ConvSequential-SLAM: A Sequence-based, Training-less Visual Place Recognition Technique for Changing Environments
This addresses robust place recognition for robotics and autonomous systems in dynamic environments, though it is incremental as it blends existing methods.
The paper tackles visual place recognition under changing conditions by combining SeqSLAM and CoHOG into ConvSequential-SLAM, achieving state-of-the-art performance on 4 datasets compared to 8 contemporary techniques.
Visual Place Recognition (VPR) is the ability to correctly recall a previously visited place under changing viewpoints and appearances. A large number of handcrafted and deep-learning-based VPR techniques exist, where the former suffer from appearance changes and the latter have significant computational needs. In this paper, we present a new handcrafted VPR technique that achieves state-of-the-art place matching performance under challenging conditions. Our technique combines the best of 2 existing trainingless VPR techniques, SeqSLAM and CoHOG, which are each robust to conditional and viewpoint changes, respectively. This blend, namely ConvSequential-SLAM, utilises sequential information and block-normalisation to handle appearance changes, while using regional-convolutional matching to achieve viewpoint-invariance. We analyse content-overlap in-between query frames to find a minimum sequence length, while also re-using the image entropy information for environment-based sequence length tuning. State-of-the-art performance is reported in contrast to 8 contemporary VPR techniques on 4 public datasets. Qualitative insights and an ablation study on sequence length are also provided.