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GALILEO ORBITAL OPERATIONS SOLID STATE IMAGING RAW EDR V1.0 (PDS)

NSSDCA ID: PSPG-00817

Availability: Data Identified but not Received

Description

This description was generated automatically using input from the Planetary Data System.

Data Set Overview ================= This data set has been generated by NASA's Galileo Project in order to distribute the images acquired by the Solid State Imaging (SSI) camera to the scientists and later to the Planetary Data System (PDS). This collection resides on volumes GO_0017 thru GO_0023. Included are all images of Jupiter, its satellites, stars and calibrations, acquired during the Jupiter Orbital Operations which comprise the Prime Mission, the Galileo Europa Mission (GEM), and the Galileo Millennium Mission (GMM) phases. These phases extended from June, 1996 thru March, 2002 and included SCLKs from 346405900 thru 639454500. To enhance image data return over the available spacecraft-to-Earth telecommunication channel during this phase of the mission, an Integer Cosine Transform data compressor was added as well as windowing options and multiple exposure/single read-out mode (on-chip mosaic). On-Chip-Mosaics: --------------- On-chip mosaics (OCMs) are images acquired in a multiple exposure/single read-out mode. A typical application is where four images of a target-body are acquired by slewing the camera (and stepping the filter wheel) to image the target in each of the four corners of the CCD array. CCD read-out is suppressed until all four exposures are completed, thus resulting in a 2x2 mosaic. 3x3, 5x5, or nxm mosaics are possible, where n and m are limited only by the pixel diameter of the target and pointing accuracy of the scan platform. The OCM is referred to as the parent frame. When the OCM is separated into areas, the resulting UDRs are referred to as its children. Integer Cosine Transform Compression: ------------------------------------ The Integer Cosine Transform (ICT) is a 'lossy' compression algorithm which is similar to the standard JPEG DCT (discrete cosine transform) except that it requires only integer arithmetic to implement (TONG1995). Data loss occurs during the quantization step, where frequency terms are divided by corresponding elements of an 8x8 quantization matrix. The elements of the quantization matrix can be scaled (quantization step size) to achieve greater data compression with correspondingly greater data loss. Considerable effort has been expended in designing quantization matrices with non-uniform weights to maximize data compression while minimizing data loss. In the ICT compressed mode, two windowing options are available. The image may be edited so that only an image area (called a cut-out window) is compressed and transmitted to Earth. In addition, a 96x96 pixel area within the image (called a truth window) will be transmitted with only lossless Huffman compression applied.

Parameters ========== The Galileo SSI camera acquires data in a digital raster-format containing 800 scan lines and 800 samples per scan line. Each picture element (pixel) in the two dimensional image array is represented as an 8-bit value between 0 and 255, proportional to the amount of light detected at that point (with 0 being the least amount of light and 255 being the greatest amount of light). The camera is equipped with seven color filters and a clear filter such that images taken through complementary filters can be combined during ground processing to produce color images. To make full scientific use of the image collection, the radiometric and geometric properties of the camera system should be understood. The ancillary disc, GO_0001, will provide calibration files and technical documentation necessary for the understanding of the images produced by the SSI camera. Presently, calibration files and software are available through the VICAR software system at MIPS and SPICE files are available through the Galileo Project.

Processing ========== REDR Processing: --------------- The Raw Experiment Data Records (REDRs) were produced by the Multimission Image Processing Laboratory (MIPL) at the Jet Propulsion Laboratory using several Video Image Communications and Retrieval (VICAR) programs. The processing included the following steps: --The original telemetry data was processed into raster-formatted files (GLLTELEMPROC) --Multiple versions of each data file obtained from separate downlinks or playbacks were merged together to create the best version of the data (SSIMERGE2) --The VICAR label was updated to reflect the most recent pointing information of which was acquired by updating SPICE SPK and CK data files (CATLABEL) --Bad data value information was then added to the Telemetry Header (BADLABELS) --The PDS Index table and detached PDS label files were generated. (CDGEN) --The VICAR files and PDS files were premastered onto a WORM CD-ROM which was validated. --The WORM CD-ROM was sent to a vendor and CD-ROM's were generated. --A final CD-ROM was compared bit-by-bit with the original data to ensure the quality of the vendor product. In the event that lines needed to be shifted due to CDS line dropouts or bottom partial records, the program GLLMVLN was run prior to the merging step. For on-chip mosaics, the processing steps were identical except that the program UNMOSAIC was used to extract each shutter event and output it as a separate image of the same size as the input image. (UNMOSAIC) This step is run just after the merging step. On 22 Aug. 2000, MIPS installed a new P-constants kernel, obtained from the NAIF ftp site (PCK00007.TPC, created 4/2000, replacing PCK00006.TPC, created 11/97), published in 1997 IAU report. New kernel were used to generate Orbit 27 REDR products. The only difference between the new kernel and its predecessor is in the radii of the Galilean satellites:

RA RB RC Io old 1830. 1818.7 1815.3 new 1826. 1815. 1812. Europa old 1565. 1565. 1565. new 1562. 1560. 1559. Ganymede old 2634. 2634. 2634. new 2635. 2633. 2633. Callisto old 2403. 2403. 2403. new 2409. 2409. 2409.

P-constants kernel was updated again on Mar. 05, 2001 to incorporate new planetary constants derived from calculations performed by Peter Thomas, of Cornell University, and recommedations by Ken Klaasen, from the Galileo SSI imaging team, and are based on current Galileo image data. New Kernel will be utilized to generate REDR products for orbit 28 and on up. The recent kernel changes involve the Galilean satellites' radii (RA, RB, RC) and prime meridian (PM) reference angles. RA RB RC Io old 1826. 1815. 1812. new 1829.4 1819.3 1815.7 Europa old 1563. 1560. 1559. new 1564.13 1561.23 1560.93 Ganymede old 2635. 2633. 2634. new 2632.4 2632.29 2633.35 Callisto old 2409. 2409. 2409. new 2409.4 2409.2 2409.3

PM Jupiter old ( 284.95 870.536 0. ) new ( 284.95 870.5366420 0. ) Europa old ( 35.67 101.3747235 0. ) new ( 36.022 101.3747235 0. ) Ganymede old ( 44.04 50.3176081 0. ) new ( 44.064 50.3176081 0. Callisto old ( 259.73 21.5710715 0. ) new ( 259.51 21.5710715 0. ) Metis old ( 346.09 1221.2547301 0. ) ( 355.09 1221.2547301 0. )

Multiple Playbacks/Different Compression: ---------------------------------------- In the cases where an image is played back multiple times and compression parameters vary for each playback, 'new' SCLKs are assigned with the SCLK incrementing by one minor frame each time. For example, if the image with SCLK 351000000 were played back three times with different compression parameters, the resulting SCLKs would be: 351000000 for the first playback 351000001 for the second playback at different compression 351000002 for the third playback at another compression Images from the same SCLK with different compression parameters will not be merged together.

Data ==== Each volume contains approximately 800 images stored as VICAR files. A detached PDS label has been included for each image. Documentation files have been provided which inform the user about the organization and contents of the disc, and the definition of the labels. An index files have also been provided which contain information about the images in the data set. The REDR data are generated by MIPS using procedures specifically developed or adapted for Galileo. The files are generated on a VAX and are written in VAX compatible (LSByte first) format. REDR File Format: ---------------- The Galileo REDR format was originally reserved for SSI calibration data or data which should not be radiometrically corrected. The SSI Team decided that the REDR format will be used to archive all raw SSI data.

------------------------------------------------------ | VICAR LABEL | | | ------------------------------------------------------ | BINARY HEADER | | (Telemetry Header Record & | | Bad-Data Value Header Records) | | | ------------------------------------------------------ | | | | | | | BINARY | IMAGE DATA | | PREFIX | (Pixels) | | (Line Header) | | | | | | | | | | | ------------------------------------------------------

Each REDR file will begin with a VICAR label, followed by the REDR telemetry header, and a number of bad-data value headers followed by REDR line records. Each line record will contain 200 bytes of line header information plus the pixel data (8 bits/pixel). All records have a fixed 1000-byte length within each REDR file. All formats have 1000-byte records. Note: telemetry modes with fewer than 800 lines and 800 samples occupy lines and samples of as defined in the table below (e.g., summation mode which is 400 lines and 400 samples, will occupy the first 400 lines and 400 samples of the 800 by 800 REDR). The table below lists the telemetry formats.

Telemetry Downlink # Lines X Comment Format Data Rate # Samples HIS 115.2 Kbps 400 X 400 Last 6 pixels are fill HMA 115.2 Kbps 400 X 800 Last 12 pixels are fill Sample readout: 800x800; every 2nd line has data HCA 115.2 Kbps 200 X 800 Sample readout:800x800; every 4th line has data HIM 115.2 Kbps 800 X 800 Last 12 pixels are fill IM8 806.4 Kbps 800 X 800 AI8 806.4 Kbps 400 X 400 IM4 403.2 Kbps 800 X 800

For all REDRs, the telemetry header is split into two physical records. The first 1000 bytes are placed in the first physical record after the VICAR label (the VICAR label may span more than one physical record), and the last 800 bytes are placed in the next physical record. The last 200 bytes are zero-filled. There will be a one-to-one correspondence between line records and image lines (Excluding the header records, line record 'n' will contain the data for image line 'n'). See the SSI Raw Experiment Data Record (REDR) for Phase 2 Software Interface Specification (WHITE1997) located in the DOCUMENT directory for a more detailed description of the REDR format. In addition, see the VICAR2.TXT and BADDATA.TXT files, also located in the DOCUMENT directory, and the RTLMTAB.FMT and RLINEPRX.FMT files in the LABEL directory.

Ancillary Data ============== All document files and detached label files contain a carriage return character (ASCII 13) and a line feed character (ASCII 10) at the end of each record. This allows the files to be read by the MacOS, DOS, Unix, and VMS operating systems. Tabular files are also described by a detached PDS label. The PDS label file has the same name as the data file it describes, with the extension .LBL; for example, the file IMGINDEX.TAB is accompanied by the detached label file IMGINDEX.LBL in the same directory. The detached PDS labels for REDR images contain information pertaining to the image. Tabular files are formatted so that they may be read directly into many database management systems on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks. Character fields are left justified, and numeric fields are right justified. The start byte and bytes values listed in the labels do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a normal text file on other computers.

Software ======== The following CD-ROM copy, display and processing software has been successfully tested using the Galileo SSI data: Copy Software: --DCL Exchange/network - for ascii files. --DCL COPY (VMS) - available with VMS --VICAR Copy (VMS and UNIX) - Available with VICAR package. Display Software: --NASAVIEW (PC, Apple Macintosh, UNIX) - Available from PDS. --VICAR XVD (VMS and UNIX) - Available with VICAR package --PIXEL PUSHER (Apple Macintosh) - Available from COSMIC. --NIH IMAGE (Apple Macintosh) - A public domain program available from the National Institute of Health. Processing Software: --VICAR (VMS and UNIX) - Available through the Multimission Image Processing Lab at JPL --ISIS (VMS and UNIX) - Available through the USGS in Flagstaff

Media/Format ============ Each CD-ROM disc has been formatted such that a variety of computer systems may access the data. Specifically, the discs are formatted according to the ISO 9660 level 1 Interchange Standard, and file attributes are specified by Extended Attribute Records (XARs). Formats are based on standards for archive EDR CD-ROM products established by PDS.

Data Set Overview ================= This data set has been generated by NASA's Galileo Project in order to distribute the images acquired by the Solid State Imaging (SSI) camera to the scientists and later to the Planetary Data System (PDS). This collection resides only on volume GO_0023. Included are reconstructed HIS images, acquired during Orbits 28 and 29 of the Galileo Millennium Mission phase. Please refer to hisdoc.pdf (also available in HTML format) in the DOCUMENT directory for the explanation of image anomaly and correction algorithm of the reconstructed HIS images.

Data ==== A detached PDS label has been included for each image. Documentation files have been provided which inform the user about the organization and contents of the disc, and the definition of the labels. An index file has also been provided which contains information about the images in the data set. REDR File Format: ---------------- The reconstructed HIS image has a modified REDR file format (see dataset.cat for information on PDS-compliant REDR file format). The modified HIS image file will begin with a VICAR label follow by the pixel data (8 bits/pixel). The difference between these files and the defined REDR file is that the binary information is not available. The user can refer back to the REDR data for needed information.

-------------------------------------- | VICAR LABEL | | | -------------------------------------- | | | | | IMAGE DATA | | (Pixels) | | | | | | | | | --------------------------------------

Ancillary Data ============== All document files and detached label files contain a carriage return character (ASCII 13) and a line feed character (ASCII 10) at the end of each record. This allows the files to be read by the MacOS, DOS, Unix, and VMS operating systems. Tabular files are also described by a detached PDS label. The PDS label file has the same name as the data file it describes, with the extension .LBL; for example, the file IMGINDEX.TAB is accompanied by the detached label file IMGINDEX.LBL. The detached PDS labels for REDR images contain information pertaining to the image. Tabular files are formatted so that they may be read directly into many database management systems on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks. Character fields are left justified, and numeric fields are right justified. The start byte and bytes values listed in the labels do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a normal text file on other computers.

These data are available on-line from the Planetary Data System (PDS) at: ftp://pdsimage2.wr.usgs.gov/PDS_Archive/Galileo/SSI/go_0023/

Alternate Names

  • GALILEO ORBITAL OPERATIONS SOLID STATE IMAGING RAW EDR V1.0 (PDS)
  • GO-J/JSA-SSI-2-REDR-V1.0
  • GO-J/JSA-SSI-4-REDR-V1.0

Discipline

  • Planetary Science: Geology and Geophysics

Additional Information

Spacecraft

Experiments

Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Michael J.S. BeltonData ProviderKitt Peak National Observatorybelton@jupiter.noao.edu
Dr. Amy ChenGeneral ContactNASA Jet Propulsion Laboratoryamy.c.chen@jpl.nasa.gov
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