System and process for tracking an object state using a particle filter sensor fusion technique
First Claim
1. A computer-implemented process for tracking an object state over time using particle filter sensor fusion and a plurality of logical sensor modules, comprising using a computer to perform the following process actions for each iteration of the tracking process:
- inputting an object state estimate into a fuser module from each logical sensor module as determined by an object state tracker of that sensor module, wherein the object state estimates are in the form of a Gaussian distribution;
using the fuser module to combine the object state estimate distributions to form a proposal distribution, and then sampling the proposal distribution to produce a series of particles which are provided to each of the logical sensor modules;
using an object state verifier of each logical sensor module to estimate the likelihood of each provided particle;
inputting the likelihood estimates from each logical sensor into the fuser module and computing a combined likelihood model for the particles;
using the fuser module to compute a weight for each particle from the combined likelihood model, the proposal distribution, an object dynamics model which models the changes in the object state over time, and the weight associated with a corresponding particle in the last tracking iteration; and
using the fuser module to compute a final estimate of the object state for the current tracking iteration using the particles and the particle weights, wherein said final object state estimate takes the form of a distribution.
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Abstract
A system and process for tracking an object state over time using particle filter sensor fusion and a plurality of logical sensor modules is presented. This new fusion framework combines both the bottom-up and top-down approaches to sensor fusion to probabilistically fuse multiple sensing modalities. At the lower level, individual vision and audio trackers can be designed to generate effective proposals for the fuser. At the higher level, the fuser performs reliable tracking by verifying hypotheses over multiple likelihood models from multiple cues. Different from the traditional fusion algorithms, the present framework is a closed-loop system where the fuser and trackers coordinate their tracking information. Furthermore, to handle non-stationary situations, the present framework evaluates the performance of the individual trackers and dynamically updates their object states. A real-time speaker tracking system based on the proposed framework is feasible by fusing object contour, color and sound source location.
42 Citations
30 Claims
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1. A computer-implemented process for tracking an object state over time using particle filter sensor fusion and a plurality of logical sensor modules, comprising using a computer to perform the following process actions for each iteration of the tracking process:
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inputting an object state estimate into a fuser module from each logical sensor module as determined by an object state tracker of that sensor module, wherein the object state estimates are in the form of a Gaussian distribution;
using the fuser module to combine the object state estimate distributions to form a proposal distribution, and then sampling the proposal distribution to produce a series of particles which are provided to each of the logical sensor modules;
using an object state verifier of each logical sensor module to estimate the likelihood of each provided particle;
inputting the likelihood estimates from each logical sensor into the fuser module and computing a combined likelihood model for the particles;
using the fuser module to compute a weight for each particle from the combined likelihood model, the proposal distribution, an object dynamics model which models the changes in the object state over time, and the weight associated with a corresponding particle in the last tracking iteration; and
using the fuser module to compute a final estimate of the object state for the current tracking iteration using the particles and the particle weights, wherein said final object state estimate takes the form of a distribution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A two-level, closed-loop, particle filter sensor fusion system for tracking an object state over time, comprising:
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a general purpose computing device;
a computer program comprising program modules executable by the computing device, wherein the computing device is directed by the program modules of the computer program to, access an object state estimate from each of a plurality of logical sensors as determined by an object state tracker of the sensor, combine the object state estimates to form a proposal distribution, sample the proposal distribution to produce a series of particles which are provided to each of the logical sensors to estimate the likelihood of each particle using an object state verifier, access the likelihood estimates from each logical sensor and compute a combined likelihood model for the particles, compute a weight for each particle, compute a final estimate of the object state for the current tracking iteration using the particles and the particle weights. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A computer-readable medium having computer-executable instructions for tracking an object state over time using particle filter sensor fusion and a plurality of logical sensors, said computer-executable instructions comprising for each tracking iteration:
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inputting an object state estimate from each logical sensor;
combining the object state estimates to form a proposal distribution;
sampling the proposal distribution to produce a series of particles;
using the logical sensors to estimate the likelihood of each particle;
inputting the likelihood estimates from each logical sensor;
computing a weight for each particle based in part on the likelihood estimates input from each logical sensor; and
computing a final estimate of the object state for the current tracking iteration using the particles and the particle weights. - View Dependent Claims (22)
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23. A process for tracking an object state over time using particle filter sensor fusion and a plurality of logical sensor modules, comprising the following process actions for each iteration of the tracking process:
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inputting an object state estimate into a fuser module from each logical sensor module as determined by an object state tracker of that sensor module;
using the fuser module to combine the object state estimates to form a proposal distribution, and then sampling the proposal distribution to produce a series of particles which are provided to each of the logical sensor modules;
using an object state verifier of each logical sensor module to estimate the likelihood of each provided particle;
inputting the likelihood estimates from each logical sensor into the fuser module and computing a combined likelihood model for the particles;
using the fuser module to compute a weight for each particle based in part on the combined likelihood model; and
using the fuser module to compute a final estimate of the object state for the current tracking iteration using the particles and the particle weights. - View Dependent Claims (24, 25, 26)
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27. A process for tracking an object state over time using particle filter sensor fusion and a plurality of logical sensor modules, comprising the following process actions for each iteration of the tracking process:
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inputting an object state estimate from each logical sensor;
combining the object state estimates to form a proposal distribution;
sampling the proposal distribution to produce a series of particles;
using the logical sensors to estimate the likelihood of each particle;
computing a weight for each particle based in part on the likelihood estimates from each logical sensor; and
computing a final estimate of the object state for the current tracking iteration using the particles and the particle weights. - View Dependent Claims (28)
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29. A two-level, closed-loop, particle filter sensor fusion system for tracking an object state over time, comprising:
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a general purpose computing device;
a computer program comprising program modules executable by the computing device, wherein the computing device is directed by the program modules of the computer program to, access an object state estimate from each of a plurality of logical sensors, combine the object state estimates to form a proposal distribution, sample the proposal distribution to produce a series of particles which are provided to each of the logical sensors to estimate the likelihood of each particle, access the likelihood estimates from each logical sensor, compute a weight for each particle base in part on the likelihood estimates, compute a final estimate of the object state for the current tracking iteration using the particles and the particle weights. - View Dependent Claims (30)
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Specification