doi:10.1016/j.inffus.2005.09.010
Copyright © 2005 Elsevier B.V. All rights reserved.
Decentralized Bayesian algorithms for active sensor networks
Alexei Makarenko
, a,
and Hugh Durrant-Whytea
aARC Centre of Excellence in Autonomous Systems (CAS), The University of Sydney, Bdg. J04, NSW 2006, Australia
Received 23 November 2004;
revised 23 August 2005;
accepted 5 September 2005.
Available online 28 November 2005.
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Abstract
The paper presents two algorithms for Decentralized Bayesian information fusion and information-theoretic decision making. The algorithms are stated in terms of operations on a general probability density function representing a single feature of the environment. Several specific density representations are then considered—Gaussian, discrete, Certainty Grid, and hybrid. Well known algorithms for these representations are shown to fit the general pattern. Stating the algorithms in Bayesian terms has a practical advantage of allowing a generic software implementation. The algorithms are described in the context of the active sensor network architecture—a modular framework for decentralized cooperative information fusion and decision making. An example of decentralized target tracking is provided. The algorithms and the framework implementation is illustrated with the results of two indoor deployment scenarios.
Keywords: Decentralized information fusion; Decentralized decision making; Active sensor networks; Mobile robots
Fig. 1. Structural diagram of interactions between canonical components used in information fusion. Two types of belief sources are shown: robotic sensor and human ui, as well as two types of belief sinks: robotic planner and human ui.
Fig. 2. A possible realization of the node component. Information flow to and from a node is also shown. Events corresponding to the four groups of messages occur asynchronously.
Fig. 3. Information flow in the Local Filter on arrival of a local observation. (Message 1 in Fig. 2.)
Fig. 4. Information flow in the Channel Filter on arrival of channel update message. (Message 2 in Fig. 2.)
Fig. 5. Information flow in the Local Filter on arrival of channel update message. (Message 2.1 in Fig. 2.)
Fig. 6. Information flow in the Channel Filter on local update. (Message 3 in Fig. 2.)
Fig. 7. Information flow in the Local Filter on sink update. (Message 4 in Fig. 2.)
Fig. 8. Structural diagram of the decision making task. Two types of action sources are shown: human ui and robotic planner. Services used in implementing the task of information fusion are omitted for clarity.
Fig. 9. Information flow inside planner in coordinated mode.
Fig. 10. Information flow inside planner in cooperative mode.
Fig. 11. Two-node information fusion example: (a) component diagram and (b) information flow between the component. Each node has a single local sensor. The two nodes are linked into a network through the Linkable interface.
Fig. 12. Motion and observation models for non-linear filtering: (a) Gaussian motion model and (b) probability of detection for an acoustic sensor [5]. Darker colors correspond to higher probability.
Fig. 13. Example of decentralized target tracking using nonlinear filtering techniques. The panels show platform positions (□) and current true target position (
). Darker colors correspond to higher probability.
Fig. 14. Entropy evolution in the grid tracking example.
Fig. 15. The information fusion experiments: the “motion” map (a) and point feature tracking (b). Blue lines stand for DDF links. Tracking point features: (c) operator enters feature 2 and (d) platforms drive to and observe it.