Efficient retrieval of arbitrary objects from long-term robot observations.

We present a novel method for efficient querying and retrieval of arbitrarily shaped objects from large amounts of unstructured 3D point cloud data. Our approach first performs a convex segmentation of the data after which local features are extracted and stored in a feature dictionary. We show that the representation allows efficient and reliable querying of the data. To handle arbitrarily shaped objects, we propose a scheme which allows incremental matching of segments based on similarity to the query object. Further, we adjust the feature metric based on the quality of the query results to improve results in a second round of querying. We perform extensive qualitative and quantitative experiments on two datasets for both segmentation and retrieval, validating the results using ground truth data. Comparison with other state of the art methods further enforces the validity of the proposed method. Finally, we also investigate how the density and distribution of the local features within the point clouds influence the quality of the results.