BoQ: A Place is Worth a Bag of Learnable Queries
Authors: Amar Ali-bey, Brahim Chaib-draa, Philippe Giguère

In visual place recognition accurately identifying and matching images of locations under varying environmental conditions and viewpoints remains a significant challenge. In this paper we introduce a new technique called Bag-of-Queries (BoQ) which learns a set of global queries designed to capture universal place-specific attributes. Unlike existing techniques that employ self-attention and generate the queries directly from the input BoQ employ distinct learnable global queries which probe the input features via cross-attention ensuring consistent information aggregation. In addition this technique provides an interpretable attention mechanism and integrates with both CNN and Vision Transformer backbones. The performance of BoQ is demonstrated through extensive experiments on 14 large-scale benchmarks. It consistently outperforms current state-of-the-art techniques including NetVLAD MixVPR and EigenPlaces. Moreover despite being a global retrieval technique (one-stage) BoQ surpasses two-stage retrieval methods such as Patch-NetVLAD TransVPR and R2Former all while being orders of magnitude faster and more efficient. The code and model weights are publicly available at https://github.com/amaralibey/Bag-of-Queries.