LatticeFit.h

Go to the documentation of this file.

//# LatticeFit.h: Fit every line of pixels parallel to any axis in a Lattice.
//# Copyright (C) 1994,1995,1999,2000,2002
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: casa-feedback@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
//#                        Charlottesville, VA 22903-2475 USA
 
#ifndef LATTICES_LATTICEFIT_H
#define LATTICES_LATTICEFIT_H
 
#include <casacore/casa/aips.h>
#include <casacore/lattices/Lattices/Lattice.h>
#include <casacore/lattices/Lattices/MaskedLattice.h>
#include <casacore/scimath/Fitting/LinearFit.h>
 
 
namespace casacore { //# NAMESPACE CASACORE - BEGIN
 
// <summary> 
// Fit every line of pixels parallel to any axis in a Lattice.
// </summary>
 
// <reviewed reviewer="" date="" tests="" demos="">
 
// <prerequisite>
//   <li> <linkto class=LinearFit>LinearFit</linkto>
//   <li> <linkto class=Lattice>Lattice</linkto>
// </prerequisite>
//
// <synopsis> 
 
// For every line in the lattice parallel to axis number <src>whichAxis</src>
// (often axis number 2, typically the frequency axis in a spectral line cube)
// independently fit the functions in fitter at the positions where
// <src>fitMask</src> is true. 
// </synopsis> 
//
// <example>
// Suppose one wanted to subtract a linear polynomial from every spectrum (3d
// axis) in an image. One could do this as follows:
// <srcBlock>
//    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;
//    fitter.setFunction(linear);
//    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);
// </srcBlock>
// </example>
//
// <motivation>
// Baseline fitting/continuum subtraction are important functions. This
// function essentially implements the IMLIN algorithm.
// </motivation>
//
// <todo asof="1995/09/01">
//   <li> Save the model parameters in an (optional) other lattice.
//   <li> Use logging classes, rather than the raw GlishSysEventSource.
//   <li> Allow per-pixel weights.
//   <li> Allow non-linear as well as linear LSQ fits.
// </todo>
 
// <linkfrom anchor="Baseline fitting" modules="Fitting"
// Related <here>fitting functions</here.
// </linkfrom>
 
class LatticeFit {
 
public:
 
// Fit baseline to lattice.   Presently the fit parameters, other than the last
// one(s) in fitter, are lost.  If <src>returnResiduals</src> is True, 
// return data-fit, otherwise return the fit.  For baseline and continuum 
// subtraction, returnResiduals would normally be True.
   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 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).
   static uInt fitProfiles (MaskedLattice<Float>* pOutFit,
                           MaskedLattice<Float>* pOutResid,
                           MaskedLattice<Float>& in,
                           Lattice<Float>* pSigma,
                           LinearFit<Float>& fitter, 
                           uInt axis, Bool showProgress=False);
};
 
 
} //# NAMESPACE CASACORE - END
 
#endif