ISIS Application Documentation
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Performs radiometric corrections on Clementine NIR images
Overview | Parameters | Example 1 |
Description
INTRODUCTION
This program performs radiometric corrections to images acquired by the Clementine spacecraft Near Infrared camera and writes the output image values in units of radiance. EQUATIONS Term1 = ( DR(x,y) - digital_offset ) / Gfact(gm) Term2 = Term1 - bias_global - BIAS(x,y) - (om * V) Term3 = Term2 / t Term4 = Term3 - DC(x,y) - 0.730 Term5 = Term4 - therm - thermShape Term6 = Term5 / FF(x,y) Term7 = Term6 / OF(x,y) Term8 = Term7 - AF(x,y) R(x,y) = Term8 * abscoef General equations applied to data for radiometric correction are indicated below: Let: x,y = line and sample position of pixel in an image R(x,y) = Result of correction in absolute radiance. DO(x,y) = Result of correction. The output can either be absolute radiance values or they can be converted to reflectance(I/F values DR(x,y) = Raw input density number FF(x,y) = Flat-field as a function of filter and line, sample position. This will be read from an ISIS cube file. OF(x,y) = Orbit dependent flat file correction. DC(x,y) = Dark current as a function of compression type, line, sample position. AF(x,y) = Empirical additive flat-field coefficients at line, sample position. BIAS(x,y) = Bias correction as a function of compression type, line, sample position. digital_offset = 9.0 bias_global = 2.0 V = -.91 abscoef = 1.0 g(GainModeID) = Gain factor as a function of insturment GainModeID g(0) = 2.0235 g(1) = 8.2755 g(2) = 4.9144 g(5) = 0.9443 g(8) = 4.1835 g(9) = 1.3530 g(11) = 15.9844 g(13) = 7.77177 g(16) = 28.1618 g(17) = 24.8658 g(18) = 21.9100 g(19) = 18.6140 g(22) = 6.83130 g(23) = 3.48425 g(24) = 20.3218 g(25) = 17.9433 g(26) = 15.8104 g(27) = 13.4320 g(28) = 9.32361 g(29) = 6.95951 g(30) = 4.75472 g(31) = 2.43896 g(33) = 13.9238 g(34) = 12.2687 g(36) = 7.23501 g(41) = 7.04438 g(42) = 6.16495 g(44) = 3.57405 g(45) = 2.73995 g(46) = 1.88595 g(48) = 11.9078 g(50) = 9.26433 g(52) = 5.39513 g(53) = 4.08125 g(61) = 1.40899 g(62) = 0.964975 gm = Gain_mode of instrument(gm = 1,2,4) om = Offset_mode of instrument(om = 1,2,3,4,...,31) t = Optimal integration duration of observation in seconds (function of ExposureDuration on labels in milliseconds.) therm = Thermal background correction value thermShape = Thermal shape correction value (always 0.0) CategoriesRelated Objects and DocumentsApplicationsHistory
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Parameter GroupsFiles
Settings
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Specify the input file to be corrected.
Type | cube |
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File Mode | input |
Filter | *.cub |
Specify the output file. The result will be the radiometrically corrected image.
Type | cube |
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File Mode | output |
Pixel Type | real |
Filter | *.cub |
This parameter allows the user to use an alternate flat-field file. In most cases, the default should be used for this parameter to indicate the derived flat-field file is to be used.
Type | cube |
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File Mode | input |
Internal Default | Automatic |
Filter | *.cub |
The parameter allows the user to use an alternate orbit dependent flat-field file. In most cases, the default should be used for this paramter.
Type | cube |
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File Mode | input |
Internal Default | Automatic |
Filter | *.cub |
The parameter allows the user to use an alternate emperical additive flat-field file. In most cases, the default should be used for this parameter.
Type | cube |
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File Mode | input |
Internal Default | Automatic |
Filter | *.cub |
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 file is to be used. The name of the derived dark current file is "$ISISDATA/clementine1/calibration/nir/dark_nir.cub" When InstrumentCompressionType = "CLEM-JPEG-0" the name of the derived dark current file is "$ISISDATA/clementine1/calibration/nir/dark_nir_cmp0.cub"
Type | cube |
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File Mode | input |
Internal Default | Automatic |
Filter | *.cub |
This parameter allows the user to use an alternate bias file. In most cases, the default should be used for this parameter to indicate the derived bias file is to be used. The name of the derived bias file is "$ISISDATA/clementine1/calibration/nir/bias_nir.cub" When InstrumentCompressionType = "CLEM-JPEG-0" the name of the derived bias file is "$ISISDATA/clementine1/calibration/nir/bias_nir_cmp0.cub"
Type | cube |
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File Mode | input |
Internal Default | Automatic |
Filter | *.cub |
This parameter allows the user to use an alternate bad pixel file. In most cases, the default should be used for this parameter to indicate the derived bad pixel file is to be used. The name of the derived bad pixel file is "$ISISDATA/clementine1/calibration/nir/badpix_nir.v3.cub" When InstrumentCompressionType = "CLEM-JPEG-0" the name of the derived bad pixel file is "$ISISDATA/clementine1/calibration/nir/badpix_nir_cmp0.v3.cub"
Type | cube |
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File Mode | input |
Internal Default | Automatic |
Filter | *.cub |
This option allows the user to decide whether to keep or remove known bad pixels. When enabled, DN values of 0.0 in the bad pixel cube are known bad pixels that will be set to NULL in the output.
Type | boolean |
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Default | true |
Apply thermal background correction
Type | boolean |
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Default | true |
DN values greater than this value in the input cube will be set to HRS.
Type | double |
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Default | 240.0 |
Example 1Calibrating a cube to radiance values using nircal Description
Calibrating a cube to radiance values using nircal
Command Line
clemnircal
nircal FROM=lna3056k.cub TO=lna3056k.cal.cub
In this example nircal will calibrate lna3056k.cub.
GUI Screenshot
Input Image
Output Image
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