clean – Invert and deconvolve images with selected algorithm – imaging task
Description
Form images from visibilities. Handles continuum and spectral line cubes.
Parameters
Parameter |
Default |
Description |
|---|---|---|
vis |
|
|
imagename |
|
|
outlierfile |
|
|
field |
|
|
spw |
|
|
selectdata |
|
|
timerange |
|
|
uvrange |
|
|
antenna |
|
|
scan |
|
|
observation |
|
|
intent |
|
|
mode |
|
|
resmooth |
|
|
gridmode |
|
|
wprojplanes |
|
|
facets |
|
|
cfcache |
|
|
rotpainc |
|
|
painc |
|
|
aterm |
|
|
psterm |
|
|
mterm |
|
|
wbawp |
|
|
conjbeams |
|
|
epjtable |
|
|
interpolation |
|
|
niter |
|
|
gain |
|
|
threshold |
|
|
psfmode |
|
|
imagermode |
|
|
ftmachine |
|
|
mosweight |
|
|
scaletype |
|
|
multiscale |
|
|
negcomponent |
|
|
smallscalebias |
|
|
interactive |
|
|
mask |
|
|
nchan |
|
|
start |
|
|
width |
|
|
outframe |
|
|
veltype |
|
|
imsize |
|
|
cell |
|
|
phasecenter |
|
|
restfreq |
|
|
stokes |
|
|
weighting |
|
|
robust |
|
|
uvtaper |
|
|
outertaper |
|
|
innertaper |
|
|
modelimage |
|
|
restoringbeam |
|
|
pbcor |
|
|
minpb |
|
|
usescratch |
|
|
noise |
|
|
npixels |
|
|
npercycle |
|
|
cyclefactor |
|
|
cyclespeedup |
|
|
nterms |
|
|
reffreq |
|
|
chaniter |
|
|
flatnoise |
|
|
allowchunk |
|
Parameter Explanations
vis
''
Name of input visibility file
imagename
''
Pre-name of output images
outlierfile
''
Text file with image names, sizes, centers for outliers
field
''
Field Name or id
spw
''
Spectral windows e.g. '0~3', '' is all
selectdata
True
Other data selection parameters
timerange
''
Range of time to select from data
uvrange
''
Select data within uvrange
antenna
''
Select data based on antenna/baseline
scan
''
Scan number range
observation
''
Observation ID range
intent
''
Scan Intent(s)
mode
'mfs'
Spectral gridding type (mfs, channel, velocity, frequency)
resmooth
False
Re-restore the cube image to a common beam when True
gridmode
''
Gridding kernel for FFT-based transforms, default='' None
wprojplanes
int(-1)
Number of w-projection planes for convolution; -1 => automatic determination
facets
int(1)
Number of facets along each axis (main image only)
cfcache
'cfcache.dir'
Convolution function cache directory
rotpainc
float(5.0)
Parallactic angle increment (degrees) for OTF A-term rotation
painc
float(360.0)
Parallactic angle increment (degrees) for computing A-term
aterm
True
Switch-on the A-Term?
psterm
False
Switch-on the PS-Term?
mterm
True
Switch-on the M-Term?
wbawp
False
Trigger the wide-band A-Projection algorithm?
conjbeams
True
Use frequency conjugate beams in WB A-Projection algorithm?
epjtable
''
Table of EP-Jones parameters
interpolation
'linear'
Spectral interpolation (nearest, linear, cubic).
niter
int(500)
Maximum number of iterations
gain
float(0.1)
Loop gain for cleaning
threshold
{'value': float(0.0), 'unit': 'mJy'}
Flux level to stop cleaning, must include units: '1.0mJy'
psfmode
'clark'
Method of PSF calculation to use during minor cycles
imagermode
'csclean'
Options: 'csclean' or 'mosaic', '', uses psfmode
ftmachine
'mosaic'
Gridding method for the image
mosweight
False
Individually weight the fields of the mosaic
scaletype
'SAULT'
Controls scaling of pixels in the image plane. default='SAULT'; example: scaletype='PBCOR' Options: 'PBCOR','SAULT'
multiscale
numpy.array( [ int(0) ] )
Deconvolution scales (pixels); [] = standard clean
negcomponent
int(-1)
Stop cleaning if the largest scale finds this number of neg components
smallscalebias
float(0.6)
a bias to give more weight toward smaller scales
interactive
False
Use interactive clean (with GUI viewer)
mask
numpy.array( [ ] )
Cleanbox(es), mask image(s), region(s), or a level
nchan
int(-1)
Number of channels (planes) in output image; -1 = all
start
int(0)
start of output spectral dimension
width
int(1)
width of output spectral channels
outframe
''
default spectral frame of output image
veltype
'radio'
velocity definition (radio, optical, true)
imsize
numpy.array( [ int(256),int(256) ] )
x and y image size in pixels. Single value: same for both
cell
{'value': float(1.0), 'unit': 'arcsec'}
x and y cell size(s). Default unit arcsec.
phasecenter
''
Image center: direction or field index
restfreq
''
Rest frequency to assign to image (see help)
stokes
'I'
Stokes params to image (eg I,IV,IQ,IQUV)
weighting
'natural'
Weighting of uv (natural, uniform, briggs, …)
robust
float(0.0)
Briggs robustness parameter
uvtaper
False
Apply additional uv tapering of visibilities
outertaper
numpy.array( [ '' ] )
uv-taper on outer baselines in uv-plane
innertaper
numpy.array( [ ] )
uv-taper in center of uv-plane (not implemented)
modelimage
''
Name of model image(s) to initialize cleaning
restoringbeam
numpy.array( [ ] )
Output Gaussian restoring beam for CLEAN image
pbcor
False
Output primary beam-corrected image
minpb
float(0.2)
Minimum PB level to use
usescratch
False
True if to save model visibilities in MODEL_DATA column
noise
'1.0Jy'
noise parameter for briggs abs mode weighting
npixels
int(0)
number of pixels for superuniform or briggs weighting
npercycle
int(100)
Clean iterations before interactive prompt (can be changed)
cyclefactor
float(1.5)
Controls how often major cycles are done. (e.g. 5 for frequently)
cyclespeedup
int(-1)
Cycle threshold doubles in this number of iterations
nterms
int(1)
Number of Taylor coefficients to model the sky frequency dependence
reffreq
''
Reference frequency (nterms > 1),'' uses central data-frequency
chaniter
False
Clean each channel to completion (True), or all channels each cycle (False)
flatnoise
True
Controls whether searching for clean components is done in a constant noise residual image (True) or in an optimal signal-to-noise residual image (False)
allowchunk
False
Divide large image cubes into channel chunks for deconvolution