Keywords: imager

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### Typical deconvolution session

           1 read beam demo
           2 read dirty demo
           3 clean ?
           4 hogbom /flux 0 1
           5 show residual
           6 show clean
           7 write clean demo
           8 let name demo
           9 show noise
          10 let ares 0.5*noise
          11 clean ?
          12 hogbom /flux 0 1
          13 let niter 2000
          14 clean ?
          15 hogbom /flux 0 1
          16 show residual
          17 show clean
          18 for iplane 1 to 10
          19    show clean iplane
          20    support
          21    hogbom iplane /flux 0 1
          22    write support "demo-"'iplane'
          23 next iplane
          24 show residual
          25 view cct
          26 view clean
          27 write residual demo
          28 write clean demo
          29 write cct demo

Comments:

Steps 1-2
  Read dirty beam and dirty image from the cyan`demo.beam` and cyan`demo.lmv` files. Those steps are not needed if the dirty beam and image are already stored in the internal buffer, i.e. if you have imaged the uv table just before in the same [rgb]1,0,0IMAGER session.
Steps 3-6
  Print the current state of the control parameters, deconvolve the dirty image using the magenta`HOGBOM` algorithm (step 3) and look at the results (residual and clean images). The magenta`/flux 0 1` option pop-up the visualization of the cumulative flux deconvolved as the clean components are found.
Steps 8-12
  Estimate the empirical noise through the magenta`SHOW NOISE` command after this first deconvolution and set the `ares` stopping criterion accordingly. Check that the new value of `ares` has been correctly set (step 11) and restart deconvolution.
Steps 13-17
  Increase the number of clean components as the previous deconvolution stopped before the residual image reached the `ares` value. Restart deconvolution and look at results.
Steps 18-23
  Attempt to improve deconvolution by definition of a support per plane and deconvolve this plane accordingly. The support is stored in a file for further re-use. The deconvolution results are then displayed.
Steps 24-26
  Display the residual images, visualize the cumulative flux as a function of the clean component number and visualize the clean spectra cube in an interactive way.
Steps 27-29
  Write residual image, clean image and clean component list in cyan`demo.lmv-res`, cyan`demo.lmv-clean` and cyan`demo.cct` files for later use.

Typical deconvolution session using other `CLEAN` algorithm would look very similar. The main difference would be the possible tuning of other control parameters. A deconvolution session using magenta`MX` would start differently as the imaging and deconvolution are done in the same step:

           1 read uv demo
           2 mx ?
           3 mx /flux 0 1
           4 show residual
           5 show clean
           6 write * demo
    %       6 write beam demo
    %       7 write dirty demo
    %       8 write clean demo
    %       9 write residual demo
    %      10 write cct demo

Comments:

Step 1
  Read the `demo.uvt` uv table in an internal buffer.
Step 2
  Check current state of the variables that control the imaging and deconvolution.
Steps 3-5
  Deconvolve and look at the results.
Steps 6-10
  Write all the internal buffers on disk files.

All the tuning of the typical imaging and deconvolution sessions could be used in this magenta`MX` session although they are not repeated here.

Next: Practical advices Up: The family of CLEAN Previous: Restoring step: magentaUV_RESTORE Contents Index