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An improved scheme for detection and labelling in Johansson displays

Fanti, Claudio and Polito, Marzia and Perona, Pietro (2004) An improved scheme for detection and labelling in Johansson displays. In: Advances in Neural Information Processing Systems. Advances in Neural Information Processing Systems . Vol.16. MIT Press , Cambridge, MA, pp. 1603-1610. ISBN 0-262-20152.

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Consider a number of moving points, where each point is attached to a joint of the human body and projected onto an image plane. Johannson showed that humans can effortlessly detect and recognize the presence of other humans from such displays. This is true even when some of the body points are missing (e.g. because of occlusion) and unrelated clutter points are added to the display. We are interested in replicating this ability in a machine. To this end, we present a labelling and detection scheme in a probabilistic framework. Our method is based on representing the joint probability density of positions and velocities of body points with a graphical model, and using Loopy Belief Propagation to calculate a likely interpretation of the scene. Furthermore, we introduce a global variable representing the body's centroid. Experiments on one motion-captured sequence suggest that our scheme improves on the accuracy of a previous approach based on triangulated graphical models, especially when very few parts are visible. The improvement is due both to the more general graph structure we use and, more significantly, to the introduction of the centroid variable.

Item Type:Book Section
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URLURL TypeDescription
Perona, Pietro0000-0002-7583-5809
Additional Information:We are very grateful to Max Welling, who Ørst proposed the idea of using LBP to solve for the optimal labelling in a 2001 Research Note, and who gave many useful suggestion. Sequences W1 and W2 used in the experiments were collected by L. Goncalves and E. di Bernando. This work was partially funded by the NSF Center for Neuromorphic Systems Engineering grant EEC-9402726 and by the ONR MURI grant N00014-01-1-0890.
Funding AgencyGrant Number
NSF Center for Neuromorphic Systems Engineering (CNSE), CaltechEEC-940272
ONR MURIN00014-01-1-0890
Series Name:Advances in Neural Information Processing Systems
Record Number:CaltechAUTHORS:20140730-101718695
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47609
Deposited By: Caroline Murphy
Deposited On:19 Aug 2014 22:33
Last Modified:03 Oct 2019 06:55

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