deconvolve¶
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deconvolve
(imagename, model='', psf=[''], alg='clark', niter=10, gain=0.1, threshold=0.0, mask='', scales=[0, 3, 10], sigma=0.0, targetflux=1.0, prior='')[source]¶ Image based deconvolver
[Description] [Examples] [Development] [Details]
- Parameters
- Description
deconvolve performs minor cycle deconvolution directly on a dirty image. No MS is required.
Warning
ALERT: deconvolve is defunct. The task deconvolve is currently being refactored and will be available again in an upcoming release. For the moment use tclean (although tclean requires an MS at this stage), or please use deconvolve in an older version of CASA (v4.7.2 or earlier).
Parameter descriptions
imagename
The input dirty image that will be deconvolved.
model
The output cleaned image containing a deconvolved point model.
psf
Can be either be an image (e.g., a psf that tclean has calculated), or a list of values that define a Gaussian, e.g., psf=[‘3arcsec’, ‘2.5arcsec’, ‘10deg’] defines a Gaussian with ‘3arcsec’ as the major axis, ‘2.5arcsec’ as the minor axis, and a position angle of 10 degrees.
alg
The clean algorithm to use by deconvolve. Several algorithms are available to deconvolve an image with a known psf (dirty beam), or a Gaussian beam. The algorithms are ‘clark’ (default) and ‘hogbom’ clean, ‘multiscale’ clean and a Maximum Entropy ‘mem’ clean. Details on the algorithms are given in the Synthesis Imaging chapter in the page describing Deconvolution Algorithms.
alg=’multiscale’ expandable parameters
scales
A list of scales in units of pixels (see the deconvolve examples tab).
alg=’mem’ expandable parameters
sigma
This parameter allows the user to input an expected noise value, which will allow for a faster convergence.
targetflux
The estimated total flux in the image.
prior
A starting model to be used by deconvolve. If no prior is provided, a flat image will be used.
niter
The number of iterations to perform on the image. Default: 10
gain
Sets the CLEAN gain parameter. Default: 0.1
threshold
Sets the lower level below which sources will not be deconvolved.
mask
The image mask to limit the region of deconvolution.
- Examples
Deconvolve the dirty image ‘mydirtyimage.image’ with a dirty beam (psf) ‘mydirtyimage.psf’. No MS is required as only minor cycles are performed. We are using the ‘multiscale’ clean algorithm with scales of 0, 3, and 10 pixels. The stopping criteria are either 10000 iterations, or an RMS threshold of 10mJy:
deconvolve(imagename='mydirtyimage.image', model='mycleanimage.image', psf='mydirtyimage.psf', alg='multiscale', scales=[0,3,10], niter=10000, gain=0.1, threshold='10mJy')
- Development
No additional development details
- Parameter Details
Detailed descriptions of each function parameter
imagename (string)
- Input image to deconvolvemodel (string='')
- Output image containing deconvolved point modelpsf (stringArray=[''])
- Point spread function (dirty beam)alg (string='clark')
- Algorithm to use (clark, hogbom, multiscale, mem)niter (int=10)
- number of iteration in deconvolution processgain (double=0.1)
- CLEAN gain parameterthreshold (double=0.0)
- level below which sources will not be deconvolvedmask (string='')
- image mask to limit region of deconvolutionscales (intArray=[0, 3, 10])
- scale sizes (pixels) to deconvolvesigma (double=0.0)
- mem parameter: Expected noise in imagetargetflux (double=1.0)
- mem parameter: Estimated total flux in imageprior (string='')
- mem parameter: prior image for mem search