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Through the lens of doubt: robust and efficient uncertainty estimation for visual place recognition

Through the lens of doubt: robust and efficient uncertainty estimation for visual place recognition
Through the lens of doubt: robust and efficient uncertainty estimation for visual place recognition

Visual Place Recognition (VPR) enables robots and autonomous vehicles to identify previously visited locations by matching current observations against a database of known places. However, VPR systems face significant challenges when deployed across varying visual environments, lighting conditions, seasonal changes, and viewpoints changes. Failure-critical VPR applications, such as loop closure detection in simultaneous localization and mapping (SLAM) pipelines, require robust estimation of place matching uncertainty. We propose three training-free uncertainty metrics that estimate prediction confidence by analyzing inherent statistical patterns in similarity scores from any existing VPR method. Similarity Distribution (SD) quantifies match distinctiveness by measuring score separation between candidates; Ratio Spread (RS) evaluates competitive ambiguity among top-scoring locations; and Statistical Uncertainty (SU) is a combination of SD and RS that provides a unified metric that generalizes across datasets and VPR methods without requiring validation data to select the optimal metric. All three metrics operate without additional model training, architectural modifications, or computationally expensive geometric verification. Comprehensive evaluation across nine state-of-the-art VPR methods and six benchmark datasets confirms that our metrics excel at discriminating between correct and incorrect VPR matches, and consistently outperform existing approaches while maintaining negligible computational overhead, making it deployable for real-time robotic applications across varied environmental conditions with improved precision-recall performance.

Deep Learning for Visual Perception, Localization, Vision-Based Navigation
2377-3766
5899-5906
Hafez, Muhammad Burhan
e8c991ab-d800-46f2-abeb-cb169a1ed47e
Miller, Emily
b6bd9edc-815e-417b-a9ee-743c8fca5af8
Milford, Michael J.
9edf5ef3-4a6a-4d05-aec2-6146c00cd407
Ramchurn, Gopal
1d62ae2a-a498-444e-912d-a6082d3aaea3
Ehsan, Shoaib
ae8922f0-dbe0-4b22-8474-98e84d852de7
Hafez, Muhammad Burhan
e8c991ab-d800-46f2-abeb-cb169a1ed47e
Miller, Emily
b6bd9edc-815e-417b-a9ee-743c8fca5af8
Milford, Michael J.
9edf5ef3-4a6a-4d05-aec2-6146c00cd407
Ramchurn, Gopal
1d62ae2a-a498-444e-912d-a6082d3aaea3
Ehsan, Shoaib
ae8922f0-dbe0-4b22-8474-98e84d852de7

Hafez, Muhammad Burhan, Miller, Emily, Milford, Michael J., Ramchurn, Gopal and Ehsan, Shoaib (2026) Through the lens of doubt: robust and efficient uncertainty estimation for visual place recognition. IEEE Robotics and Automation Letters, 11 (5), 5899-5906. (doi:10.1109/LRA.2026.3674688).

Record type: Article

Abstract

Visual Place Recognition (VPR) enables robots and autonomous vehicles to identify previously visited locations by matching current observations against a database of known places. However, VPR systems face significant challenges when deployed across varying visual environments, lighting conditions, seasonal changes, and viewpoints changes. Failure-critical VPR applications, such as loop closure detection in simultaneous localization and mapping (SLAM) pipelines, require robust estimation of place matching uncertainty. We propose three training-free uncertainty metrics that estimate prediction confidence by analyzing inherent statistical patterns in similarity scores from any existing VPR method. Similarity Distribution (SD) quantifies match distinctiveness by measuring score separation between candidates; Ratio Spread (RS) evaluates competitive ambiguity among top-scoring locations; and Statistical Uncertainty (SU) is a combination of SD and RS that provides a unified metric that generalizes across datasets and VPR methods without requiring validation data to select the optimal metric. All three metrics operate without additional model training, architectural modifications, or computationally expensive geometric verification. Comprehensive evaluation across nine state-of-the-art VPR methods and six benchmark datasets confirms that our metrics excel at discriminating between correct and incorrect VPR matches, and consistently outperform existing approaches while maintaining negligible computational overhead, making it deployable for real-time robotic applications across varied environmental conditions with improved precision-recall performance.

Text
25-5019_03_MS - Accepted Manuscript
Available under License Creative Commons Attribution.
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More information

e-pub ahead of print date: 16 March 2026
Keywords: Deep Learning for Visual Perception, Localization, Vision-Based Navigation

Identifiers

Local EPrints ID: 510726
URI: http://eprints.soton.ac.uk/id/eprint/510726
ISSN: 2377-3766
PURE UUID: 3f21983d-0021-4790-91fd-c735fab7efaa
ORCID for Muhammad Burhan Hafez: ORCID iD orcid.org/0000-0003-1670-8962
ORCID for Gopal Ramchurn: ORCID iD orcid.org/0000-0001-9686-4302
ORCID for Shoaib Ehsan: ORCID iD orcid.org/0000-0001-9631-1898

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Date deposited: 20 Apr 2026 16:39
Last modified: 21 Apr 2026 02:09

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Contributors

Author: Muhammad Burhan Hafez ORCID iD
Author: Emily Miller
Author: Michael J. Milford
Author: Gopal Ramchurn ORCID iD
Author: Shoaib Ehsan ORCID iD

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