http://arxiv.org/abs/1911.06637
Observations of local features in the solar chromosphere began in 1992 at Huairou Solar Observing Station, while the full-disk chromosphere observations were carried out since 2000. In order to facilitate researchers to use full-disk chromosphere observation, algorithms have been developed to standardize the full-disk images. The algorithms include the determination of the center of the image and size standardization, geometric correction and intensity normalization. The solar limb of each image is determined from a histogram analysis of its intensity distribution. The center and radius are then calculated and the image is corrected for geometric distortions. Images are re-scaled to have a fixed radius of 500 pixels and centered within the 1024$\times$1024 frame. Finally, large-scale variations in intensity, such as limb-darkening, are removed using a median filter. This paper provides a detailed description of these algorithms, and a summary of the properties of these chromosheric full-disk observations to be used for further scientific investigations.
L. Suo
Mon, 18 Nov 19
32/48
Comments: 10 pages, 8 figures
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