Solar Physics

, Volume 262, Issue 2, pp 399–423 | Cite as

A Code for Automated Tracing of Coronal Loops Approaching Visual Perception

  • Markus J. AschwandenEmail author
Solar Image Processing and Analysis


We develop a new numerical code with automated feature extraction, customized for tracing of coronal loops, a method we call Oriented Coronal CUrved Loop Tracing (OCCULT), which for the first time breaks even with the results of visual tracing. The method used is based on oriented-directivity tracing of curvi-linear features, but in contrast to other general feature-extraction algorithms, it is customized for solar EUV and SXR images by taking advantage of the specific property that coronal loops have large curvature radii compared with their widths. We evaluate the performance of this new code by comparing the cumulative distribution of loop lengths, the median and maximum loop lengths, the completeness of detection, and the congruency of the detected features with other numerical codes and visual tracings. We find that the new code closely approaches the results of visual perception and outperforms the other existing numerical codes. This algorithm is useful for the 3D reconstruction of the geometry, motion, and oscillations of coronal loops, with single or stereoscopic spacecraft, as well as for modeling of the loop hydrodynamics and the coronal magnetic field.


Sun: EUV Sun: magnetic fields Methods: pattern recognition 


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  1. Andrews, M.D.: 2001, Solar Phys. 204, 181. CrossRefADSGoogle Scholar
  2. Aschwanden, M.J.: 2004, Physics of the Solar Corona – An Introduction, Praxis Publishing Ltd., Chichester, Springer, Berlin. Google Scholar
  3. Aschwanden, M.J.: 2005, Solar Phys. 228, 339. CrossRefADSGoogle Scholar
  4. Aschwanden, M.J.: 2010, Image processing techniques and feature recognition in solar physics. Solar Phys., doi: 10.1007/s11214-009-9505-x.
  5. Aschwanden, M.J., Alexander, D.: 2001, Solar Phys. 204, 91. CrossRefADSGoogle Scholar
  6. Aschwanden, M.J., Nightingale, R.W., Alexander, D.: 2000, Astrophys. J. 541, 1059. CrossRefADSGoogle Scholar
  7. Aschwanden, M.J., Schrijver, C.J., Alexander, D.: 2001, Astrophys. J. 550, 1036. CrossRefADSGoogle Scholar
  8. Aschwanden, M.J., Newmark, J.S., Delaboudinière, J.-P., Neupert, W.M., Klimchuk, J.A., Gary, G.A., Portier-Fozzani, F., Zucker, A.: 1999a, Astrophys. J. 515, 842. CrossRefADSGoogle Scholar
  9. Aschwanden, M.J., Fletcher, L., Schrijver, C., Alexander, D.: 1999b, Astrophys. J. 520, 880. CrossRefADSGoogle Scholar
  10. Aschwanden, M.J., Lee, J.K., Gary, G.A., Smith, M., Inhester, B.: 2008a, Solar Phys. 248, 359. CrossRefADSGoogle Scholar
  11. Aschwanden, M.J., Wülser, J.P., Nitta, N., Lemen, J.: 2008b, Astrophys. J. 679, 827. CrossRefADSGoogle Scholar
  12. Aulanier, G., DeLuca, E.E., Antiochos, S.K., McMullen, R.A., Golub, L.: 2000, Astrophys. J. 540, 1126. CrossRefADSGoogle Scholar
  13. Berger, T.E., De Pontieu, B., Schrijver, C.J., Title, A.M.: 1999, Solar Phys. 190, 409. CrossRefADSGoogle Scholar
  14. DeRosa, M.L., Schrijver, C.J., Barnes, G., Leka, K.D., Lites, B.W., Aschwanden, M.J., Amari, T., Canou, A., McTiernan, J.M., Regnier, S., Thalmann, J., Valori, G., Wheatland, M.S., Wiegelmann, T., Cheung, M.C.M., Conlon, P.A., Fuhrmann, M., Inhester, B., Tadesse, T.: 2009, Astrophys. J. 696, 1780. CrossRefADSGoogle Scholar
  15. Durak, N., Nasraoui, O., Schmelz, J.: 2009, Pattern Recogn. 42, 2481. zbMATHCrossRefGoogle Scholar
  16. Durak, N., Nasraoui, O., Schmelz, J.: 2010, Solar Phys., submitted. Google Scholar
  17. Freeland, S.L., Handy, B.N.: 1998, Solar Phys. 182, 497. CrossRefADSGoogle Scholar
  18. Gary, A., Alexander, D.: 1999, Solar Phys. 186, 123. CrossRefADSGoogle Scholar
  19. Gonzalez, R.C., Woods, R.E.: 2008, Digital Image Processing, 3rd edn., Pearson Prentice Hall, Upper Saddle River. Google Scholar
  20. Handy, B.N., Acton, L.W., Kankelborg, C.C., Wolfson, C.J., Akin, D.J., Bruner, M.E., Caravalho, R., Catura, R.C., Chevalier, R., Duncan, D.W., et al.: 1999, Solar Phys. 187, 229. CrossRefADSGoogle Scholar
  21. Inhester, B., Feng, L., Wiegelmann, T.: 2007, Solar Phys. 248, 379. CrossRefADSGoogle Scholar
  22. Jähne, B.: 2005, Digital Image Processing, 6th edn., Springer, Berlin. Google Scholar
  23. Klimchuk, J.A.: 2000, Solar Phys. 193, 53. CrossRefADSGoogle Scholar
  24. Lee, J.K., Newman, T.S., Gary, G.A.: 2004, In: Kittler, J., Petrou, M., Nixon, M.S. (eds.) Proc. 17th International Conference on Pattern Recognition (ICPR), IEEE-CS, Washington, 315. doi: 10.1109/ICPR.2004.1333766. Google Scholar
  25. Lee, J.K., Newman, T.S., Gary, G.A.: 2006a, Pattern Recogn. 39, 246. CrossRefGoogle Scholar
  26. Lee, J.K., Newman, T.S., Gary, G.A.: 2006b, In: Proc. 7th IEEE SSIAI, Denver, CO, 91. Google Scholar
  27. Lopez Fuentes, M.C., Demoulin, P., Klimchuk, J.A.: 2008, Astrophys. J. 673, 586. CrossRefADSGoogle Scholar
  28. Lundquist, L.L., Fisher, G.M., Metcalf, T.R., Leka, K.D., McTiernan, J.M.: 2008, Astrophys. J. 689, 1388. CrossRefADSGoogle Scholar
  29. McAteer, R.T., Kestener, P., Arneodo, A., Khalil, A.: 2010, Solar Phys., submitted. Google Scholar
  30. Nakariakov, V.M., Ofman, L., DeLuca, E., Roberts, B., Davila, J.M.: 1999, Science 285, 862. CrossRefADSGoogle Scholar
  31. Pao, Y.-H.: 1996, Adaptive Pattern Recognition and Neural Networks, Addison-Wesley, New York. Google Scholar
  32. Raghupathy, K.: 2004, PhD Thesis, Cornell University. Google Scholar
  33. Ripley, B.D.: 1996, Pattern Recognition and Neural Networks, Cambridge University Press, Cambridge. zbMATHGoogle Scholar
  34. Sandman, A., Aschwanden, M.J., DeRosa, M., Wülser, J.P., Alexander, D.: 2009, Solar Phys. 259, 1. CrossRefADSGoogle Scholar
  35. Schrijver, C.J., Sandman, A.W., Aschwanden, M.J., DeRosa, M.L.: 2004, Astrophys. J. 615, 512. CrossRefADSGoogle Scholar
  36. Schrijver, C.J., DeRosa, M.L., Title, A.M., Metcalf, T.R.: 2005, Astrophys. J. 628, 501. CrossRefADSGoogle Scholar
  37. Schrijver, C.J., DeRosa, M., Metcalf, T.R., Liu, Y., McTiernan, J., Regnier, S., Valori, G., Wheatland, M.S., Wiegelmann, T.: 2006, Solar Phys. 235, 161. CrossRefADSGoogle Scholar
  38. Schrijver, C.J., DeRosa, M.L., Metcalf, T., Barnes, G., Lites, B., Tarbell, T., McTiernan, J., Valori, G., Wiegelmann, T., Wheatland, M.S., Amari, T., Aulanier, G., Demoulin, P., Fuhrmann, M., Kusano, K., Regnier, S., Thalmann, J.K.: 2008, Astrophys. J. 675, 1637. CrossRefADSGoogle Scholar
  39. Sellah, S., Nasraoui, O.: 2008, In: Tools with Artificial Intelligence, ICTAI’08, 20th IEEE Internat. Conf. 2, 45. doi: 10.1109/ICTAI.2008.147.
  40. Somov, B.V., Kosugi, T., Hudson, H.S., Sakao, T.: 2002, Astrophys. J. 579, 863. CrossRefADSGoogle Scholar
  41. Steger, L.H.: 1996, Technical Report FGBV-96-03, Forschungsgruppe Bildverstehen (FG BV), Informatik IX, Technische Universität München, Germany. Google Scholar
  42. Tian, L., Wang, J., Wu, D.: 2002, Solar Phys. 209, 375. CrossRefADSGoogle Scholar
  43. Tsiklauri, D., Aschwanden, M.J., Nakariakov, V.M., Arber, T.D.: 2004, Astron. Astrophys. 419, 1149. CrossRefADSGoogle Scholar
  44. Wang, H., Liu, C., Deng, Y., Zhang, H.: 2005, Astrophys. J. 627, 1031. CrossRefADSGoogle Scholar
  45. Warren, H.P., Winebarger, A.R.: 2007, Astrophys. J. 666, 1245. CrossRefADSGoogle Scholar
  46. Winebarger, A.R., Warren, H.P.: 2005, Astrophys. J. 626, 543. CrossRefADSGoogle Scholar
  47. Yan, Y., Huang, G.: 2003, Space Sci. Rev. 107, 111. CrossRefADSGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Solar and Astrophysics LaboratoryLockheed Martin Advanced Technology Center, Dept. ADBSPalo AltoUSA

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