Bibcode
Lopez Ariste, Arturo; Rees, David E.; Socas-Navarro, Hector; Lites, Bruce W.
Bibliographical reference
Proc. SPIE Vol. 4477, p. 96-106, Astronomical Data Analysis, Jean-Luc Starck; Fionn D. Murtagh; Eds.
Advertised on:
11
2001
Citations
2
Refereed citations
2
Description
Measuring vector magnetic fields in the solar atmosphere using the
profiles of the Stokes parameters of polarized spectral lines split by
the Zeeman effect is known as Stokes Inversion. This inverse problem is
usually solved by least-squares fitting of the Stokes profiles. However
least-squares inversion is too slow for the new generation of solar
instruments (THEMIS, SOLIS, Solar-B, ...) which will produce an
ever-growing flood of spectral data. The solar community urgently
requires a new approach capable of handling this information explosion,
preferably in real-time. We have successfully applied pattern
recognition and machine learning techniques to tackle this problem. For
example, we have developed PCA-inversion, a database search technique
based on Principal Component Analysis of the Stokes profiles. Search is
fast because it is carried out in low dimensional PCA feature space,
rather than the high dimensional space of the spectral signals. Such a
data compression approach has been widely used for search and retrieval
in many areas of data mining. PCA-inversion is the basis of a new
inversion code called FATIMA (Fast Analysis Technique for the Inversion
of Magnetic Atmospheres). Tests on data from HAO's Advanced Stokes
Polarimeter show that FATIMA isover two orders of magnitude faster than
least squares inversion. Initial tests on an alternative code (DIANNE -
Direct Inversion based on Artificial Neural NEtworks) show great promise
of achieving real-time performance. In this paper we present the latest
achievements of FATIMA and DIANNE, two powerful examples of how pattern
recognition techniques can revolutionize data analysis in astronomy.