Name
jitter - isaac/sofi jitter imaging reduction
Synopsis
jitter [flags] [options]
Description
jitter reduces images taken in infrared jitter imaging
mode. It makes a number of assumptions on the input signal
and has a list of several possible algorithms with associ-
ated parameters for each reduction stage.
jitter has been developped to reduce jitter imaging data
taken from infrared instruments, e.g. IRAC2, SOFI, or
ISAAC. Although some features are specific to the two lat-
ter instruments, it is reasonable to think that the same
algorithms should work on similar data.
jitter is configured through an initialization file. The
name of this file is defaulted to jitter.ini but can be
changed through the use of the -f option. In the following
documentation, this file is referred to as the ini file.
Process
The jitter data reduction process is divided into flat-
fielding/dark subtraction/bad pixel correction, sky esti-
mation and subtraction, frame offset detection, frame re-
centering, frame stacking to a single frame, and optional
post-processing tasks. Some processes may be deactivated
depending on what you intend to do with the data. Describ-
ing all the algorithms in this command is far beyond the
scope of this manual page. A documentation about the jit-
ter algorithm can be found on the eclipse web site, a copy
of this paper will be included in the doc directory in a
future release.
To setup the process, you need first to generate a default
jitter.ini file and then change parameters according to
your needs. This initialization file is self-documented.
Flags
Flags which can be activated on the command-line are the
following:
-t or --time
Activate time estimation tools. This actually trig-
gers a clock when the process is running and pro-
duces duration estimations in CPU and user time at
the end.
Options
-cor--calib calib.ascii
This option can only be used together with the -g
option. It will generate a default ini file where
the names of the calibration files are deduced from
the contents of the provided `calib.ascii' file.
This file should contain two columns: the first one
gives the name of the calibration file, the second
one specifies its type.
-d or --display
This mode of jitter will check out the consistency
and print out the contents of the current ini file,
then exit. It is recommended to try out a configu-
ration with this option before launching the reduc-
tion process.
-f filename
Changes the name of the ini file from jitter.ini to
filename. This option is compatible with all other
options.
-g or --generate
Generates a default ini file in the current direc-
tory, and a default empty frame list called
framelist.ascii. You can fill up the ASCII list of
input names by using the ls command:
ls -1 *.fits >> framelist.ascii
Of course, the list of frames need not be named
`framelist.ascii', this is the default name only.
Change it if you wish in the ini file.
-w or --gui
Launches a GUI to use jitter
-h or --help
Displays a short reminder of possible options and
flags.
-ior--in filename
This option can only be used together with the -g
option. It will generate a default ini file where
the name of the input framelist is not the default
but the one provided to this option.
--offset
Displays a short help about the input offset file
format together with an example.
-oor--out basename
This option can only be used together with the -g
option. It will generate a default ini file where
the output basename is not the default but the one
provided to this option.
-ror--rb RBname
This option can only be used together with the -g
option. It will generate a default ini file where
input, output and calibration names will be deduced
from the contents of the provided reduction block.
A DFS-compliant reduction block is expected in
input.
Files
The ini file which is generated by using the -g option is
self-documented, all parameters are described in the file
comments.
The ini file consists of [Sections] followed by
keyword = value lines.
Section names and keywords are case-insensitive. Values
associated to keuwords may be integer, floating point num-
bers, character strings, or flags. Types associated to
keywords are usually indicated in the comment section.
Character strings as keyword values are case-sensitive.
Flags are given as Yes/Y/yes or No/N/no.
Comments in the ini file are identified by lines starting
with a hash (#) sign, and generally everything after a
semicolon (;) and before the end of the line. The semi-
colon is not mandatory, the two 5A following lines are
strictly equivalent:
ExposureTime = 1000 ; integer value in seconds
ExposureTime = 1000
Character strings are better given between double quotes,
but these are not compulsory. Without quotes, jitter will
understand as a character string any character between the
first and last non-blank characters. The following decla-
rations are equivalent, although the first one should be
preferred to avoid confusions:
Keyword = "HIERARCH ESO INSTRUMENT NAME" ;
Keyword = HIERARCH ESO INSTRUMENT NAME ;
Bugs
Some sections are yet unused in the ini file, they are
documented as such by their surrounding comments.
Author
Nicolas Devillard, European Southern Observatory.
e-mail : nDevil@eso.org
Part of eclipse Library