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A Simple Radial Gradient Filter for Batch-Processing of Coronagraph Images

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Abstract

Images of the extended solar corona, as observed by different white-light coronagraphs, include the K- and F-corona and suffer from a radial variation in intensity. These images require separation of the two coronal components with some additional image-processing to reduce the intensity gradient and analyse the structures and processes occurring at different heights in the solar corona within the full field of view. Over the past few decades, coronagraphs have been producing enormous amounts of data, which will be continued with the launch of new telescopes. To process these bulk coronagraph images with steep radial-intensity gradients, we have developed the algorithm Simple Radial Gradient Filter (SiRGraF). This algorithm is based on subtracting a minimum background (F-corona) created using long-duration images and then dividing the resultant by a uniform-intensity-gradient image to enhance the K-corona. We demonstrate the utility of this algorithm to bring out the short-time-scale transient structures of the corona. SiRGraF can be used to reveal and analyse such structures. It is not suitable for quantitative estimations based on intensity. We have successfully tested the algorithm on images of the Large Angle Spectroscopic COronagraph (LASCO)-C2 onboard the Solar and Heliospheric Observatory (SOHO) and COR-2A onboard the Solar TErrestrial RElations Observatory (STEREO) with good signal-to-noise ratio (SNR) along with low-SNR images of STEREO/COR-1A and the KCoronagraph (KCor). We also compared the performance of SiRGraF with the existing widely used algorithm Normalizing Radial Gradient Filter (NRGF). We found that when hundreds of images have to be processed, SiRGraF works faster than NRGF, providing similar brightness and contrast in the images and separating the transient features. Moreover, SiRGraF works better on low-SNR images of COR-1A than on NRGF, providing better identification of dynamic coronal structures throughout the field of view. We discuss the advantages and limitations of the algorithm. The application of SiRGraF to COR-1 images can be extended for an automated coronal mass ejection (CME) detection algorithm in the future, which will help in our study of the characteristics of CMEs in the inner corona.

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Data Availability

The datasets generated during the current study are available from the corresponding author on reasonable request.

References

  • Banerjee, D., Patel, R., Pant, V.: 2017, The inner coronagraph on board ADITYA-L1 and automatic detection of CMEs. In: Foullon, C., Malandraki, O. (eds.) Space Weather of the Heliosphere: Processes and Forecasts, Proc. Internat. Astron. Union Sympos. 335, Cambridge University Press, Cambridge, 340. DOI.

    Chapter  Google Scholar 

  • Baumbach, S.: 1937, Strahlung, Ergiebigkeit und Elektronendichte der Sonnenkorona. Astron. Nachr. 263, 121. DOI.

    Article  ADS  Google Scholar 

  • Boe, B., Habbal, S., Druckmüller, M., Landi, E., Kourkchi, E., Ding, A., Starha, P., Hutton, J.: 2018, The first empirical determination of the Fe10+ and Fe13+ freeze-in distances in the solar corona. Astrophys. J. 859, 155. DOI. ADS.

    Article  ADS  Google Scholar 

  • Brueckner, G.E., Howard, R.A., Koomen, M.J., Korendyke, C.M., Michels, D.J., Moses, J.D., Socker, D.G., Dere, K.P., Lamy, P.L., Llebaria, A., Bout, M.V., Schwenn, R., Simnett, G.M., Bedford, D.K., Eyles, C.J.: 1995, The Large Angle Spectroscopic Coronagraph (LASCO). Solar Phys. 162, 357. DOI. ADS.

    Article  ADS  Google Scholar 

  • Byrne, J.P., Gallagher, P.T., McAteer, R.T.J., Young, C.A.: 2009, The kinematics of coronal mass ejections using multiscale methods. Astron. Astrophys. 495, 325. DOI. ADS.

    Article  ADS  Google Scholar 

  • Byrne, J.P., Morgan, H., Habbal, S.R., Gallagher, P.T.: 2012, Automatic detection and tracking of coronal mass ejections. II. Multiscale filtering of coronagraph images. Astrophys. J. 752, 145. DOI. ADS.

    Article  ADS  Google Scholar 

  • de Wijn, A.G., Burkepile, J.T., Tomczyk, S., Nelson, P.G., Huang, P., Gallagher, D.: 2012, Stray light and polarimetry considerations for the COSMO K-coronagraph. In: Stepp, L.M., Gilmozzi, R., Hall, H.J. (eds.) Ground-Based and Airborne Telescopes IV, Proc. Soc. Photo-Opt. Instrum. Eng. (SPIE) 8444, 84443N. DOI. ADS.

    Chapter  Google Scholar 

  • DeForest, C.E., Howard, T.A., McComas, D.J.: 2014, Inbound waves in the solar corona: A direct indicator of Alfvén surface location. Astrophys. J. 787, 124. DOI. ADS.

    Article  ADS  Google Scholar 

  • DeForest, C.E., Howard, R.A., Velli, M., Viall, N., Vourlidas, A.: 2018, The highly structured outer solar corona. Astrophys. J. 862, 18. DOI. ADS.

    Article  ADS  Google Scholar 

  • Druckmüller, M.: 2013, A noise adaptive fuzzy equalization method for processing solar extreme ultraviolet images. Astrophys. J. Suppl. 207, 25. DOI. ADS.

    Article  ADS  Google Scholar 

  • Druckmüller, M., Rušin, V., Minarovjech, M.: 2006, A new numerical method of total solar eclipse photography processing. Contrib. Astron. Obs. Skaln. Pleso 36, 131. ADS.

    ADS  Google Scholar 

  • Druckmüllerová, H., Morgan, H., Habbal, S.R.: 2011, Enhancing coronal structures with the Fourier normalizing-radial-graded filter. Astrophys. J. 737, 88. DOI.

    Article  ADS  Google Scholar 

  • Espenak, F.: 2000, Digital compositing techniques for coronal imaging (invited review). In: Livingston, W., Özgüç, A. (eds.) Last Total Solar Eclipse of the Millennium CS-205, Astron. Soc. Pacific, San Francisco, 101. ADS.

    Google Scholar 

  • Habbal, S.R., Druckmüller, M., Morgan, H., Daw, A., Johnson, J., Ding, A., Arndt, M., Esser, R., Rušin, V., Scholl, I.: 2010, Mapping the distribution of electron temperature and Fe charge states in the corona with total solar eclipse observations. Astrophys. J. 708, 1650. DOI. ADS.

    Article  ADS  Google Scholar 

  • Habbal, S.R., Druckmüller, M., Morgan, H., Ding, A., Johnson, J., Druckmüllerová, H., Daw, A., Arndt, M.B., Dietzel, M., Saken, J.: 2011, Thermodynamics of the solar corona and evolution of the solar magnetic field as inferred from the total solar eclipse observations of 2010 July 11. Astrophys. J. 734, 120. DOI. ADS.

    Article  ADS  Google Scholar 

  • He, J.-S., Tu, C.-Y., Marsch, E., Guo, L.-J., Yao, S., Tian, H.: 2009, Upward propagating high-frequency Alfvén waves as identified from dynamic wave-like spicules observed by SOT on Hinode. Astron. Astrophys. 497, 525. DOI. ADS.

    Article  ADS  Google Scholar 

  • Howard, T.: 2011, Coronal Mass Ejections: An Introduction, Astrophys. Space Sci. Lib. 376, Springer, Cham. DOI. ADS.

    Book  Google Scholar 

  • Howard, R.A., Moses, J.D., Vourlidas, A., Newmark, J.S., Socker, D.G., Plunkett, S.P., Korendyke, C.M., Cook, J.W., Hurley, A., Davila, J.M., Thompson, W.T., St. Cyr, O.C., Mentzell, E., Mehalick, K., Lemen, J.R., Wuelser, J.P., Duncan, D.W., Tarbell, T.D., Wolfson, C.J., Moore, A., Harrison, R.A., Waltham, N.R., Lang, J., Davis, C.J., Eyles, C.J., Mapson-Menard, H., Simnett, G.M., Halain, J.P., Defise, J.M., Mazy, E., Rochus, P., Mercier, R., Ravet, M.F., Delmotte, F., Auchere, F., Delaboudiniere, J.P., Bothmer, V., Deutsch, W., Wang, D., Rich, N., Cooper, S., Stephens, V., Maahs, G., Baugh, R., McMullin, D., Carter, T.: 2008, Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI). Space Sci. Rev. 136, 67. DOI. ADS.

    Article  ADS  Google Scholar 

  • Hutton, J., Morgan, H.: 2017, Automated detection of coronal mass ejections in three-dimensions using multi-viewpoint observations. Astron. Astrophys. 599, A68. DOI. ADS.

    Article  ADS  Google Scholar 

  • Koutchmy, S., Altrock, R.C., Darvann, T.A., Dzubenko, N.I., Henry, T.W., Kim, I., Koutchmy, O., Martinez, P., Nitschelm, C., Rubo, G.A.: 1992, Coronal photometry and analysis of the eclipse corona of July 22, 1990. Astron. Astrophys. Suppl. Ser. 96, 169. ADS.

    ADS  Google Scholar 

  • Lamy, P., Llebaria, A., Boclet, B., Gilardy, H., Burtin, M., Floyd, O.: 2020, Coronal photopolarimetry with the LASCO-C2 coronagraph over 24 years [1996 - 2019]. Solar Phys. 295, 89. DOI. ADS.

    Article  ADS  Google Scholar 

  • Lamy, P., Gilardy, H., Llebaria, A., Quémerais, E., Ernandez, F.: 2021, LASCO-C3 observations of the K- and F-coronae over 24 years (1996–2019): Photopolarimetry and electron density distribution. Solar Phys. 296, 76. DOI. ADS.

    Article  ADS  Google Scholar 

  • Lee, J.-O., Cho, K.-S., Lee, K.-S., Cho, I.-H., Lee, J., Miyashita, Y., Kim, Y.-H., Kim, R.-S., Jang, S.: 2020, Formation of post-CME blobs observed by LASCO-C2 and K-Cor on 2017 September 10. Astrophys. J. 892, 129. DOI. ADS.

    Article  ADS  Google Scholar 

  • Lemen, J.R., Title, A.M., Akin, D.J., Boerner, P.F., Chou, C., Drake, J.F., Duncan, D.W., Edwards, C.G., Friedlaender, F.M., Heyman, G.F., Hurlburt, N.E., Katz, N.L., Kushner, G.D., Levay, M., Lindgren, R.W., Mathur, D.P., McFeaters, E.L., Mitchell, S., Rehse, R.A., Schrijver, C.J., Springer, L.A., Stern, R.A., Tarbell, T.D., Wuelser, J.-P., Wolfson, C.J., Yanari, C., Bookbinder, J.A., Cheimets, P.N., Caldwell, D., Deluca, E.E., Gates, R., Golub, L., Park, S., Podgorski, W.A., Bush, R.I., Scherrer, P.H., Gummin, M.A., Smith, P., Auker, G., Jerram, P., Pool, P., Soufli, R., Windt, D.L., Beardsley, S., Clapp, M., Lang, J., Waltham, N.: 2012, The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). Solar Phys. 275, 17. DOI. ADS.

    Article  ADS  Google Scholar 

  • Majumdar, S., Pant, V., Patel, R., Banerjee, D.: 2020, Connecting 3D evolution of coronal mass ejections to their source regions. Astrophys. J. 899, 6. DOI. ADS.

    Article  ADS  Google Scholar 

  • Masson, S., McCauley, P., Golub, L., Reeves, K.K., DeLuca, E.E.: 2014, Dynamics of the transition corona. Astrophys. J. 787, 145. DOI. ADS.

    Article  ADS  Google Scholar 

  • Michelson, A.A.: 1927, Studies in Optics, University of Chicago Press, Chicago. ISBN 9780226523880. books.google.co.in/books?id=FXazQgAACAAJ.

    MATH  Google Scholar 

  • Morgan, H.: 2015, An atlas of coronal electron density at \(5R\odot \) I: Data processing and calibration. Astrophys. J. Suppl. 219, 23. DOI.

    Article  ADS  Google Scholar 

  • Morgan, H., Byrne, J.P., Habbal, S.R.: 2012, Automatically detecting and tracking coronal mass ejections. I. Separation of dynamic and quiescent components in coronagraph images. Astrophys. J. 752, 144.

    Article  ADS  Google Scholar 

  • Morgan, H., Druckmüller, M.: 2014, Multi-scale Gaussian normalization for solar image processing. Solar Phys. 289, 2945. DOI. ADS.

    Article  ADS  Google Scholar 

  • Morgan, H., Habbal, S.R.: 2007, The long-term stability of the visible F corona at heights of 3–6 \(R_{\odot}\). Astron. Astrophys. 471, L47.

    Article  ADS  Google Scholar 

  • Morgan, H., Habbal, S.: 2010, A method for separating coronal mass ejections from the quiescent corona. Astrophys. J. 711, 631. DOI. ADS.

    Article  ADS  Google Scholar 

  • Morgan, H., Habbal, S.R., Woo, R.: 2006, The depiction of coronal structure in white-light images. Solar Phys. 236, 263. DOI. ADS.

    Article  ADS  Google Scholar 

  • Morrill, J.S., Korendyke, C.M., Brueckner, G.E., Giovane, F., Howard, R.A., Koomen, M., Moses, D., Plunkett, S.P., Vourlidas, A., Esfandiari, E., Rich, N., Wang, D., Thernisien, A.F., Lamy, P., Llebaria, A., Biesecker, D., Michels, D., Gong, Q., Andrews, M.: 2006, Calibration of the SOHO/LASCO C3 white light coronagraph. Solar Phys. 233, 331. DOI. ADS.

    Article  ADS  Google Scholar 

  • Müller, D., St. Cyr, O.C., Zouganelis, I., Gilbert, H.R., Marsden, R., Nieves-Chinchilla, T., Antonucci, E., Auchère, F., Berghmans, D., Horbury, T.S., Howard, R.A., Krucker, S., Maksimovic, M., Owen, C.J., Rochus, P., Rodriguez-Pacheco, J., Romoli, M., Solanki, S.K., Bruno, R., Carlsson, M., Fludra, A., Harra, L., Hassler, D.M., Livi, S., Louarn, P., Peter, H., Schühle, U., Teriaca, L., del Toro Iniesta, J.C., Wimmer-Schweingruber, R.F., Marsch, E., Velli, M., De Groof, A., Walsh, A., Williams, D.: 2020, The solar orbiter mission. Science overview. Astron. Astrophys. 642, A1. DOI. ADS.

    Article  Google Scholar 

  • Newkirk, G. Jr., Harvey, J.: 1968, Coronal polar plumes. Solar Phys. 3, 321. DOI. ADS.

    Article  ADS  Google Scholar 

  • Owaki, N., Saito, K.: 1967, Photometry of the solar corona at the 1962 February eclipse. Publ. Astron. Soc. Japan 19, 279. ADS.

    ADS  Google Scholar 

  • Pasachoff, J.M., Rušin, V., Druckmuller, M., Saniga, M.: 2007, Fine structures in the white-light solar corona at the 2006 eclipse. Astrophys. J. 665, 824. DOI.

    Article  ADS  Google Scholar 

  • Patel, R., K, A., Pant, V., Banerjee, D., K., S., Kumar, A.: 2018, Onboard automated cme detection algorithm for the visible emission line coronagraph on ADITYA-L1. Solar Phys. 293, 103. DOI.

    Article  ADS  Google Scholar 

  • Patel, R., Pant, V., Chandrashekhar, K., Banerjee, D.: 2020, A statistical study of plasmoids associated with a post-CME current sheet. Astron. Astrophys. 644, A158. DOI. ADS.

    Article  ADS  Google Scholar 

  • Patel, R., Pant, V., Iyer, P., Banerjee, D., Mierla, M., West, M.J.: 2021, Automated detection of accelerating solar eruptions using parabolic hough transform. Solar Phys. 296, 31. DOI. ADS.

    Article  ADS  Google Scholar 

  • Qiang, Z., Bai, X., Ji, K., Liu, H., Shang, Z.: 2020, Enhancing coronal structures with radial local multi-scale filter. New Astron. 79, 101383. DOI.

    Article  Google Scholar 

  • Raghavendra Prasad, B., Banerjee, D., Singh, J., Nagabhushana, S., Kumar, A., Kamath, P.U., Kathiravan, S., Venkata, S., Rajkumar, N., Natarajan, V., Juneja, M., Somu, P., Pant, V., Shaji, N., Sankarsubramanian, K., Patra, A., Venkateswaran, R., Adoni, A.A., Narendra, S., Haridas, T.R., Mathew, S.K., Krishna, R.M., Amareswari, K., Jaiswal, B.: 2017, Visible emission line coronagraph on ADITYA-L1. Curr. Sci. 113, 613. DOI.

    Article  ADS  Google Scholar 

  • Renotte, E., Baston, E.C., Bemporad, A., Capobianco, G., Cernica, I., Darakchiev, R., Denis, F., Desselle, R., De Vos, L., Fineschi, S., Focardi, M., Górski, T., Graczyk, R., Halain, J.-P., Hermans, A., Jackson, C., Kintziger, C., Kosiec, J., Kranitis, N., Landini, F., Lédl, V., Massone, G., Mazzoli, A., Melich, R., Mollet, D., Mosdorf, M., Nicolini, G., Nicula, B., Orleański, P., Palau, M.-C., Pancrazzi, M., Paschalis, A., Peresty, R., Plesseria, J.-Y., Rataj, M., Romoli, M., Thizy, C., Thomé, M., Tsinganos, K., Wodnicki, R., Walczak, T., Zhukov, A.: 2014, ASPIICS: An externally occulted coronagraph for PROBA-3: Design evolution. In: Oschmann, J.M. Jr., Clampin, M., Fazio, G.G., MacEwen, H.A. (eds.) Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave, Proc. Soc. Photo-Opt. Instrum. Eng. (SPIE) CS-9143, 91432M. DOI. ADS.

    Chapter  Google Scholar 

  • Seetha, S., Megala, S.: 2017, Aditya-L1 mission. Curr. Sci. 113, 610. DOI.

    Article  ADS  Google Scholar 

  • Stenborg, G., Cobelli, P.J.: 2003, A wavelet packets equalization technique to reveal the multiple spatial-scale nature of coronal structures. Astron. Astrophys. 398, 1185. DOI. ADS.

    Article  ADS  Google Scholar 

  • Stenborg, G., Vourlidas, A., Howard, R.A.: 2008, A fresh view of the extreme-ultraviolet corona from the application of a new image-processing technique. Astrophys. J. 674, 1201. DOI. ADS.

    Article  ADS  Google Scholar 

  • Thernisien, A.: 2011, Implementation of the graduated cylindrical shell model for the three-dimensional reconstruction of coronal mass ejections. Astrophys. J. Suppl. 194, 33. DOI. ADS.

    Article  ADS  Google Scholar 

  • Thernisien, A.F.R., Howard, R.A., Vourlidas, A.: 2006, Modeling of flux rope coronal mass ejections. Astrophys. J. 652, 763. DOI. ADS.

    Article  ADS  Google Scholar 

  • Thernisien, A., Vourlidas, A., Howard, R.A.: 2009, Forward modeling of coronal mass ejections using STEREO/SECCHI data. Solar Phys. 256, 111. DOI. ADS.

    Article  ADS  Google Scholar 

  • Thompson, W.T., Wei, K., Burkepile, J.T., Davila, J.M., St. Cyr, O.C.: 2010, Background subtraction for the SECCHI/COR1 telescope aboard STEREO. Solar Phys. 262, 213. DOI. ADS.

    Article  ADS  Google Scholar 

  • van de Hulst, H.C.: 1950, The electron density of the solar corona. Bull. Astron. Inst. Neth. 11, 135.

    ADS  Google Scholar 

  • Woo, R.: 2005, Relating white-light coronal images to magnetic fields and plasma flow. Solar Phys. 231, 71. DOI. ADS.

    Article  ADS  Google Scholar 

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Acknowledgements

We would like to thank the anonymous reviewer for their valuable suggestions, which have enabled us to improve the quality of the manuscript. We would like to thank the IIA and ARIES for providing the required computational facilities. The SECCHI data used here were produced by an international consortium of the Naval Research Laboratory (USA), Lockheed Martin Solar and Astrophysics Lab (USA), NASA Goddard Space Flight Center (USA), Rutherford Appleton Laboratory (UK), University of Birmingham (UK), Max-Planck-Institut for Solar System Research (Germany), Centre Spatiale de Liège (Belgium), Institut d’Optique Théorique et Appliquée (France), and the Institut d’Astrophysique Spatiale (France). SOHO is a project of international cooperation between ESA and NASA. We also thank the Mauna Loa Solar Observatory, operated by the High Altitude Observatory, for making KCor data available. We also thank NASA for making SOHO/LASCO data publicly available.

Funding

R. Patel and S. Majumdar are supported by the Department of Science and Technology, Govt. of India for their research at the IIA and ARIES.

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Authors and Affiliations

  1. Indian Institute of Astrophysics, Koramangala, Bengaluru, 560034, India

    Ritesh Patel, Satabdwa Majumdar & Dipankar Banerjee

  2. Aryabhatta Research Institute of Observational Sciences, Nainital, 263001, India

    Ritesh Patel, Vaibhav Pant & Dipankar Banerjee

  3. University of Calcutta, 87/1, College Street, Kolkata, 700073, India

    Ritesh Patel

  4. Pondicherry University, Chinna Kalapet, Kalapet, Puducherry, 605014, India

    Satabdwa Majumdar

  5. Center of Excellence in Space Sciences, IISER, Kolkata, 741246, India

    Dipankar Banerjee

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  1. Ritesh Patel
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Patel, R., Majumdar, S., Pant, V. et al. A Simple Radial Gradient Filter for Batch-Processing of Coronagraph Images. Sol Phys 297, 27 (2022). https://doi.org/10.1007/s11207-022-01957-y

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