Image Analysis with CASA - ESO

More documents

Recommendations

Info

Imageplane Component Fitting imfit 2D Gaussian Fitting (one or more Gaussian component) to sources in an image see also uvmodelfit for fit in the visibility domain CASA : inp imfit # imfit :: Fit one or more elliptical Gaussian components on an image region(s) imagename = '' # Name of the input image box = '' # Specify one or more box regions for the fit region = '' # Region name or region specified using rg tool chans = '' # Spectral channels on which to perform fit stokes = '' # Stokes parameter to fit. If blank, first stokes plane is used mask = '' # Mask to be applied to the image includepix = [] # Range of pixel values to include for fitting @ excludepix = [] # Range of pixel values to exclude for fitting @ residual = '' # Name of output residual image @ model = '' # Name of output model image @ estimates = '' # Name of file containing initial estimates of component parameters @ logfile = '' # Name of file to write fit results newestimates = '' # File to write fit results which can be used as initial estimates for next run complist = '' # Name of output component list table chan = 1 # DEPRECATED. USE chans INSTEAD async = False # If true the taskname must be started using imfit(...) 18
If only 1 Gaussian component (default), the fit will do without prior guess. If more, estimates have to be input from a file containing (for each component): peak intensity, peak xpix value, peak ypix value, major axis, minor axis, position angle, fixed fixed = combination of: f x y a b p, for the parameters to be kept constant Example: Simultaneous fit of 2 Gaussian components, the first one fixed in xy position prior_guess=open(’inputparameter.estimate’,’w’) print >> prior_guess,’# peak, x, y, bmaj, bmin, pa’ print >> prior_guess,’0.02, 128, 128, 0.4arcsec, 0.2arcsec, 120deg, xy' print >> prior_guess,’0.01, 113, 120, 0.4arcsec, 0.2arcsec, 120deg' prior_guess.close() xfit = imfit( imagename=’my.image’, estimates=’inputparameter.estimate’, logfile='fitresults.log’, box=’118,118,138,138,103,110,110,130') Results are returned as a Python dictionary (xfit) + can be written in a logfile or a component list table If the image has a clean beam, the report will contain both the convolved and the deconvolved fit results. 19
Page 1 and 2: Image Analysis with CASA Sebastien
Page 3 and 4: View images Extract information fro
Page 5 and 6: Working with images: General tasks
Page 7 and 8: Viewer CASA> viewer and then use th
Page 9 and 10: Header hdkey for reference beammaj
Page 11 and 12: Defining box / region - Command lin
Page 13 and 14: Image Statistics imstat : calculate
Page 15 and 16: Mathematical operations on images i
Page 17: Smooth images imsmooth - Image conv
Page 21 and 22: Working with spectral data cube
Page 23 and 24: Extract a spectrum - Script mode Us
Page 25 and 26: Moments Images Sometimes, informati
Page 27 and 28: Spectral Lines Search 1) Use SPLATA
Page 29 and 30: ToolKit For (very?) advanced users,

Image Analysis with CASA - ESO

Create successful ePaper yourself

Delete template?

Save as template?