VectorKernel.h

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// # VectorKernel.h: generate Vector kernels
// # Copyright (C) 1996,1997,1998,1999,2000,2001
// # 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 SCIMATH_VECTORKERNEL_H
#define SCIMATH_VECTORKERNEL_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Arrays/Vector.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class Regex;
class String;
 
// <summary>
// Make a Vector smoothing kernel from a kernel specification
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="" date="yyyy/mm/dd" tests="" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class="Vector">Vector</linkto>
// </prerequisite>
 
// <etymology>
// Returns a vector from a smoothing kernel specification.
// </etymology>
 
// <synopsis>
// This class takes a smoothing kernel type and a width, and
// generates  a Vector holding that kernel.  It can be used
// in conjunction with the separable image convolver,
// SepImageConvolver
//
// The kernels can be normalized so that the peak of the
// kernel is 1, or 1/area under the kernel. The latter ensures
// conservation of integrated pixel value (the usual jargon
// is conservation of flux for images) and is the default.
// </synopsis>
 
// <example>
// <srcBlock>
// </srcBlock>
// </example>
 
// <motivation>
// </motivation>
 
// <todo asof="1990/03/31">
//   <li>
// </todo>
 
class VectorKernel {
 public:
  enum KernelTypes {
 
    // Box-car smoothing kernel
    BOXCAR,
 
    // Gaussian smoothing kernel
    GAUSSIAN,
 
    // Hanning smoothing kernel
    HANNING,
 
    NKERNELS
  };
 
  // Create kernel vector for width in pixels.  For Gaussian, width is FWHM,
  // for Boxcar, width is full width.  For Hanning width is ignored.
  // If useShapeExactly is True, the provided shape is used exactly.
  // If useShapeExactly is False,
  // the kernel length will be the max of the provided shape and an
  // autoestimate (e.g. from +/- 5sigma limits for a Gaussian).
  // <group>
  static Vector<Double> make(KernelTypes kernelType, Double width, uInt shape, Bool useShapeExactly,
                             Bool peakIsUnity = False);
  static Vector<Float> make(KernelTypes kernelType, Float width, uInt shape, Bool useShapeExactly,
                            Bool peakIsUnity = False);
  // </group>
 
  // Helper function to convert a string containing a list of desired smoothed kernel types
  // to the correct <src>Vector<Int></src> required for the <src>setSmooth</src> function.
  // This may be usful if your user interface involves strings rather than integers.
  // A new value is added to the output vector (which is resized appropriately) if any of the
  // substrings "boxcar", "gaussian" or "hanning" (actually "box", "gauss", and "hann"
  // will do) is present.
  static Vector<Int> toKernelTypes(const String& kernels, const std::regex& delimiter);
  static Vector<Int> toKernelTypes(const Vector<String>& kernels);
  static VectorKernel::KernelTypes toKernelType(const String& kernel);
  static String fromKernelType(KernelTypes kernelType);
};
 
}  // namespace casacore
 
#endif