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+--- Thread: ATCOR with MASTER data (/showthread.php?tid=58)
ATCOR with MASTER data - rese_support - 08-Oct-2014
jgrn
jgrn@illinois.edu
128.174.120.152
Hi there -- I'm trying to calibrate MASTER data with ATCOR and have not successfully gotten it working yet. The output looks like its all flat. My first suspicion is the .cal file that comes with ATCOR is not right for my particular acquisition, but where in the HDF file are the calibration coefficients?--jonathan
Re: ATCOR with MASTER data
admin
daniel@rese.ch
194.209.88.154
The documentation of MASTER on http://mas.arc.nasa.gov/reference/guide.html tells us that:Radiance = (Count - (Gain * CBBavg)) * Slope  [W/(m2 sr micron)] which is Radiance = Count*Slope - Gain*CBBavg*SlopeIn ATCOR conventions this should be: Radiance = Count * c1 + c0 [mW/(cm2 sr micron)]with 1 [mW/(cm2 sr micron)] = 10 [W/(m2 sr micron)]i.e. c1= Slope / 10c0= - Gain*CBBavg*Slope /10this needs to be calculated for each spectral bands. .. hope this helps.Also make sure that the response files are read in appropriately. Daniel
Daniel:Follow-up on this. I spoke to NASA and here's the low-down with MASTER data -- the HDF contains an already-calibrated radiance cube. The HDF file contains scaling parameters that are, depending on the software, automatically applied to the image stack. If not, those scaling parameters do need to be extracted from the HDF file (they do not appear elsewhere, as far as I can tell, in the metadata). As mentioned above, you then need to divide them by 10 to get the right units.If you are using ENVI, and you open the file as Thermal-> MASTER, ENVI auto-applies the scaling factors (which can then be saved out as a BSQ). On the other hand, if you open it as a generic HDF, the scaling factors will NOT be auto-applied.If you were to make an import filter for MASTER, as far as I can tell you can ignore equation you listed -- those have already been applied to the MASTER data. Thus, you need to extract from the HDF the image cube and its scaling factors.