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Static Public Member Functions | List of all members
casacore::LatticeFit Class Reference

Fit every line of pixels parallel to any axis in a Lattice. More...

#include <LatticeFit.h>

Static Public Member Functions

static uInt fitProfiles (Lattice< Float > &outImage, Vector< Float > &fittedParameters, LinearFit< Float > &fitter, const Lattice< Float > &inImage, uInt whichAxis, const Vector< Bool > &fitMask, Bool returnResiduals)
 Fit baseline to lattice. More...
static uInt fitProfiles (MaskedLattice< Float > *pOutFit, MaskedLattice< Float > *pOutResid, MaskedLattice< Float > &in, Lattice< Float > *pSigma, LinearFit< Float > &fitter, uInt axis, Bool showProgress=False)
 Fit baseline to MaskedLattice. More...

Detailed Description

Fit every line of pixels parallel to any axis in a Lattice.



For every line in the lattice parallel to axis number whichAxis (often axis number 2, typically the frequency axis in a spectral line cube) independently fit the functions in fitter at the positions where fitMask is true.


Suppose one wanted to subtract a linear polynomial from every spectrum (3d axis) in an image. One could do this as follows:

Image<Float> myImage("myimage"); // Get the image
uInt nchan = myImage.shape()(2); // 0 relative axis number
// Set up the fitter
Polynomial<AutoDiff<Float> > linear(1);
LinearFitSVD<Float> fitter;
Vector<Float> fittedParameters,
// Set up a mask indicating what channels we want to fit over. We want
// to fit over all channels.
Vector<Bool> fitMask(nchan); fitMask = True;
// Do the fit. True means subtract the fit from the model. In this case,
// We overwrite the input with the output.
fitProfiles (myImage, fittedParameters,fitter, myImage, 2, fitMask, True);


Baseline fitting/continuum subtraction are important functions. This function essentially implements the IMLIN algorithm.

To Do

Definition at line 96 of file LatticeFit.h.

Member Function Documentation

static uInt casacore::LatticeFit::fitProfiles ( Lattice< Float > &  outImage,
Vector< Float > &  fittedParameters,
LinearFit< Float > &  fitter,
const Lattice< Float > &  inImage,
uInt  whichAxis,
const Vector< Bool > &  fitMask,
Bool  returnResiduals 

Fit baseline to lattice.

Presently the fit parameters, other than the last one(s) in fitter, are lost. If returnResiduals is True, return data-fit, otherwise return the fit. For baseline and continuum subtraction, returnResiduals would normally be True.

static uInt casacore::LatticeFit::fitProfiles ( MaskedLattice< Float > *  pOutFit,
MaskedLattice< Float > *  pOutResid,
MaskedLattice< Float > &  in,
Lattice< Float > *  pSigma,
LinearFit< Float > &  fitter,
uInt  axis,
Bool  showProgress = False 

Fit baseline to MaskedLattice.

Fit and residuals can be optionally written (leave pointers at zero to not write out these lattices) You can optionally specify a weights lattice (1.0 if not given).

The documentation for this class was generated from the following file: