A Holistic Visual Place Recognition Approach using Lightweight CNNs for Severe ViewPoint and Appearance Changes

Recently, deep and complex Convolutional Neural Network (CNN) architectures have achieved encouraging results for Visual Place Recognition under strong viewpoint and appearance changes. However, the significant computation and memory overhead of these CNNs limit their practical deployment for resource-constrained mobile robots that are usually battery-operated. Achieving state-of-the-art performance/accuracy with light-weight CNN architectures is thus highly desirable, but a challenging problem. In this paper, a holistic approach is presented that combines novel regions-based features from a light-weight CNN architecture, pretrained on a place-/scene-centric image database, with Vector of Locally Aggregated Descriptors (VLAD) encoding methodology adapted specifically for Visual Place Recognition problem. The proposed approach is evaluated on a number of challenging benchmark datasets (under strong viewpoint and appearance variations) and achieves an average performance boost of 10\% over state-of-the-art algorithms in terms of Area Under the Curve (AUC) calculated under precision-recall curves.