations increases with the size of the internal map, which may affect real-time processing. RTAB-Map is a novel real-time loop closure detection approach for large-scale and long-term SLAM. Our approach is based on efficient memory management to keep computation time for each new observation under a fixed time limit, thus respecting real-time limit for long-term operation. Results demonstrate the approach's adaptability and scalability using two custom data sets and ten standard data sets.


Note that these results (more recent) may differ from those in the presentation video above...

Figure 1: Summary of the loop closures detected on UdeS data set :

  • Green : Loop closures detected
  • Yellow : Loop closures rejected
  • Red : Unable to detect a loop closure because old places could not be retrieved

Figure 2: Processing time for each image acquired (real-time limit fixed to 700 ms for an image rate of 1 Hz)

Figure 3: Precision-Recall (48% recall at 100% precision)

RTAB-Map LoopClosureMapResults.png RTAB-Map LoopClosureTimeResults.png RTAB-Map RecallResults.png

Reproduce the loop closure detection results

RTAB-Map LoopClosureAllPrecisionRecall.png


  • Newer:
  • Older:

Source code[edit]

The code was tested on Windows (Xp, 7), Mac OS X 10.6 and Ubuntu 10.4LTS.

Images acquired in Need For Speed Most Wanted

Data sets[edit]


  • 5395 images at 1 Hz (1.5 hours).
  • Images taken while walking through a loop of ~2 km, traversed two times.
  • The data set contains indoor and outdoor environments.
UdeS_1Hz GroundTruth


  • 25098 images at 1 Hz (7 hours).
  • Images taken from the racing video game Need For Speed: Most Wanted.
  • 2 areas visited hundred times each (100 traversals in area 1 then moved to area 2 for another 102 traversals).


Community data sets from other loop closure detection approaches :

Ground truths:


  1. M. Labbé and F. Michaud, “Multi-Session Visual SLAM for Illumination-Invariant Re-Localization in Indoor Environments,” in Frontiers in Robotics and AI, vol. 9, 2022. (pdf) (Frontiers)
  2. M. Labbé and F. Michaud, “RTAB-Map as an Open-Source Lidar and Visual SLAM Library for Large-Scale and Long-Term Online Operation,” in Journal of Field Robotics, vol. 36, no. 2, pp. 416–446, 2019. (pdf) (Wiley)
  3. M. Labbé and F. Michaud, “Long-term online multi-session graph-based SPLAM with memory management,” in Autonomous Robots, vol. 42, no. 6, pp. 1133-1150, 2017. (pdf) (Springer)
  4. M. Labbé and F. Michaud, “Online Global Loop Closure Detection for Large-Scale Multi-Session Graph-Based SLAM,” in Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, 2014. (pdf) (IEEE Xplore)
  5. Labbé, M., Michaud., F. (2013), “Appearance-based loop closure detection in real-time for large-scale and long-term operation,” IEEE Transactions on Robotics, vol. 29, no. 3, pp. 734-745. (pdf) (IEEE Xplore)
  6. Labbé, M., Michaud, F. (2011), “Memory management for real-time appearance-based loop closure detection,” in Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems. (pdf) (IEEE Xplore)


  • M. Labbé, "Simultaneous Localization and Mapping (SLAM) with RTAB-Map", Université Laval, Québec, November 2015 (slides pdf)