PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "2005-12-11, P. Cavender corrected syntax; 2006-09-18, MRO CRISM:HWT line length fix; 2006-10-23, S. Murchie, model update" DATA_SET_ID = "MRO-M-CRISM-4/6-CDR-V1.0" /* The time string in the product ID will increment when new wavelength */ /* filter tables or pixel processing tables commence usage in the instrument*/ PRODUCT_ID = "CDR6_2_0835291663_CP_S_0" PRODUCT_TYPE = CDR SPACECRAFT_ID = MRO INSTRUMENT_ID = CRISM /* The start time field will increment when new wavelength */ /* filter tables or pixel processing tables commence usage in the instrument*/ START_TIME = 2006-06-20T17:27:43 STOP_TIME = NULL /* The start clock count field will increment when new wavelength */ /* filter tables or pixel processing tables commence usage in the instrument*/ SPACECRAFT_CLOCK_START_COUNT = "2/835291663" SPACECRAFT_CLOCK_STOP_COUNT = NULL /* The creation time field will increment when new wavelength */ /* filter tables or pixel processing tables commence usage in the instrument*/ /* or when a new version is issued */ PRODUCT_CREATION_TIME = 2005-10-23T14:00:00 MRO:SENSOR_ID = "S" PRODUCT_VERSION_ID = "0" /* CRISM VNIR Data Compressibility File */ /* */ /* The purpose of this file to provide estimates of the compressibility of */ /* data taken with the IR detector. */ /* */ /* Data compression in CRISM occurs in several stages. The first set of */ /* steps is reformatting of the data, or data editing. Data are read off */ /* the detector as unsigned 14-bit integers. The data are converted to */ /* unsigned 12-bit integers by subtracting an offset and multiplying by a */ /* gain, which can be uploaded to the instrument. The current values of */ /* gain and offset at the time of creation of this file are reported in the */ /* file CDR6_0000000000_PP_S_1.TAB or by the most current version covering */ /* the same time span. The offset subtraction and gain multiplication */ /* always occur, and are needed to prepare data for processing by the DPU. */ /* Next, optionally, pixels may be binned 2x, 5x, or 10x in the spatial */ /* (column) direction. Whether and how this is done is controlled by */ /* command. Next, selected rows (wavelengths) of data are retained for */ /* further processing by the DPU. For each detector there is a menu of four */ /* tables (0-3), which can be uploaded to the instrument. The current */ /* values in the wavelength table are reported in the file */ /* CDR6_0000000000_WV_S_1.TAB or by the most current version covering the */ /* same time span. Which of the tables are used is controlled by command; */ /* one table is always used. */ /* */ /* The next set of two steps includes those whose effects on data volume */ /* are tabulated in this file. The first step is lossy compression. */ /* Optionally the 12-bit unsigned integer may be replaced with an 8-bit */ /* unsigned integer using a lookup table. There are 8 lookup tables hard */ /* coded in the instrument, whose conversions are tabulated in */ /* CDR6_0000000000_LK_J_0.TAB. The usage of lossy compression is */ /* controlled by command. Which lookup tables are used for each row of the */ /* detector are uploadable to the instrument. The current values at the */ /* time of creation of this file are reported in the file */ /* CDR6_0000000000_PP_S_1.TAB or by the most current version covering the */ /* same time span. The second step is lossless compression using the Fast */ /* algorithm, whose usage is controlled by command. */ /* */ /* The compression ratios reported here include only the effects of lossy */ /* and lossless compression. That, is, for a given type of data, a current */ /* set of values in CDR6_0000000000_PP_S_1.TAB, a current set of values in */ /* CDR6_0000000000_WV_S_1.TAB, and a given pixel binning, what is the ratio */ /* of uncompressed to compressed data volume using either or both lossy and */ /* lossless compression. The image frames are compressed but their headers */ /* are not, and this is accounted for. */ /* */ /* The types of data being compressed relate to the field MRO:ACTIVITY_ID */ /* in each EDR label. If the data come from the detector, they may */ /* represent a shutter-closed dark measurement (DF), a series of dark */ /* measurements used to estimate image bias (BI), a measurement of a focal */ /* plane lamp (LP), a measurement of the onboard integrating sphere (SP), */ /* or a measurement of a scene (SC). Alternatively the focal plane */ /* electronics may issue one of seven test patterns (activity T1 through */ /* T7). A special case occurs when data acquisition is commanded without */ /* the focal plane powered. In that case a DPU test pattern takes the place */ /* of values from the detector or focal plane electronics. The case is */ /* expected to occur during ground testing of CRISM sequences of the MRO */ /* orbiter test-bed. The compressibility of test pattern data was */ /* determined by calculation, whereas the compressibility of detector data */ /* was determined by analysis of onground calibrations. */ OBJECT = FILE /* The time string in the file name will increment when new wavelength */ /* filter tables or pixel processing tables commence usage in the instrument*/ ^TABLE = "CDR6_2_0835291663_CP_S_0.TAB" RECORD_TYPE = FIXED_LENGTH FILE_RECORDS = 640 OBJECT = TABLE NAME = "CRISM VNIR DATA COMPRESSIBILITY FILE" INTERCHANGE_FORMAT = "ASCII" ROWS = 640 COLUMNS = 7 ROW_BYTES = 535 DESCRIPTION = "CRISM VNIR Data Compressibility File " OBJECT = COLUMN COLUMN_NUMBER = 1 NAME = ACTIVITY_TYPES DATA_TYPE = CHARACTER START_BYTE = 1 BYTES = 6 DESCRIPTION = "The types of activity having the compression ratio for the indicated combination of wavelength filter, binning, lossy compression, and lossless compression. DFBI includes a shutter-closed dark measurement (activity DF), or a series of dark measurements used to estimate image bias (activity BI). LPSPSC includes a measurement of a focal plane lamp (activity LP), a measurement of the onboard integrating sphere (SP), or a measurement of a scene (SC). OT is the DPU test pattern. T1 through T7 are the 1st through 7th test patterns generated in the focal plane electronics." END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 2 NAME = FILTER DATA_TYPE = ASCII_INTEGER START_BYTE = 8 BYTES = 1 DESCRIPTION = "Wavelength filter table; which of uploadable tables 0-3; specified separately for each detector" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 3 NAME = BINNING DATA_TYPE = ASCII_INTEGER START_BYTE = 10 BYTES = 1 DESCRIPTION = "Spatial pixel binning mode; specified separately for each detector; 0 = 1:1; 1 = 2:1; 2 = 5:1; 3 = 10:1" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 4 NAME = LOSSY DATA_TYPE = ASCII_INTEGER START_BYTE = 12 BYTES = 1 DESCRIPTION = "Lossy compression enabled or disabled; 12 to 8 bit look-up table commanded line by line in uploaded data structure; specified separately for each detector; 0 = disabled; 1 = enabled" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 5 NAME = FAST DATA_TYPE = ASCII_INTEGER START_BYTE = 14 BYTES = 1 DESCRIPTION = "Lossless Fast compression enabled or disabled; specified separately for each detector; 0 = disabled; 1 = enabled" END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 6 NAME = COMPRESSION_RATIO DATA_TYPE = ASCII_REAL START_BYTE = 16 BYTES = 6 DESCRIPTION = "Ratio of uncompressed to compressed data volume with lossy and Fast applied as indicated." END_OBJECT = COLUMN OBJECT = COLUMN COLUMN_NUMBER = 7 NAME = COMMENT DATA_TYPE = CHARACTER START_BYTE = 23 BYTES = 512 DESCRIPTION = "Description of method by which compression ratio was derived." END_OBJECT = COLUMN END_OBJECT = TABLE END_OBJECT = FILE END