An Overview of Existing Algorithms for Resolving the 180° Ambiguity in Vector Magnetic Fields: Quantitative Tests with Synthetic Data
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2,242 citations
Cites methods from "An Overview of Existing Algorithms ..."
...A further product is computed as the final vector field by applying a field direction disambiguation technique, since the Stokes parameters cannot distinguish the polarity of the component of the field normal to the line-of-sight (Metcalf, 1994; Metcalf et al., 2006; Leka et al., 2009)....
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599 citations
Cites background or methods from "An Overview of Existing Algorithms ..."
...This method has been shown to be among the best performing on a wide range of tests on synthetic data for which the answer is known (Metcalf et al., 2006; Leka et al., 2009)....
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...A plethora of methods have been proposed to resolve this ambiguity (for an overview, see Metcalf et al., 2006)....
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...A neighboring-pixel acute-angle algorithm based on the University of Hawai’i Iterative method (UHIM; Canfield et al., 1993; Metcalf et al., 2006) that locally maximizes the sum of the dot product of the field at one pixel with the field at its neighbors is used....
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443 citations
Cites methods from "An Overview of Existing Algorithms ..."
...…algorithms to do this, we chose as an alternative to AZAM to employ the automated University of Hawai‘i Iterative Method (UHIM) (Canfield et al. 1993) because it has been used extensively in the literature and also scored highly amongst other ambiguity resolution algorithms (Metcalf et al. 2006)....
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...We choose to perform the disambiguation using the interactive Azimuthal Ambiguity Method (AZAM), which is one of several methods have been devised and tested to resolve this ambiguity (see Metcalf et al. 2006, and references therein)....
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422 citations
343 citations
Cites methods from "An Overview of Existing Algorithms ..."
...The algorithm applied includes the enhancements described in Metcalf et al. (2006) and was the top-performing automated method among those compared in that same study....
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References
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"An Overview of Existing Algorithms ..." refers methods in this paper
...Hence, the “simulated annealing” algorithm (Metropolis et al., 1953; Kirkpatrick et al., 1983) is used to find the global minimum, an extremely robust approach when faced with a large, discrete problem (there are two and only two possibilities at each pixel) with many local minima (Metcalf, 1994)....
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2,154 citations
1,910 citations
"An Overview of Existing Algorithms ..." refers methods in this paper
...…condition can be alleviated by padding the observed line-of-sight field with non-vector data from an instrument with a large field-of-view (e.g. SOHO/MDI, Scherrer et al., 1995), padding the boundary data with zeroes, or by assuming the walls of the extrapolation box are perfectly conducting....
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568 citations
"An Overview of Existing Algorithms ..." refers methods in this paper
...The code is part of a code-tree which includes a program that computes a best-fit α , selected by minimizing the difference between the transverse components of the observed field and the linear force-free field (Leka and Skumanich, 1999; Pevtsov et al., 1995)....
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