A full-disk image standardization of the chromosphere observation at Huairou Solar Observing Station. Issue 3 (1st February 2020)

• Record Type: Journal Article
• Authors: Suo, Liu
• Is Part Of: Advances in space research. Volume 65:Issue 3(2020)
• Page Start: 1054
• Page End: 1061
• Publication Date: 2020-02-01
• Subjects: Chromosphere -- Data standardization -- Physical parameters -- Big data; Space sciences -- Periodicals; Astronautics -- Periodicals; Geophysics -- Periodicals; 500.505
• DOI: 10.1016/j.asr.2019.10.035
• Languages: English
• ISSNs: 0273-1177

Abstract

Abstract: 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 × 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 chromospheric full-disk observations to be used for further scientific investigations.