Changes between Version 1 and Version 2 of Sensors/Fodis


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Timestamp:
Feb 14, 2012 12:27:09 PM (8 years ago)
Author:
mark1
Comment:

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  • Sensors/Fodis

    v1 v2  
    99DCALM's downwelling light collector (prior to cleaning!) mounted on the roof:
    1010
    11 [[Image(wiki:Processing/FODIS:dcalm_fodis_collector.jpg)]]
     11[[Image(wiki:Processing/FODIS:dcalm_fodis_collector.jpg)]] 
    1212
    1313Side view of DCALM, showing location of downwelling light collector:
    1414
    1515[[Image(wiki:Processing/FODIS:dcalm_side_view.jpg)]]
     16
     17== Processing ==
     18
     19=== 2011 onwards ===
     20
     21The FODIS data processing (2011 onwards) is much the same as for the Eagle data except that each scan line of FODIS data (4 pixels) is averaged together to reduce noise. The resulting processed data will consist of 1 data value per scan line of imagery.
     22
     23=== pre-2011 ===
     24
     25Details on processing the pre-2011 ILS/FODIS data are in the azgcorr manual (to a limited extent - we'll improve this as soon as we get the manual text..). Basically it's an extra data vector in the HDF files, called CAils, with one pixel of upwards-looking data per downwards-looking scanline.
     26
     27The vector should be present in all CASI and Eagle HDFs, but will be garbage in any flight where the sensor wasn't connected (fibre optic cable from the CCD to the roof-mounted collector). If the data are correct, they should resemble the solar spectrum.
     28
     29It will also be garbage in any Eagle HDFs preceding mid 2008 as the cable wasn't connected (may be present in some Ethiopia flights) and the processing wasn't working (fixed as of June/08, backprocessing available on request).
     30
     31Note that due to a bug in ENVI (?), it appears that one gets odd spiky results from directly viewing the HDF vector. You must extract it first with:
     32{{{
     33azexhdf -Be fodis.bil -d CAils youreagle.hdf
     34}}}