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ISIS Documentation

mar10cal

Radiometrically calibrates a Mariner10 image

mar10cal performs radiometric corrections to images acquired by the Mariner 10 vidicon cameras. MAR10CAL performs a dark curent correction and linearization of Mariner 10 images. Key documents to refer to: MVM 73 TV Subsystem Calibration Report, M. Benesh and M. Morrill, JPL 615-148, 1973. Acquisition and Description of Mariner 10 Television Science Data at Mercury, G.E. Danielson, K.P. Klaasen, J.L. Anderson, Jour. Geophys. Research, Vol. 80, No. 17, pp 2357-2393, 1975 (and other articles in this issue). It should be noted that the flat field and sensitivity fluctuates as a function of vidicon temperature (especially for camera A). The camera heater was not functioning during encounters 2 and 3 and thus these encounters use a different calibration than the 1st encounter. Reliable non-linearity correction is thus available only for encounter 1 images. CAUTION: the program will process the encounter 2 and 3 images but the results are not reliable for any quantitative applications such as albedo measurements (absolute or relative) or photoclinometry. The situation is not hopeless, much effort has gone into deriving a fix for the 2nd and 3rd encounter frames and a future update of mar10cal will incorporate this work.

Categories

History

Mark Robinson1991-09-18 Original version
Tracie Sucharski2009-04-15 Converted to Isis Isis2 Change History: Oct 25 1991 - Tammy Becker, USGS,Flagstaff, Converted to DOIO and TAE Mar 01 1995 Tracie Sucharski, Converted to ISIS/UNIX Nov 21 1995 Tracie Sucharski, Changed name of coefficient file Feb 08 1996 Tracie Sucharski, Print name of calibration files used to terminal and print.prt. Mar 05 1996 Tracie Sucharski, Added blemish removal option Mar 29 1996 TLS, New and improved equation Apr 23 1996 TLS, Added user parameter of EXPOFF, also bomb neatly if EXPOSURE on labels is 0. Apr 29 1996 TLS, Added new RFFCOEF values. May 02 1996 TLS, Added user parameter ABSCOEF May 03 1996 TLS, Changed name of WAVECOEF to RFFCOEF(Relative Filter Factor Coefficient) May 16 1996 TLS, Get rid of Relative Filter Factor, corrected abscoef values. May 17 1996 TLS, Add new dark current files. May 28 1996 TLS, If input pixel - dark current is <, set output pixel to NULL. Also add new coefficient file.
Travis Addair2010-09-03 First commit, added exception handling, finished conversion.
Travis Addair2010-09-20 Fixed minor process inconsistencies with Isis 2, clean up code, added tests.

Parameters

Files

An uncalibrated Mariner 10 image.
Type cube
File Mode input
Filter *.cub

The resultant radiometrically calibrated cube
Type cube
File Mode output
Pixel Type real

A cube file containing the calibration coefficients. This file should have eight bands, bands 1-4 are the coefficients for inverting the third order equation, bands 5-6 are the minimum and maximum values to process. Bands 5-6 are only used if the MASK parameter is set to "YES". If MASK is set, pixels with values outside of this range are set to NULL in the output. The mask assures that only pixels with dns in the range of the prelaunch fit are calibrated, dns outside this range are interpolations and may contain large errors. In most cases the default should be used and the files derived from the prelaunch calibration flat fields will be used. These files are named - $ISISMAR10DATA/mariner_10_"First 3 letters of FILTER_NAME"_ "INSTRUMENT_ID"_coef.cub. See also 1) Robinson et al., Jour. Geophys. Res., 97, p.18265-18274, 1992. 2) Robinson and Lucey, Science, 275, p. 197-200, 1997. 3) Robinson et al., abstracts of Lunar Planetary Sci. Conf. XXVIII, p. 1187-1188, Lunar and Planetary Inst, Houston, TX, 1997.

Type cube
File Mode input
Pixel Type real
Internal Default Internal Default

This parameter allows the user to use an alternate dark current file. In most cases, the default should be used for this parameter to indicate the derived dark current file is to be used. The name of the derived dark current file is $ISISDATA/mariner10//mariner_10_"InstrumentId"_dc.cub. The InstrumentId wil have a value of "A" or "B".
Type cube
File Mode input
Pixel Type real
Internal Default Internal Default

Calibration Parameters

If TRUE, bands 5-6 of the coefficient cube are the minimum and maximum values to process. Any values outside of this range are set to NULL in the output file. Caution should be used in setting MASK to FALSE - the resulting dns may have less than optimal radiometric integrity.
Type boolean
Default True

Apply blemish removal mask.
Type boolean
Default True

Approximation for iterative solution.
Type double
Default 75.0

After dark removal and linearity correction an absolute coefficent needs to be applied to put the data in units of radiance. These coefficents (1 for each camera-filter combination) are still being refined. The values are being derived by forcing global mosaics (photometrically corrected) to Earth based measurements. for futher explanation see; 1) Robinson and Lucey, Science, 275, p. 197-200. 2) Robinson et al., abstract of Lunar Planetary Sci. Conf. XXVIII, p. 1187-1188, 1997.

Type double
Internal Default Internal Default

Offset to be added to Exposure time. If the default of NULL is used the following values are added to the offset: Camera A EXPOFF = 0.316 msecs Camera B EXPOFF = 3.060 msecs These values are taken directly from the Benesh and Morrill JPL calibration document. They state that there are some unknowns with these values... Read the section on their page 38.

Type double
Internal Default Camera A = 0.316 msec Camera B = 3.060 msec