astropy.io.fits.hdu.compressed._codecs:PLIO1

Extended Summary

The IRAF PLIO (pixel list) algorithm was developed to store integer-valued image masks in a compressed form. Such masks often have large regions of constant value hence are highly compressible. The compression algorithm used is based on run-length encoding, with the ability to dynamically follow level changes in the image, allowing a 16-bit encoding to be used regardless of the image depth.