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result(s) for
"Challa, Subhash"
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Fundamentals of Object Tracking
by
Evans, Robin J.
,
Morelande, Mark R.
,
Challa, Subhash
in
Aerospace & Radar Technology
,
Linear programming
,
MATHEMATICS / Linear Programming bisacsh
2011,2012
Kalman filter, particle filter, IMM, PDA, ITS, random sets... The number of useful object-tracking methods is exploding. But how are they related? How do they help track everything from aircraft, missiles and extra-terrestrial objects to people and lymphocyte cells? How can they be adapted to novel applications? Fundamentals of Object Tracking tells you how. Starting with the generic object-tracking problem, it outlines the generic Bayesian solution. It then shows systematically how to formulate the major tracking problems – maneuvering, multiobject, clutter, out-of-sequence sensors – within this Bayesian framework and how to derive the standard tracking solutions. This structured approach makes very complex object-tracking algorithms accessible to the growing number of users working on real-world tracking problems and supports them in designing their own tracking filters under their unique application constraints. The book concludes with a chapter on issues critical to successful implementation of tracking algorithms, such as track initialization and merging.
Bayesian Fusion Algorithm for Inferring Trust in Wireless Sensor Networks
2010
This paper introduces a new Bayesian fusion algorithm to combine more than one trust component (data trust and communication trust) to infer the overall trust between nodes. This research work proposes that one trust component is not enough when deciding on whether or not to trust a specific node in a wireless sensor network. This paper discusses and analyses the results from the communication trust component (binary) and the data trust component (continuous) and proves that either component by itself, can mislead the network and eventually cause a total breakdown of the network. As a result of this, new algorithms are needed to combine more than one trust component to infer the overall trust. The proposed algorithm is simple and generic as it allows trust components to be added and deleted easily. Simulation results demonstrate that a node is highly trustworthy provided that both trust components simultaneously confirm its trustworthiness and conversely, a node is highly untrustworthy if its untrustworthiness is asserted by both components. Index Terms-Trust, Bayesian, Fusion, Sensor, Network, Data, Communication
Journal Article
Bayesian and Dempster-Shafer fusion
2004
The Kalman Filter is traditionally viewed as a prediction-correction filtering algorithm. In this work we show that it can be viewed as a Bayesian fusion algorithm and derive it using Bayesian arguments. We begin with an outline of Bayes theory, using it to discuss well-known quantities such as priors, likelihood and posteriors, and we provide the basic Bayesian fusion equation. We derive the Kalman Filter from this equation using a novel method to evaluate the Chapman-Kolmogorov prediction integral. We then use the theory to fuse data from multiple sensors. Vying with this approach is the Dempster-Shafer theory, which deals with measures of “belief”, and is based on the nonclassical idea of “mass” as opposed to probability. Although these two measures look very similar, there are some differences. We point them out through outlining the ideas of the Dempster-Shafer theory and presenting the basic Dempster-Shafer fusion equation. Finally we compare the two methods, and discuss the relative merits and demerits using an illustrative example.
Journal Article
Sensor fusion-based visual target tracking for autonomous vehicles
2008
In this ariticle, a data fusion based algorithm is proposed to identify and track moving objects for autonomous vehicle navigation. It is a challenging problem because both the object and the cameras are moving. Here, the optical flow vector field, color features, and stereo pair disparities are used as visual features, while the vehicle’s motion-sensor data are used to determine the cameras’ motion. We propose a data fusion algorithm which integrates information obtained from different visual cues and the vehicle’s motion-sensor data for target-tracking. The fusion algorithm determines the velocity and position of the target in the 3D world coordinates. Next, we present a detailed description of the three-dimensional (3D) target-tracking algorithm using an extended Kalman filter. Experimental results are presented to demonstrate the performance of the proposed scheme using different natural image sequences.
Journal Article
Augmented State Integrated Probabilistic Data Association Smoothing for Automatic Track Initiation in Clutter
2006
We introduce a fixed lag smoother algorithm based on the integrated probabilistic data association (IPDA) algorithm. IPDA jointly estimates both the target state and its existence. In this paper the joint density of target state and existence is extended for fixed lag smoothing. The proposed smoothing algorithm is also tested against various multiple target tracking parameters like state RMS estimation, number of true target detected, number of false target confirmed and target termination time and simulation results are also presented in the paper.
Journal Article
Maneuvering object tracking
by
Evans, Robin J.
,
Morelande, Mark R.
,
Challa, Subhash
in
Aerospace & Radar Technology
,
Automatic control engineering
,
Probability & statistics
2011
Maneuvering objects are those objects whose dynamical behavior changes over time. An object that suddenly turns or accelerates displays a maneuvering behavior with regard to its tracked position. While the definition of a maneuvering object extends beyond the tracking of position and speed, historically it is in this context that maneuvering object tracking theory developed. This chapter presents a unified derivation of some of the most common maneuvering object tracking algorithms in the Chapman–Kolmogorov–Bayesian framework.Modeling for maneuvering object trackingIn general, maneuvering object tracking refers to the problem of state estimation where the system model undergoes abrupt changes. The standard Kalman filter with a single motion model is limited in performance for such problems because it does not effectively respond to the changes in the dynamics as the object maneuvers. A large number of approaches to the maneuvering object tracking problem have been developed including process noise adaptation (Singer et al., 1974; Moose, 1975; Gholson and Moose, 1977; Ricker and Williams, 1978; Moose et al., 1979; Farina and Studer, 1985), input estimation (Chan et al., 1979), variable dimension filtering (Bar-Shalom and Birmiwal, 1982) and multiple models (MM) (Ackerson and Fu, 1970; Mori et al., 1986; Blom and Bar-Shalom, 1988; Bar-Shalom and Li, 1993), etc. These apparently diverse approaches may be grouped into two broad categories:single model with state augmentation;multiple models with Markovian jumps.
Book Chapter
Bayesian smoothing algorithms for object tracking
by
Evans, Robin J.
,
Morelande, Mark R.
,
Challa, Subhash
in
Aerospace & Radar Technology
,
Automatic control engineering
,
Probability & statistics
2011
Estimation of an object state at a particular time based on measurements collected beyond that time is generally termed as smoothing or retrodiction. Smoothing improves the estimates compared to the ones obtained by filters owning to the use of more observations (or information). This comes at the cost of a certain time delay. However, these improvements are highly effective in applications like “situation awareness” or “threat assessment.” These higher level applications improve operator efficiency if a more accurate picture of the actual field scenario is provided to them, even if it is with a time delay. For these applications, besides object state, parameters representing the overall scenario, like number of targets, their initiation/termination instants and locations, may prove to be very useful ones. A smoothing algorithm can result in a better estimation of the overall situational picture and thus help increase the effectiveness of the critical applications like situation/ threat awareness. This chapter will introduce the Bayesian formulation of smoothing and derive the established smoothing algorithms under different tracking scenarios: non-maneuvering, maneuvering, clutter and in the presence of object existence uncertainty.Introduction to smoothingFilters, introduced in previous chapters, produce the “best estimate” of the object state at a particular time based on the measurements collected up to that time. Smoothers, on the other hand, produce an estimate of the state at a time based on measurements collected beyond the time in question (the predictor is another estimator where the estimation at a certain time is carried out based on measurements collected until a point before that time).
Book Chapter