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Improved appearance-based matching in similar and dynamic environments using a Vocabulary tree

In this paper we present a topological map building algorithm based on a Vocabulary Tree that is robust to features present in dynamic or similar environments. The algorithm recognises incorrect loop closures, not supported by the odometry, and uses this information to update the feature weights in the tree to suppress further associations from these features. Two methods of adjusting these feature entropies are proposed, one decreasing entropy related to incorrect features in a uniform manner and the other proportional to the contribution of the said feature. Preliminary results showing the performance of the proposed method are presented where it is found that by adjusting the feature entropies, the number of incorrect associations can be reduced while improving the quality of the correct matches.