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CATEGORIES:Signal Processing and Communications Lab Seminars
SUMMARY:Factor Analysis with a Mixture of Gaussian Factors
\, with Application to Separation of the Cosmic Mi
crowave Background - Prof Simon Wilson\, School of
Computer Science and Statistics\, University Coll
ege\, Dublin
DTSTART;TZID=Europe/London:20090610T141500
DTEND;TZID=Europe/London:20090610T151500
UID:TALK16942AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/16942
DESCRIPTION:We describe an approach to factor analysis/source
separation for multi-channel image data where the
sources are assumed to be Gaussian mixtures\, whic
h may be independent or dependent e.g. mixtures of
multivariate Gaussians. An MCMC procedure has bee
n developed that implements a fully Bayesian proce
dure e.g. it computes the posterior distribution o
f sources\, their Gaussian mixture parameters and
the matrix of linear coefficients from the data.
The method is applied to recovery of the cosmic mi
crowave background \nCMB)\, being an example of so
urce separation applied to image data. The CMB is
one of many sources of extraterrestrial microwave
radiation and we observe a weighted sum of these s
ources from the Earth at different frequencies. It
s accurate reconstruction is of great interest to
astronomers and physicists since knowledge of its
properties\, and in particular its anisotropies\,
will place strong restrictions on current cosmolog
ical theories. From the perspective of a Bayesian
solution\, this application is interesting as the
re is considerable prior information about the lin
ear coefficients and the sources.\nResults from t
he analysis of data from the WMAP satellite will b
e presented\, where microwave radiation is observe
d at 5 frequencies and separated into sources\, in
cluding the CMB. A discussion of the many outstand
ing issues in this problem is also presented.
LOCATION:LR11\, Engineering\, Department of
CONTACT:Rachel Fogg
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