12 research outputs found
Regional variance for multi-object filtering
Recent progress in multi-object filtering has led to algorithms that compute
the first-order moment of multi-object distributions based on sensor
measurements. The number of targets in arbitrarily selected regions can be
estimated using the first-order moment. In this work, we introduce explicit
formulae for the computation of the second-order statistic on the target
number. The proposed concept of regional variance quantifies the level of
confidence on target number estimates in arbitrary regions and facilitates
information-based decisions. We provide algorithms for its computation for the
Probability Hypothesis Density (PHD) and the Cardinalized Probability
Hypothesis Density (CPHD) filters. We demonstrate the behaviour of the regional
statistics through simulation examples
Multi-Bernoulli Sensor-Control via Minimization of Expected Estimation Errors
This paper presents a sensor-control method for choosing the best next state
of the sensor(s), that provide(s) accurate estimation results in a multi-target
tracking application. The proposed solution is formulated for a multi-Bernoulli
filter and works via minimization of a new estimation error-based cost
function. Simulation results demonstrate that the proposed method can
outperform the state-of-the-art methods in terms of computation time and
robustness to clutter while delivering similar accuracy
Representation and estimation of stochastic populations
This work is concerned with the representation and the estimation of populations
composed of an uncertain and varying number of individuals which can randomly
evolve in time. The existing solutions that address this type of problems make the
assumption that all or none of the individuals are distinguishable. In other words,
the focus is either on specific individuals or on the population as a whole. Theses
approaches have complimentary advantages and drawbacks and the main objective
in this work is to introduce a suitable representation for partially-indistinguishable
populations. In order to fulfil this objective, a sufficiently versatile way of quantifying
different types of uncertainties has to be studied. It is demonstrated that this can
be achieved within a measure-theoretic Bayesian paradigm. The proposed representation
of stochastic populations is then used for the introduction of various filtering
algorithms from the most general to the most specific. The modelling possibilities
and the accuracy of one of these filters are then demonstrated in different situations
Multi-object filtering with second-order moment statistics
The focus of this work lies on multi-object estimation techniques, in particular the Probability
Hypothesis Density (PHD) filter and its variations. The PHD filter is a recursive, closed-form estimation
technique which tracks a population of objects as a group, hence avoiding the combinatorics
of data association and therefore yielding a powerful alternative to methods like Multi-Hypothesis
Tracking (MHT). Its relatively low computational complexity stems from strong modelling assumptions
which have been relaxed in the Cardinalized PHD (CPHD) filter to gain more flexibility, but
at a much higher computational cost. We are concerned with the development of two suitable
alternatives which give a compromise between the simplicity and elegance of the PHD filter and
the versatility of the CPHD filter. The first alternative generalises the clutter model of the PHD
filter, leading to more accurate estimation results in the presence of highly variable numbers of false
alarms; the second alternative provides a closed-form recursion of a second-order PHD filter that
propagates variance information along with the target intensity, thus providing more information
than the PHD filter while keeping a much lower computational complexity than the CPHD filter.
The discussed filters are applied on simulated data, furthermore their practicality is demonstrated
on live-cell super-resolution microscopy images to provide powerful techniques for molecule and
cell tracking, stage drift estimation and estimation of background noise
Sensor management for multi-target tracking using random finite sets
Sensor management in multi-target tracking is commonly focused on actively scheduling and managing sensor resources to maximize the visibility of states of a set of maneuvering targets in a surveillance area. This project focuses on two types of sensor management techniques: - controlling a set of mobile sensors (sensor control), and - scheduling the resources of a sensor network (sensor selection). In both cases, agile sensors are employed to track an unknown number of targets. We advocate a Random Finite Set (RFS)-based approach for formulation of a sensor control/selection technique for multi-target tracking problem. Sensor control/scheduling offers a multi-target state estimate that is expected to be substantially more accurate than the classical tracking methods without sensor management. Searching for optimal sensor state or command in the relevant space is carried out by a decision-making mechanism based on maximizing the utility of receiving measurements. In current solutions of sensor management problem, the information of the clutter rate and uncertainty in sensor Field of View (FoV) are assumed to be known in priori. However, accurate measures of these parameters are usually not available in practical situations. This project presents a new sensor management solution that is designed to work within a RFS-based multi-target tracking framework. Our solution does not require any prior knowledge of the clutter distribution nor the probability of detection profile to achieve similar accuracy. Also, we present a new sensor management method for multi-object filtering via maximizing the state estimation confidence. Confidence of an estimation is quantified by measuring the dispersion of the multi-object posterior about its statistical mean using Optimal Sub-Pattern Assignment (OSPA). The proposed method is generic and the presented algorithm can be used with any statistical filter