stara#

sunkit_image.stara.stara(smap, circle_radius: Unit("deg") = <Quantity 100. arcsec>, median_box: Unit("deg") = <Quantity 10. arcsec>, threshold=6000, limb_filter: Unit("%") = None)[source]#

A method for automatically detecting sunspots in white-light data using morphological operations.

Parameters:

  • smap (sunpy.map.GenericMap) – The map to apply the algorithm to.

  • circle_radius (astropy.units.Quantity, optional) – The angular size of the structuring element used in the skimage.morphology.white_tophat. This is the maximum radius of detected features. By default, this is set to 100 arcseconds.

  • median_box (astropy.units.Quantity, optional) – The size of the structuring element for the median filter, features smaller than this will be averaged out. The default value is 10 arcseconds.

  • threshold (int, optional) – The threshold used for detection, this will be subject to detector degradation. The default value of 6000, is a reasonable value for HMI continuum images.

  • limb_filter (astropy.units.Quantity, optional) – If set, ignore features close to the limb within a percentage of the radius of the disk. A value of 10% generally filters out false detections around the limb with HMI continuum images.

Returns:

numpy.ndarray – A 2D boolean array of the same shape as the input solar map. Each element in the array represents a pixel in the solar map, and its value is True if the corresponding pixel is identified as part of a sunspot (based on the specified threshold), and False otherwise.

References

  • Fraser Watson and Fletcher Lyndsay “Automated sunspot detection and the evolution of sunspot magnetic fields during solar cycle 23” Proceedings of the International Astronomical Union, vol. 6, no. S273, pp. 51-55, 2010. (doi:10.1017/S1743921311014992)[https://doi.org/10.1017/S1743921311014992]

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