  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.
