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Question #5331

Vimscal leads to poor calibration of both Jupiter and Saturn spectra.

Added by Ashwin Braude 9 months ago. Updated 6 months ago.

Status:
Acknowledged
Priority:
Normal
Assignee:
Category:
Applications
Target version:
-
Software Version:
Test Reviewer:

Description

Hi,

I am trying to calibrate a VIMS spectral image cube of Jupiter from December 2000, but the shape of the resulting calibrated spectra is very poor particularly below around 0.7um. Thinking this was just due to faulty calibration data for Jupiter (I ended up renaming the required calibration files under the RC20 directory to meet the RC19 naming guidelines), I attempted the same process using a Saturn cube, and I have found a similar result. Is there an additional stage to the calibration pipeline that I have missed, or that has to be conducted without ISIS3? I noticed in the Readme files on the PDS that there is a process to convert VIMS edrs with the prefix 'v_' to files with the prefix 'CM_' using ISIS2, but I was wondering if there was an equivalent process on ISIS3.

Find attached two files: one ('spectral_comparison_jupiter.jpg') comparing a Jupiter spectrum calibrated by me using this version of ISIS3 ('My Spectrum') with the identical spectrum calibrated by another person using an earlier version of ISIS3 ('Ideal Spectrum'), and another ('spectral_comparison_saturn.jpg') comparing a Saturn spectrum calibrated by me using ISIS3 ('My Spectrum') with an exemplary Saturn spectrum obtained from ground-based data and calibrated using different software ('Ideal Spectrum').

The steps conducted to calibrate the Jupiter cube were as follows:

vims2isis from=v1354610545_2.qub vis=v1354610545_vis.cub ir=v1354610545_ir.cub
Group = Results
VisCreated = true
IrCreated = true
End_Group
spiceinit from=v1354610545_vis.cub pck=$ISIS3DATA/cassini/kernels/pck/cpck10Jan2013.tpc [This was what I was instructed to do on a previous thread "Spiceinit on Cassini Jupiter Data"]
Group = Kernels
NaifFrameCode = -82370
LeapSecond = $base/kernels/lsk/naif0012.tls
TargetAttitudeShape = /home/braude/Isis3/isis/../data/cassini/kernels-/pck/cpck10Jan2013.tpc
TargetPosition = $base/kernels/spk/de405.bsp
InstrumentPointing = ($cassini/kernels/ck/001130_001206ra.bc,
$cassini/kernels/fk/cas_v40_usgs.tf)
Instrument = Null
SpacecraftClock = $cassini/kernels/sclk/cas00171.tsc
InstrumentPosition = $cassini/kernels/spk/010420R_SCPSE_EP1_JP83.bsp
InstrumentAddendum = $cassini/kernels/iak/vimsAddendum03.ti
ShapeModel = Null
InstrumentPositionQuality = Reconstructed
InstrumentPointingQuality = Reconstructed
CameraVersion = 1
End_Group
vimscal from=v1354610545_vis.cub to=v1354610545_vis_calib.cub
Group = Results
InputLines = 64
InputSamples = 64
StartingLine = 1
StartingSample = 1
EndingLine = 64
EndingSample = 64
LineIncrement = 1
SampleIncrement = 1
OutputLines = 64
OutputSamples = 64
End_Group

Group = Results
InputLines = 192
InputSamples = 192
StartingLine = 68
StartingSample = 65
EndingLine = 131
EndingSample = 128
LineIncrement = 1
SampleIncrement = 1
OutputLines = 64
OutputSamples = 64
End_Group

Group = Results
CalibrationVersion = RC19
SolarMultiplier = 1000.00
IR_Multiplier = 8112.34
VIS_Multiplier = 39474.13
Wave-CalMultiplier = 1000.00
OutputUnits = I/F
SolarColorFile = $cassini/calibration/vims/RC19/solar-spectrum/solar.2000_v0002.cub
Vis = true
DarkCurrentFile = $cassini/calibration/vims/vis_hires_dark_model_v0001.tab
FlatFile = $cassini/calibration/vims/flatfield/vis_hires_flatfield_v0002.cub
SpecificEnergyFile = $cassini/calibration/vims/RC19/RC19-mults/RC19.2000_v0002.cub
WavelengthCalibrationFile = $cassini/calibration/vims/RC19/wave-cal/wave.cal.2000_v0002.cub
BandwidthFile = $cassini/calibration/vims/RC19/band-wavelengths/wavelengths.2000_v0002.cub
AverageBandwidthFile = $cassini/calibration/vims/RC19/band-wavelengths/wavelengths_average_v0001.cub
End_Group

and the equivalent steps for the Saturn cube as follows:

vims2isis from=v1789445061_1.qub vis=v1789445061_1_vis.cub ir=v1789445061_1_ir.cub
Group = Results
VisCreated = true
IrCreated = true
End_Group
spiceinit from=v1789445061_1_vis.cub
Group = Kernels
NaifFrameCode = -82370
LeapSecond = $base/kernels/lsk/naif0012.tls
TargetAttitudeShape = ($base/kernels/pck/pck00009.tpc,
$cassini/kernels/pck/cpck15Dec2017.tpc)
TargetPosition = $base/kernels/spk/de405.bsp
InstrumentPointing = ($cassini/kernels/ck/14258_14263ra.bc,
$cassini/kernels/fk/cas_v40_usgs.tf)
Instrument = Null
SpacecraftClock = $cassini/kernels/sclk/cas00171.tsc
InstrumentPosition = $cassini/kernels/spk/150122R_SCPSE_14251_14283.bsp
InstrumentAddendum = $cassini/kernels/iak/vimsAddendum03.ti
ShapeModel = Null
InstrumentPositionQuality = Reconstructed
InstrumentPointingQuality = Reconstructed
CameraVersion = 1
End_Group
vimscal from=v1789445061_1_vis.cub to=v1789445061_1_vis_calib.cub
Group = Results
InputLines = 64
InputSamples = 64
StartingLine = 1
StartingSample = 1
EndingLine = 64
EndingSample = 64
LineIncrement = 1
SampleIncrement = 1
OutputLines = 64
OutputSamples = 64
End_Group

Group = Results
InputLines = 64
InputSamples = 64
StartingLine = 1
StartingSample = 1
EndingLine = 64
EndingSample = 64
LineIncrement = 1
SampleIncrement = 1
OutputLines = 64
OutputSamples = 64
End_Group

Group = Results
CalibrationVersion = RC19
SolarMultiplier = 1000.00
IR_Multiplier = 8112.34
VIS_Multiplier = 39474.13
Wave-CalMultiplier = 1000.00
OutputUnits = I/F
SolarColorFile = $cassini/calibration/vims/RC19/solar-spectrum/solar.2014_v0001.cub
Vis = true
DarkCurrentFile = $cassini/calibration/vims/vis_lowres_dark_modelv0001.tab
FlatFile = $cassini/calibration/vims/flatfield/vis_flatfield_v0002.cub
SpecificEnergyFile = $cassini/calibration/vims/RC19/RC19-mults/RC19.2014_v0001.cub
WavelengthCalibrationFile = $cassini/calibration/vims/RC19/wave-cal/wave.cal.2014_v0001.cub
BandwidthFile = $cassini/calibration/vims/RC19/band-wavelengths/wavelengths.2014_v0001.cub
AverageBandwidthFile = $cassini/calibration/vims/RC19/band-wavelengths/wavelengths_average_v0001.cub
End_Group

cat $ISISROOT/version
3.5.1.7995
2017-08-08 # Version date
v006 # 3rd party libraries version
stable # release stage (alpha, beta, stable)

Thanks,

Ashwin

spectral_comparison_jupiter.jpg View (58.5 KB) Ashwin Braude, 2018-02-14 10:35 AM

spectral_comparison_saturn.jpg View (49.5 KB) Ashwin Braude, 2018-02-14 10:35 AM

RC19_vs_RC20.png View - RC19 vs RC20 - I/F Spectral Plot (42.3 KB) Tyler Wilson, 2018-03-01 06:00 PM

RC19_vs_RC20_zoomed_in.png View - Zoomed in version two highlight the difference between the results. (45.9 KB) Tyler Wilson, 2018-03-01 06:10 PM


Related issues

Related to ISIS - Bug #4821: vimscal for Jupiter cubes no multipliers Resolved

History

#1 Updated by Ashwin Braude 9 months ago

  • Tracker changed from Bug to Question

#2 Updated by Tammy Becker 9 months ago

  • Related to Bug #4821: vimscal for Jupiter cubes no multipliers added

#3 Updated by Tammy Becker 9 months ago

  • Status changed from New to Acknowledged

#4 Updated by Tyler Wilson 9 months ago

Currently we are comparing the results from new calibration files which handle the
spectral drift, and comparing them to the calibration pipeline at the University of Arizona.
I am not certain yet if these calibration files will solve the issues you are seeing
but adding to the documentation to make it clear where the calibration files work are and are not
working is something which I will do when the the verification is finished.

I will calibrate the cubes you were having problems with using our updated calibration files,
and attach the results to this ticket sometime this weekend so we can compare them.

Thank you for bringing this issue to our attention.

%\%\%\%\%\%\%\%\%\%\%\%\
Tyler Wilson
Computer Scientist
U.S. Geological Survey
Astrogeology Science Center
2255 N. Gemini Drive
Flagstaff, AZ 86001
Office: (928) 556-7356
Fax: (928) 556-7014
tjwilson@usgs.gov
http://astrogeology.usgs.gov/
\%\%\%\%\%\%\%\%\%\%\%\%\

#5 Updated by Ashwin Braude 9 months ago

Hi,

Any luck with the new calibration files?

Thanks,
Ashwin

#6 Updated by Tyler Wilson 9 months ago

Hello Ashwin,

I'm still working on it. My apologies for not getting back to you sooner.
I will give you an update tomorrow.

--
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Tyler Wilson
Computer Scientist
U.S. Geological Survey
Astrogeology Science Center
2255 N. Gemini Drive
Flagstaff, AZ 86001
Office: (928) 556-7356
Fax: (928) 556-7014
tjwilson@usgs.gov
http://astrogeology.usgs.gov/

\%\%\%\%\%\%\%\%\%\%\%\%\

#7 Updated by Ashwin Braude 9 months ago

Tyler Wilson wrote:

Hello Ashwin,

I'm still working on it. My apologies for not getting back to you sooner.
I will give you an update tomorrow.

--
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Tyler Wilson
Computer Scientist
U.S. Geological Survey
Astrogeology Science Center
2255 N. Gemini Drive
Flagstaff, AZ 86001
Office: (928) 556-7356
Fax: (928) 556-7014
tjwilson@usgs.gov
http://astrogeology.usgs.gov/

Ok that's fine, thank you for doing this!

Ashwin

#8 Updated by Tyler Wilson 9 months ago

Hi Ashwin,

I was able to SPICE initialize the second cube you gave me but not the first one.
I noticed it was from 2000, and at present we do not have kernels for the
Jupiter fly-by at that point in the mission. This impacts upon my task of verifying the calibration
files for the end-of-mission are correct, so I will need to get those kernels from NAIF.

For the Saturn cub, attached please find a spectral plot comparing the results using RC19 calibration files and RC20 files at (Or approximately near Sample 28, Line 28 in the image space). This appears to match very closely with your result (although I would need to know what Line/Sample you were at in the image). The difference between RC19 and RC20 calibration files appear to be quite close. I would be interested to know how the other curve in your plot was generated using what software, and whether or not it accounted for spectral drift. Spectral drift showed up very early in the mission, and was most extreme and volatile during the early part of the mission before settling down to a semi-stable curve. The RC19 files were the first files to account for this, and the RC20 files are updated versions of RC19 we received from the mission team after the mission had ended.

Below is the output from my print.prt file when I ran vimscal using the new calibration files:

Object = vimscal
  IsisVersion       = "3.5.2.0 beta | 2017-11-04"
  ProgramVersion    = 2017-01-03
  ProgramPath       = /work/users/tjwilson/vimscal/isis/bin
  ExecutionDateTime = 2018-03-01T17:41:14
  HostName          = pinto
  UserName          = tjwilson
  Description       = "Radiometric correction of Cassini VIMS camera images."

  Group = UserParameters
    FROM        = v1789445061.vis.cub
    TO          = v1789445061.vis.RC20.cub
    UNITS       = IOF
    FLATFIELD   = 2006FLAT
    IRORIGDARK  = false
    DARK        = true
    CALIBRATION = RC20
  End_Group

  Group = Results
    InputLines      = 64
    InputSamples    = 64
    StartingLine    = 1
    StartingSample  = 1
    EndingLine      = 64
    EndingSample    = 64
    LineIncrement   = 1
    SampleIncrement = 1
    OutputLines     = 64
    OutputSamples   = 64
  End_Group

  Group = Results
    InputLines      = 64
    InputSamples    = 64
    StartingLine    = 1
    StartingSample  = 1
    EndingLine      = 64
    EndingSample    = 64
    LineIncrement   = 1
    SampleIncrement = 1
    OutputLines     = 64
    OutputSamples   = 64
  End_Group

  Group = Results
    CalibrationVersion        = RC20
    SolarMultiplier           = 1000.00
    IR_Multiplier             = 8112.34
    VIS_Multiplier            = 39474.13
    Wave-CalMultiplier        = 1000.00
    OutputUnits               = I/F
    SolarColorFile            = $cassini/calibration/vims/RC20/solar-spectrum-
                                /VIMS2014.5000.solar_v0002.cub
    Vis                       = true
    DarkCurrentFile           = $cassini/calibration/vims/vis_lowres_dark_mod-
                                el_v0001.tab
    FlatFile                  = $cassini/calibration/vims/flatfield/vis_flatf-
                                ield_v0002.cub
    SpecificEnergyFile        = $cassini/calibration/vims/RC20/RC19-mults/VIM-
                                S2014.5000.calibration.multiplier.RC19_v0002.-
                                cub
    WavelengthCalibrationFile = $cassini/calibration/vims/RC20/wave-cal/VIMS2-
                                014.5000.wave-photon-cal_v0002.cub
    BandwidthFile             = $cassini/calibration/vims/RC20/band-wavelengt-
                                hs/VIMS2014.5000.wavelengths_v0002.cub
    AverageBandwidthFile      = $cassini/calibration/vims/RC20/band-wavelengt-
                                hs/VIMS.wavelengths.average_v0002.cub
  End_Group

  Group = Accounting
    ConnectTime = 00:00:00.1
    CpuTime     = 00:00:00.1
  End_Group
End_Object

If you have any more questions, I would recommend emailing me directly. I'll be updating this
ticket when I get the updated SPICE kernels, but I was trying to attach a space-delimited .txt file of the table comparing the different calibration files, and the bug-tracking software we use wouldn't let me do that.

==Tyler

--
\%\%\%\%\%\%\%\%\%\%\%\%\

Tyler Wilson
Computer Scientist
U.S. Geological Survey
Astrogeology Science Center
2255 N. Gemini Drive
Flagstaff, AZ 86001
Office: (928) 556-7356
Fax: (928) 556-7014
tjwilson@usgs.gov
http://astrogeology.usgs.gov/

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#9 Updated by Makayla Shepherd 6 months ago

  • Assignee set to Tyler Wilson

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