On-board lossless compression of solar corona images
The compression algorithm developed for METIS arises from the standard CCSDS 123.0-r-1 [1], a lossless data compressor suitable for multispectral and hyperspectral imagers and sounders. This paper presents an extension of the standard to handle lossless compression specifically tailored to solar corona images. The main contributions of this paper are the following: the adaptation to the radial geometry of solar corona images through a remapping process called “radialization” and the ability to exploit three-dimensional image compression of the standard through the compression of a multi-temporal data cube composed by successive acquisitions. The development of the algorithm took care of many aspects based on the geometry and the nature of the expected acquisitions; this adaptation process leads to a significant increase in compression performance through routines resulting very light from a computational point of view, which is a key aspect for on-board applications.