Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets
Modern magnetic microscopy (MM) provides high-resolution, ultra-high-sensitivity moment magnetometry, with the ability to measure at spatial resolutions better than 10⁻⁴ m and to detect magnetic moments weaker than 10⁻¹⁵ Am². These characteristics make modern MM devices capable of particularly high-...
| Main Authors: | , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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Terrapub
2019
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| Online Access: | http://hdl.handle.net/1721.1/120504 https://orcid.org/0000-0003-3113-3415 |
| _version_ | 1811080485879676928 |
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| author | Myre, Joseph M Lascu, Ioan Lima, Eduardo A Feinberg, Joshua M Saar, Martin O Myre, Joseph M. Feinberg, Joshua M. Saar, Martin O. Lima, Eduardo A. Weiss, Benjamin P. |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Myre, Joseph M Lascu, Ioan Lima, Eduardo A Feinberg, Joshua M Saar, Martin O Myre, Joseph M. Feinberg, Joshua M. Saar, Martin O. Lima, Eduardo A. Weiss, Benjamin P. |
| author_sort | Myre, Joseph M |
| collection | MIT |
| description | Modern magnetic microscopy (MM) provides high-resolution, ultra-high-sensitivity moment magnetometry, with the ability to measure at spatial resolutions better than 10⁻⁴ m and to detect magnetic moments weaker than 10⁻¹⁵ Am². These characteristics make modern MM devices capable of particularly high-resolution analysis of the magnetic properties of materials, but generate extremely large data sets. Many studies utilizing MM attempt to solve an inverse problem to determine the magnitude of the magnetic moments that produce the measured component of the magnetic field. Fast Fourier techniques in the frequency domain and non-negative least-squares (NNLS) methods in the spatial domain are the two most frequently used methods to solve this inverse problem. Although extremely fast, Fourier techniques can produce solutions that violate the non-negativity of moments constraint. Inversions in the spatial domain do not violate non-negativity constraints, but the execution times of standard NNLS solvers (the Lawson and Hanson method and Matlab’s lsqlin) prohibit spatial domain inversions from operating at the full spatial resolution of an MM. In this paper, we present the applicability of the TNT-NN algorithm, a newly developed NNLS active set method, as a means to directly address the NNLS routine hindering existing spatial domain inversion methods. The TNT-NN algorithm enhances the performance of spatial domain inversions by accelerating the core NNLS routine. Using a conventional computing system, we show that the TNT-NN algorithm produces solutions with residuals comparable to conventional methods while reducing execution time of spatial domain inversions from months to hours or less. Using isothermal remanent magnetization measurements of multiple synthetic and natural samples, we show that the capabilities of the TNT-NN algorithm allow scans with sizes that made them previously inaccesible to NNLS techniques to be inverted. Ultimately, the TNT-NN algorithm enables spatial domain inversions of MM data on an accelerated timescale that renders spatial domain analyses for modern MM studies practical. In particular, this new technique enables MM experiments that would have required an impractical amount of inversion time such as high-resolution stepwise magnetization and demagnetization and 3-dimensional inversions. Keywords: Magnetic microscopy; Rock magnetism; Non-negative least-squares |
| first_indexed | 2024-09-23T11:32:26Z |
| format | Article |
| id | mit-1721.1/120504 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:32:26Z |
| publishDate | 2019 |
| publisher | Terrapub |
| record_format | dspace |
| spelling | mit-1721.1/1205042024-05-15T03:17:31Z Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets Myre, Joseph M Lascu, Ioan Lima, Eduardo A Feinberg, Joshua M Saar, Martin O Myre, Joseph M. Feinberg, Joshua M. Saar, Martin O. Lima, Eduardo A. Weiss, Benjamin P. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Lima, Eduardo A. Weiss, Benjamin P Modern magnetic microscopy (MM) provides high-resolution, ultra-high-sensitivity moment magnetometry, with the ability to measure at spatial resolutions better than 10⁻⁴ m and to detect magnetic moments weaker than 10⁻¹⁵ Am². These characteristics make modern MM devices capable of particularly high-resolution analysis of the magnetic properties of materials, but generate extremely large data sets. Many studies utilizing MM attempt to solve an inverse problem to determine the magnitude of the magnetic moments that produce the measured component of the magnetic field. Fast Fourier techniques in the frequency domain and non-negative least-squares (NNLS) methods in the spatial domain are the two most frequently used methods to solve this inverse problem. Although extremely fast, Fourier techniques can produce solutions that violate the non-negativity of moments constraint. Inversions in the spatial domain do not violate non-negativity constraints, but the execution times of standard NNLS solvers (the Lawson and Hanson method and Matlab’s lsqlin) prohibit spatial domain inversions from operating at the full spatial resolution of an MM. In this paper, we present the applicability of the TNT-NN algorithm, a newly developed NNLS active set method, as a means to directly address the NNLS routine hindering existing spatial domain inversion methods. The TNT-NN algorithm enhances the performance of spatial domain inversions by accelerating the core NNLS routine. Using a conventional computing system, we show that the TNT-NN algorithm produces solutions with residuals comparable to conventional methods while reducing execution time of spatial domain inversions from months to hours or less. Using isothermal remanent magnetization measurements of multiple synthetic and natural samples, we show that the capabilities of the TNT-NN algorithm allow scans with sizes that made them previously inaccesible to NNLS techniques to be inverted. Ultimately, the TNT-NN algorithm enables spatial domain inversions of MM data on an accelerated timescale that renders spatial domain analyses for modern MM studies practical. In particular, this new technique enables MM experiments that would have required an impractical amount of inversion time such as high-resolution stepwise magnetization and demagnetization and 3-dimensional inversions. Keywords: Magnetic microscopy; Rock magnetism; Non-negative least-squares 2019-02-19T20:13:28Z 2019-02-19T20:13:28Z 2019-02 2018-08 2019-02-05T04:48:31Z Article http://purl.org/eprint/type/JournalArticle 1880-5981 1343-8832 http://hdl.handle.net/1721.1/120504 Myre, Joseph M. et al. "Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets." Earth, Planets and Space 71 (February 2019): 14 © 2019 The Author(s) https://orcid.org/0000-0003-3113-3415 en https://doi.org/10.1186/s40623-019-0988-8 Earth, Planets and Space Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ The Author(s) application/pdf Terrapub Springer Berlin Heidelberg |
| spellingShingle | Myre, Joseph M Lascu, Ioan Lima, Eduardo A Feinberg, Joshua M Saar, Martin O Myre, Joseph M. Feinberg, Joshua M. Saar, Martin O. Lima, Eduardo A. Weiss, Benjamin P. Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| title | Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| title_full | Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| title_fullStr | Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| title_full_unstemmed | Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| title_short | Using TNT-NN to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| title_sort | using tnt nn to unlock the fast full spatial inversion of large magnetic microscopy data sets |
| url | http://hdl.handle.net/1721.1/120504 https://orcid.org/0000-0003-3113-3415 |
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