Charters : 5.03 Data Compression Working Group

 

Future space missions will make increasing use of multispectral and hyperspectral imagers and other instruments, that significantly increase the volume of data to be collected and transmitted to the ground. Cooperative mission scenarios exist where cross-support is needed for handling the resulting increased data volume. Industry, principal investigators, instrument developers, etc., will welcome international standards for compression of these data types to meet the unique requirements of space missions and provide state-of-the-art performance levels.

Implementation constraints severely limit the complexity of on-board processing. Existing standard approaches to compression of multispectral and hyperspectral data (e.g., JP3D, an existing 3D extension to the JPEG2000 standard) have high implementation complexity as they have not been optimized with respect to performance-complexity tradeoff for space applications. Current CCSDS data compression recommendations 121.0-B-1 and 122.0-B-1 have lower complexity and can be applied to multi- and hyperspectral data, but offer substantially less effective compression than modern compression algorithms designed specifically for multi- and hyperspectral image data. Therefore, it is the consensus of the participating agencies that the development of new recommendations for compression of multispectral and hyperspectral image data and other data types is necessary together with regular "maintenance" of existing books.

The Working Group goals shall be achieved by updating the existing set of Data Compression Books by either modifying existing books or creating new books as required and described in the WG Projects.

The goals of the Multispectral and Hyperspectral Data Compression Working Group are to:

1. Finalize selection criteria and requirements matrix for compression standard(s) for lossless and lossy compression of multispectral and hyperspectral imager data.  Criterion will include implementation complexity as well as quantitative quality criteria to evaluate lossy compression effectiveness.

2. Establish a set of test data (including, when available, ground truth data for a relevant application) for testing and evaluation of candidate compression algorithms.

3. Evaluate candidate algorithms using the selection criteria established and considering the needs of the CCSDS member agencies.

4. Develop a recommendation together with supporting information (simulation software, test data sets, and Green Book).

5. Develop Recommended Standard for Compression of Housekeeping Data.

6. Develop Recommended Standard for Compression of Synthetic Aperture Radar (SAR) Data.

See individual projects.

There is a possibility that no single algorithm will suit all of the agency needs given the diversity of sensors and mission constraints.

The resource commitments significantly leverage previous and ongoing data compression work efforts.  However, increased resource commitments will likely be necessary in future years for timely completion of a recommendation.