.help newextraction Jul84 noao.twodspec.multispec
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NAME
newextraction -- Initialize a new MULTISPEC extraction
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USAGE
newextraction image template
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PARAMETERS
.ls image
Image to be extracted.
.le
.ls template
The previously created database for the template image is used to initialize
the new database.  If the null string is given then the database is not
initialized.
.le
.ls sample_lines = "10x50"
Sample image lines in which the spectra positions are to be determined and,
optionally, modeled.  This parameter is not used if a template image is given.
.le
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DESCRIPTION
To extract the spectra from a multi-spectra image a database must be created
and associated with the image.  This task creates the database with a name
formed by adding the extension '.db' and initializes some of the database
entries.

The sample lines are used to track the spectra positions and, if an analytic
profile model is to be fit to the spectra, to map profile shape changes.
The image lines only need be sampled enough to track \fInon-linear\fR position
distortions and significant profile shape changes since interpolation
is used between the sample lines.  Though specifying just one sample
line is allowed using at least two sample lines is recommended to allow for
any slope in the position of the spectra.  Specifying all the image lines
will greatly increase the processing time and is never justified.

Using a previous database to initialize the new database is useful if the
new image is only slightly different in the positions and profiles of the
spectra.  In some cases extraction may proceed immediately without any
further position determination and modeling.  Further modeling
and spectra position determinations will refine the previously determined
parameters with an increase in execution time.  Using a template image is
particularly important if the first image extracted has strong spectra
and subsequent images have much weaker spectra since the automatic spectra
position location and profile modeling may yield poor results for very weak
spectra.
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EXAMPLES
To initialize a MULTISPEC database for extracting the spectra in
the image \fIimage1\fR:

	cl> newextraction image1 ""

To create a new MULTISPEC database for extracting the spectra in
the image \fIimage2\fR  using \fIimage1\fR as a template image:

.nf
	cl> newextraction image2 image1
.fi
.endhelp
