“…More recent approaches include ranking-loss based learning [56], novel pooling [55], contextual feature reweighting [37], large scale re-training [79], semantics-guided feature aggregation [25,61,72], use of 3D [50,78,40], additional sensors [29,52,22] and image appearance translation [1,54]. Place matches obtained through global descriptor matching are often re-ranked using sequential information [24,82,46], query expansion [28,13], geometric verification [38,25,49] and feature fusion [80,83]. Distinct from existing approaches, this paper introduces Patch-NetVLAD, which reverses the local-to-global process of image description by deriving multi-scale patch features from a global descriptor, NetVLAD.…”