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Proceedings Paper

Scientific data compression for space: a modified block truncation coding algorithm
Author(s): Wei-Wei Lu; Michael Paul Gough; Peter N. H. Davies
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Paper Abstract

Satellite science experiments generate a great amount of on-board data. This must be compressed before transmission due to the limited telemetry channel capacity. But the data are essentially random and thus difficult to compress efficiently. This paper presents a modified block truncation coding (MBTC) algorithm for image data compression, especially applicable to scientific data compression, in which the science information should be preserved. The new algorithm has the following new features: (1) optimal quantization--the block truncation coding (BTC) quantizer is replaced by a Lloyd optimal quantizer; (2) differential coding--the differences of pixels of adjoining scan lines (rather than the amplitudes of pixels) are quantized; (3) entropy coding--the quantized outputs are encoded by means of the entropy coding method; and (4) error control--this is included to generate the reconstructed images in which no error is greater than a preset threshold. Simulation results are presented for the compression of satellite geophysical data which are similar to image data. It is shown that the new algorithm, MBTC, is able to maintain many details of the original data and performs better than BTC in terms of: reducing mean-square error MSE (see appendix), increasing compression ratio R (see appendix) and generating a better visual quality of the reconstructed images. The techniques used here are especially applicable to space-acquired science data because (1) the on-board computational requirements are low, and (2) the scientific data information content is maintained. Further improvements to the MBTC are also discussed.

Paper Details

Date Published: 1 August 1991
PDF: 9 pages
Proc. SPIE 1470, Data Structures and Target Classification, (1 August 1991); doi: 10.1117/12.44851
Show Author Affiliations
Wei-Wei Lu, Univ. of Sussex (United Kingdom)
Michael Paul Gough, Univ. of Sussex (United Kingdom)
Peter N. H. Davies, Univ. of Sussex (United Kingdom)


Published in SPIE Proceedings Vol. 1470:
Data Structures and Target Classification
Vibeke Libby, Editor(s)

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