Abstract
We describe a procedure for automated detection of sunspots from SoHO/MDI full-disk continuum images. The MDI Level-1.8 continuum images were first corrected for the limb darkening and stray light, and then were flat-fielded. Sunspots were extracted using a newly developed automated sunspot detection procedure, which is based on the level set, namely the selective binary and Gaussian function regularized level set (SBGFRLS) method (Zhang et al., Image Vis. Comput. 28, 668, 2010). In this method we initialize a two-dimensional level-set function and evolve it using a signed pressure force (SPF) function. For sunspot detection, the level-set function was defined twice, first for umbra and then for penumbra extraction. Using this procedure, along with the characterization of detected sunspots we have also generated tracking reports of all sunspots in a fully unsupervised manner.
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References
Aschwanden, M.J.: 2010, Image processing techniques and feature recognition in solar physics. Solar Phys. 262, 235 – 275. doi: 10.1007/s11207-009-9474-y .
Beck, J.G., Chapman, G.A.: 1993, A study of the contrast of sunspots from photometric images. Solar Phys. 146, 49 – 60. doi: 10.1007/BF00662169 .
Brandt, P.N., Schmidt, W., Steinegger, M.: 1990, On the umbra–penumbra area ratio of sunspots. Solar Phys. 129, 191 – 194. doi: 10.1007/BF00154373 .
Colak, T., Qahwaji, R.: 2008, Automated McIntosh-based classification of sunspot groups using MDI images. Solar Phys. 248, 277 – 296. doi: 10.1007/s11207-007-9094-3 .
Curto, J.J., Blanca, M., Martínez, E.: 2008, Automatic sunspots detection on full-disk solar images using mathematical morphology. Solar Phys. 250, 411 – 429. doi: 10.1007/s11207-008-9224-6 .
Fonte, C.C., Fernandes, J.: 2009, Application of fuzzy sets to the determination of sunspot areas. Solar Phys. 260, 21 – 41. doi: 10.1007/s11207-009-9436-4 .
Grossmann-Doerth, U., Schmidt, W.: 1981, The brightness distribution in sunspot penumbrae. Astron. Astrophys. 95, 366 – 372.
Győri, L.: 1998, Automation of area measurement of sunspots. Solar Phys. 180, 109 – 130. doi: 10.1023/A:1005081621268 .
Higgins, P.A., Gallagher, P.T., McAteer, R.T.J., Bloomfield, D.S.: 2011, Solar magnetic feature detection and tracking for space weather monitoring. Adv. Space Res. 47, 2105 – 2117. doi: 10.1016/j.asr.2010.06.024 .
Jones, H.P., Chapman, G.A., Harvey, K.L., Pap, J.M., Preminger, D.G., Turmon, M.J., Walton, S.R.: 2008, A comparison of feature classification methods for modeling solar irradiance variation. Solar Phys. 248, 323 – 337. doi: 10.1007/s11207-007-9069-4 .
Kass, M., Witkin, A., Terzopoulos, D.: 1988, Snakes: Active contour models. Int. J. Comput. Vis. 1, 321 – 331. doi: 10.1007/BF00133570 .
Martínez Pillet, V.: 1992, Stray-light effects on the solar intensity distribution. Solar Phys. 140, 207 – 237. doi: 10.1007/BF00146310 .
Mathew, S.K., Martínez Pillet, V., Solanki, S.K., Krivova, N.A.: 2007, Properties of sunspots in cycle 23. I. Dependence of brightness on sunspot size and cycle phase. Astron. Astrophys. 465, 291 – 304. doi: 10.1051/0004-6361:20066356 .
Osher, S., Sethian, J.A.: 1988, Fronts propagating with curvature-dependent speed: Algorithms based on Hamilton–Jacobi formulations. J. Comput. Phys. 79, 12 – 49. doi: 10.1016/0021-9991(88)90002-2 .
Pettauer, T., Brandt, P.N.: 1997, On novel methods to determine areas of sunspots from photoheliograms. Solar Phys. 175, 197 – 203. doi: 10.1023/A:1004903201224 .
Pierce, A.K., Slaughter, C.D.: 1977, Solar limb darkening. I – λλ of 3033 – 7297. Solar Phys. 51, 25 – 41. doi: 10.1007/BF00240442 .
Potts, H.E., Diver, D.A.: 2008, Post-hoc derivation of SOHO Michelson Doppler Imager flat fields. Astron. Astrophys. 492, 863 – 871. doi: 10.1051/0004-6361:200810606 .
Preminger, D.G., Walton, S.R., Chapman, G.A.: 2001, Solar feature identification using contrasts and contiguity. Solar Phys. 202, 53 – 62. doi: 10.1023/A:1011896413891 .
Scherrer, P.H., Bogart, R.S., Bush, R.I., Hoeksema, J.T., Kosovichev, A.G., Schou, J., et al.: 1995, The Solar Oscillations Investigation – Michelson Doppler Imager. Solar Phys. 162, 129 – 188. doi: 10.1007/BF00733429 .
Steinegger, M., Brandt, P.N., Schmidt, W., Pap, J.: 1990, Sunspot photometry and the total solar irradiance deficit measured in 1980 by ACRIM. Astrophys. Space Sci. 170, 127 – 133. doi: 10.1007/BF00652658 .
Steinegger, M., Vazquez, M., Bonet, J.A., Brandt, P.N.: 1996, On the energy balance of solar active regions. Astrophys. J. 461, 478 – 498. doi: 10.1086/177075 .
Turmon, M., Pap, J.M., Mukhtar, S.: 2002, Statistical pattern recognition for labeling solar active regions: Application to SOHO/MDI imagery. Astrophys. J. 568, 396 – 407. doi: 10.1086/338681 .
Verbeeck, C., Higgins, P.A., Colak, T., Watson, F.T., Delouille, V., Mampaey, B., Qahwaji, R.: 2013, A multi-wavelength analysis of active regions and sunspots by comparison of automatic detection algorithms. Solar Phys. 283, 67 – 95. doi: 10.1007/s11207-011-9859-6 .
Watson, F.T., Fletcher, L., Marshall, S.: 2011, Evolution of sunspot properties during solar cycle 23. Astron. Astrophys. 533, A14. doi: 10.1051/0004-6361/201116655 .
Watson, F., Fletcher, L., Dalla, S., Marshall, S.: 2009, Modelling the longitudinal asymmetry in sunspot emergence: The role of the Wilson depression. Solar Phys. 260, 5 – 19. doi: 10.1007/s11207-009-9420-z .
Zhang, K., Zhang, L., Song, H., Zhou, W.: 2010, Active contours with selective local or global segmentation: A new formulation and level set method. Image Vis. Comput. 28, 668 – 676. doi: 10.1016/j.imavis.2009.10.009 .
Zharkov, S., Zharkova, V.V., Ipson, S.S.: 2005, Statistical properties of sunspots in 1996 – 2004: I. Detection, North South asymmetry and area distribution. Solar Phys. 228, 377 – 397. doi: 10.1007/s11207-005-5005-7 .
Zharkov, S., Zharkova, V., Ipson, S., Benkhalil, A.: 2005, Technique for automated recognition of sunspots on full-disk solar images. EURASIP J. Appl. Signal Process. 15, 2573 – 2584. doi: 10.1155/ASP.2005.2573 .
Zharkova, V.V., Aboudarham, J., Zharkov, S., Ipson, S.S., Benkhalil, A.K., Fuller, N.: 2005, Solar feature catalogues in Egso. Solar Phys. 228, 361 – 375. doi: 10.1007/s11207-005-5623-0 .
Acknowledgements
We would like to thank Dr. Kaihua Zhang for providing the SBGFRLS demo code. SoHO is a project of international cooperation between ESA and NASA. The daily sunspot numbers were obtained from the Solar Influences Data Analysis Center (SIDC) at the Royal Observatory of Belgium. The sunspot area data were obtained from the catalog prepared by the Marshall Space Flight Center using the Royal Greenwich Observatory and USAF/NOAA Sunspot Data.
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Goel, S., Mathew, S.K. Automated Detection, Characterization, and Tracking of Sunspots from SoHO/MDI Continuum Images. Sol Phys 289, 1413–1431 (2014). https://doi.org/10.1007/s11207-013-0393-6
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DOI: https://doi.org/10.1007/s11207-013-0393-6