| 22 Nov 2011 06:59 AM |
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Hello,
I'm performing the the Landsat calibration to radiance/reflectance (basic tools --> preprocessing).
Some parameters are obligatory to fill in: sensor type, date, sun elevation and band. Then, ENVI uses default values for the calibration parameters Lmin, Lmax, gain and bias. But these default values don't seem to be accurate if I compare the Lmin/Lmax with those in the MTL file and if I calculate the gain/bias myself.
So I suppose that the result is more accurate when the calibration parameters are filled in for each scene.
Thanks!
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MariM
Veteran Member
Posts:2396  
| 22 Nov 2011 07:11 AM |
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Are you using ENVI 4.7 or 4.8? The Landsat calibration tool was updated for 4.7 and you should use this version to get accurate results.
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Deleted User
New Member
Posts: 
| 22 Nov 2011 07:51 AM |
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I'm using ENVI 4.7. But if I specify the parameters myself, the results should be ok?
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MariM
Veteran Member
Posts:2396
| 22 Nov 2011 07:54 AM |
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Yes it should be ok to do that. That is why the dialog allows it. But if you open your Landsat as "Geotiff with metadata" then these dialogs should populate automatically with the values from the MTL.
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Deleted User
New Member
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| 22 Nov 2011 08:53 AM |
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Ok, thanks. The.TIF files and the MTL file are opened in the band list, but one band in the Calibration tools doesn't give accurate results. How do populate the MTL values?
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MariM
Veteran Member
Posts:2396
| 22 Nov 2011 09:03 AM |
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I don't understand. If you open your file using File ->Open External Format ->Landsat->Landsat with metadata, then when you use the Landsat calibration tool, the values are automatically populated. The LMIN/LMAX come from the metadata file and you can change them if you like by selecting 'Edit Calibration Parameters'.
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