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Paper: Optimal Compression of Floating-Point FITS Images
Monograph: 6, Twenty Years of ADASS
Page: 225
Authors:
Abstract: Lossless compression (e.g., with GZIP) of floating-point format astronomical FITS images is ineffective and typically only reduces the file size by 10% to 30%. We describe a much more effective compression method that is supported by the publicly available fpack and funpack FITS image compression utilities that can compress floating point images by a fact of 10 without loss of significant scientific precision. A “subtractive dithering” technique is described which permits coarser quantization (and thus higher compression) than is possible with simple scaling methods.
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