Real-time shape retrieval for robotics using skip Tri-Grams

TitleReal-time shape retrieval for robotics using skip Tri-Grams
Publication TypeConference Papers
Year of Publication2009
AuthorsLi Y, Bitsakos K, Fermüller C, Aloimonos Y
Conference NameIEEE/RSJ International Conference on Intelligent Robots and Systems, 2009. IROS 2009
Date Published2009/10/10/15
ISBN Number978-1-4244-3803-7
KeywordsBullseye retrieval test, Clocks, closed contour shape retrieval, Image retrieval, Image segmentation, Indexing, Information retrieval, Intelligent robots, Jacobian matrices, mobile robot, Mobile robots, MPEG 7 shape dataset, piecewise linear segments, Piecewise linear techniques, Real time systems, real-time shape retrieval, robot vision, SHAPE, shape recognition, shape representation, skip Tri-Grams, Testing

The real time requirement is an additional constraint on many intelligent applications in robotics, such as shape recognition and retrieval using a mobile robot platform. In this paper, we present a scalable approach for efficiently retrieving closed contour shapes. The contour of an object is represented by piecewise linear segments. A skip Tri-Gram is obtained by selecting three segments in the clockwise order while allowing a constant number of segments to be ¿skipped¿ in between. The main idea is to use skip Tri-Grams of the segments to implicitly encode the distant dependency of the shape. All skip Tri-Grams are used for efficiently retrieving closed contour shapes without pairwise matching feature points from two shapes. The retrieval is at least an order of magnitude faster than other state-of-the-art algorithms. We score 80% in the Bullseye retrieval test on the whole MPEG 7 shape dataset. We further test the algorithm using a mobile robot platform in an indoor environment. 8 objects are used for testing from different viewing directions, and we achieve 82% accuracy.