Description
Makes a image using the Pixon algorithm. According to its developers,
the pixon method is:
a new way of viewing the problem of modeling the underlying, unblurred,
noise-free image. The goal of the [new] Pixon method model was to
construct the simplest, i.e. smoothest, model for the image that would
be consistent with the data, i.e. have an acceptable chi-square
fit. Being the simplest model, the derived image would be artifact
free, i.e. there would be no spurious sources, since by construction
the simplest model eliminates unneeded structures. In addition, the
model would necessarily be a "critical" model, i.e. most tightly
constrained by the data, and consequently have the most accurately
determined parameters.
In the simplest terms, the pixon method smooths a model locally as
much as is allowed by the specified noise level. This, like all
high performance estimation methods, the pixon approach works
best when the noise level is known and well-characterized.
The Pixon algorithm is available via an IDL library courtesy of the
Pixon LLC. This means that you must
have the library and IDL installed on your computer. The Pixon library
is available free of charge for your personal scientific use direct
from Pixon LLC. IDL is available
commercially from RSI.
Before pixon can be run, you must run setdata and setimage.
The algorithms available are:
- singledish
- The single dish observations are fed directly to the
pixon algorithm. Make the image cellsize considerably finer than Nyquist
sampling. The errors are those attached to each data
point. It is particularly important that the estimated sigmas
attached to the data are accurate.
- synthesis
- A dirty image and dirty point spread function are fed
to the pixon algorithm. The error is assumed to be constant across
the image. This approach is not formally correct and gives results
that are not optimum. Development of pixon processing for synthesis
observations is proceeding.
- test
- The standard Pixon LLC test is run.
Arguments
| algorithm |
in |
Algorithm to use |
|
|
Allowed: |
String:'singledish'|'synthesis'|'test' |
|
|
Default: |
'singledish' |
| sigma |
in |
Image sigma to try to achieve |
|
|
Allowed: |
Quantity |
|
|
Default: |
'0.001Jy' |
| model |
in |
Name of model image |
|
|
Allowed: |
String |
| async |
in |
Run asynchronously in the background? |
|
|
Allowed: |
Bool |
|
|
Default: |
!dowait |
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