Unifying Local and Global Multimodal Features for Place Recognition in Aliased and Low-Texture Environments

Perceptual aliasing and weak textures pose sig- nificant challenges to the task of place recognition, hinder- ing the performance of Simultaneous Localization and Map- ping (SLAM) systems. This paper presents a novel model, called UMF (standing for Unifying Local and Global Mul- timodal Features) that 1) leverages multi-modality by cross- attention blocks between vision and LiDAR features, and 2) includes a re-ranking stage that re-orders based on local feature matching the top-k candidates retrieved using a global representation. Our experiments, particularly on sequences captured on a planetary-analogous environment, show that UMF outperforms significantly previous baselines in those challenging aliased environments. Since our work aims to enhance the reliability of SLAM in all situations, we also explore its performance on the widely used RobotCar dataset, for broader applicability. Code and models are available at https://github.com/DLR-RM/UMF.