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Title: PARAMETER-FREE AUTOMATIC SOLAR ACTIVE REGION DETECTION BY HERMITE FUNCTION DECOMPOSITION

Abstract

We present a new method for the automated detection of sunspots and active regions (ARs) from full-disk observations of the photospheric Stokes vector. The algorithm relies on a Hermite function decomposition of observed Stokes polarization profiles as a function of position on the solar disk. This approach is unique in that it requires no user-defined tunable parameters, like intensity or magnetic field thresholds, and utilizes no information traditionally exploited by other detection schemes to signal the presence of an AR. It is truly a black-box approach, utilizing a self-consistent statistical analysis of the Hermite coefficients. We present the method and show the results of its application to Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph full-disk observations. Detection efficiency is presented for a one-month time series of daily photospheric observations, and we derive a skill-score for the method during this time period.

Authors:
 [1]
  1. National Solar Observatory (NSO), 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
Publication Date:
OSTI Identifier:
22089803
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal, Supplement Series
Additional Journal Information:
Journal Volume: 203; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0067-0049
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALGORITHMS; ASTRONOMY; ASTROPHYSICS; DATA ANALYSIS; DETECTION; IMAGE PROCESSING; MAGNETIC FIELDS; PHOTOSPHERE; POLARIZATION; SUN; SUNSPOTS; VECTORS

Citation Formats

Harker, Brian J., E-mail: bharker@nso.edu. PARAMETER-FREE AUTOMATIC SOLAR ACTIVE REGION DETECTION BY HERMITE FUNCTION DECOMPOSITION. United States: N. p., 2012. Web. doi:10.1088/0067-0049/203/1/7.
Harker, Brian J., E-mail: bharker@nso.edu. PARAMETER-FREE AUTOMATIC SOLAR ACTIVE REGION DETECTION BY HERMITE FUNCTION DECOMPOSITION. United States. doi:10.1088/0067-0049/203/1/7.
Harker, Brian J., E-mail: bharker@nso.edu. Thu . "PARAMETER-FREE AUTOMATIC SOLAR ACTIVE REGION DETECTION BY HERMITE FUNCTION DECOMPOSITION". United States. doi:10.1088/0067-0049/203/1/7.
@article{osti_22089803,
title = {PARAMETER-FREE AUTOMATIC SOLAR ACTIVE REGION DETECTION BY HERMITE FUNCTION DECOMPOSITION},
author = {Harker, Brian J., E-mail: bharker@nso.edu},
abstractNote = {We present a new method for the automated detection of sunspots and active regions (ARs) from full-disk observations of the photospheric Stokes vector. The algorithm relies on a Hermite function decomposition of observed Stokes polarization profiles as a function of position on the solar disk. This approach is unique in that it requires no user-defined tunable parameters, like intensity or magnetic field thresholds, and utilizes no information traditionally exploited by other detection schemes to signal the presence of an AR. It is truly a black-box approach, utilizing a self-consistent statistical analysis of the Hermite coefficients. We present the method and show the results of its application to Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph full-disk observations. Detection efficiency is presented for a one-month time series of daily photospheric observations, and we derive a skill-score for the method during this time period.},
doi = {10.1088/0067-0049/203/1/7},
journal = {Astrophysical Journal, Supplement Series},
issn = {0067-0049},
number = 1,
volume = 203,
place = {United States},
year = {2012},
month = {11}
}