Automatic detection of solar features in HSOS full-disk solar images using guided filter

Abstract A procedure is introduced for the automatic detection of solar features using full-disk solar images from Huairou Solar Observing Station (HSOS), National Astronomical Observatories of China. In image preprocessing, median filter is applied to remove the noises. Guided filter is adopted to enhance the edges of solar features and restrain the solar limb darkening, which is first introduced into the astronomical target detection. Then specific features are detected by Otsu algorithm and further threshold processing technique. Compared with other automatic detection procedures, our procedure has some advantages such as real time and reliability as well as no need of local threshold. Also, it reduces the amount of computation largely, which is benefited from the efficient guided filter algorithm. The procedure has been tested on one month sequences (December 2013) of HSOS full-disk solar images and the result shows that the number of features detected by our procedure is well consistent with the manual one.

[1]  Arnold Hanslmeier,et al.  Automatic Image Segmentation and Feature Detection in Solar Full-Disk Images , 2000 .

[2]  Dongxiao Li,et al.  Full-Image Guided Filtering for Fast Stereo Matching , 2013, IEEE Signal Processing Letters.

[3]  A. K. Pierce,et al.  Solar limb darkening , 1977 .

[4]  Xiao Yang,et al.  Automatic Recognition of Sunspots in HSOS Full-Disk Solar Images , 2016, Publications of the Astronomical Society of Australia.

[5]  E. G. Gibson,et al.  The Quiet Sun , 1973 .

[6]  Karen L. Harvey,et al.  Properties and emergence patterns of bipolar active regions , 1993 .

[7]  Dana H. Ballard,et al.  Generalizing the Hough transform to detect arbitrary shapes , 1981, Pattern Recognit..

[8]  Arnold Hanslmeier,et al.  Automatic Image Processing in the Frame of a Solar Flare Alerting System , 2000 .

[9]  M. C. Aranda,et al.  Automatic Tracking of Active Regions and Detection of Solar Flares in Solar EUV Images , 2014 .

[10]  B. R. Frieden.  Image enhancement and restoration , 1979 .

[11]  Valentina V. Zharkova,et al.  Feature Recognition in Solar Images , 2005, Artificial Intelligence Review.

[12]  K. Pearson.  Contributions to the Mathematical Theory of Evolution , 1894 .

[13]  N. Otsu.  A threshold selection method from gray level histograms , 1979 .

[14]  M. Aschwanden.  Image Processing Techniques and Feature Recognition in Solar Physics , 2010 .

[15]  Gary A. Chapman,et al.  Solar Feature Identification using Contrasts and Contiguity , 2001 .

[16]  J. Worden,et al.  Plage and Enhanced Network Indices Derived from Ca II K Spectroheliograms , 1998 .

[17]  P. Démoulin,et al.  The Magnetic Helicity Budget of a cme-Prolific Active Region , 2002 .