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

20.2. CORE CALIBRATION 233
4. indark=my dark
method: Correcting with your own DARK. If you have your own DARK (obtained for
example from CAM in OP-MODE DARK) then it can be supplied to corr dark via
the keyword indark. This DARK would then used to apply correction in the normal
way.
called routine: N/A
PDS side effects: The field .DARK is filled with the DARK used for correction. The
IMAGEs in .CUBE are dark corrected, i.e. .CUBE is modified.
reference: N/A
20.2.2 Deglitching
The core calibration routine deglitch serves as an interface to all the available low-level deglitching
routines. As for the other core calibration routines, you can choose a particular deglitching
method by setting the keyword method to a particular string value. The possible values for
method and the associated deglitching methods (and the associated routines which deglitch
calls) are described in the following subsections. Technical details of some of these methods can
be found in the references given below.
1. method=‘spat’
method: Spatial and temporal deglitch. This method attempts to use both temporal
and spatial information of the .CUBE to perform deglitching. It finds the difference
between successive IMAGEs in the .CUBE – we will refer to this as the difference
image. Then it applies a thresholding criterion to each pixel of the difference image,
based on the median of the standard deviation of the difference image and the median
of the mean of the difference image. A pixel failing this criterion corresponds to a
glitch in the IMAGE.
It is considered to be a good method when the .CUBE is not stabilized. However, it
may be poor at detecting long duration or close, successive glitches.
routine called : deglitch spat
PDS side effects: Glitches removed from IMAGEs in .CUBE, i.e. .CUBE is modified.
Glitched pixels also flagged in .MASK.
reference: ISOCAM Handbook, Chapter Data processing methods, Section Spatial and
temporal deglitch.
2. method=‘temp’
method: Temporal deglitch. By this method pixels failing a combined median and standard
deviation test in temporal space are considered glitches.
This method needs a steady background level and so is not very suitable for very
unstable data.
routine called: deglitch sig
PDS side effects: Glitches removed from IMAGEs in .CUBE, i.e. .CUBE is modified.
Glitched pixels also flagged in .MASK.
reference: ISOCAM Handbook, Chapter Data processing methods, Section Temporal
deglitch.