ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

100 CHAPTER 13. DATA CALIBRATION
13.2 Calibrating the PDS
So you have your PDS created and want to calibrate it. There is a core set of CIA calibration
routines that perform corrections which are required for all CAM data regardless of AOT, e.g.
dark correction, deglitching, stabilization, flat-fielding. These routines are described in the
Section 13.2.1. Further sections describe routines that perform AOT dedicated processing, e.g.
raster MOSAIC creation. So to do a complete calibration of your data first read Section 13.2.1
followed by one of Sections 13.2.2, 13.2.4 or 13.2.5 depending on the flavour of your PDS.
13.2.1 Core calibration
The first three core calibration routines that we will meet are corr dark, deglitch and stabilize.
These routines perform the following core corrections: (i) dark correction, (ii) deglitching,
(iii) stabilization. All have a choice of different methods, though for simplicity we will just use
the default here. Though we use a raster PDS in our example below, these routines accept any
flavour of PDS as input.
1. Following from Section 13.1.2 we will restore our previously saved raster PDS and perform
the first calibration steps on the IMAGEs in lw6 raster.cube.
CIA> restore, ’lw6_raster.dat’, /verb
CIA> corr_dark, lw6_raster
CIA> deglitch, lw6_raster
CIA> stabilize, lw6_raster
2. We can look at the results of our processing so far by viewing the the corrected IMAGEs
in lw6 raster.cube with x3d.
CIA> x3d, lw6_raster
Clicking on the button mask indicates the pixels that have been masked as unstable. By
looking at the temporal history of the pixels you can immediately see if good stabilisation
and deglitching have been achieved. A vertical profile of some background pixels will tell
you if a good dark correction has been applied.
3. Now can proceed with flat-fielding. Firstly, all the IMAGEs per CAM pointing /SCD must
be averaged to EXPOSUREs – the routine reduce does just that. Then the flat-fielding
is performed on each EXPOSURE with corr flat.
CIA> reduce, lw6_raster
CIA> corr_flat, lw6_raster
Now we have completed the final processing step with the core calibration routines.