A Full-disk Image Standardization of the Chromosphere Observation at
  Huairou Solar Observing Station
  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.
