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//# VectorKernel.cc: generate moments from an image
//# Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002
//# 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
//
#include <casacore/scimath/Mathematics/VectorKernel.h>
#include <casacore/casa/aips.h>
#include <casacore/casa/Arrays/Vector.h>
#include <casacore/casa/Arrays/ArrayUtil.h>
#include <casacore/casa/IO/ArrayIO.h>
#include <casacore/casa/Exceptions/Error.h>
#include <casacore/scimath/Functionals/Gaussian1D.h>
#include <casacore/casa/Logging/LogIO.h>
#include <casacore/casa/BasicSL/String.h>
#include <casacore/casa/BasicSL/Constants.h>
#include <casacore/casa/BasicMath/Math.h>
#include <casacore/casa/Utilities/Regex.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
Vector<Double> VectorKernel::make(KernelTypes kernelType, Double width,
uInt shape, Bool useShapeExactly, Bool peakIsUnity)
{
LogIO os(LogOrigin("VectorKernel", "make(Double)"));
if (shape <=1) {
os << "Shape must be > 1" << LogIO::EXCEPTION;
}
//
Vector<Double> kernel;
uInt nPixels = 0;
if (kernelType == GAUSSIAN) {
// Gaussian. The volume error is less than 6e-5% for +/- 5 sigma limits
// width is FWHM
const Double sigma = width / sqrt(Double(8.0) * M_LN2);
if (useShapeExactly) {
nPixels = shape;
} else {
nPixels = max(shape,(uInt(5*sigma + 0.5) + 1) * 2);
}
kernel.resize(nPixels);
//
const Double refPix = Double(nPixels)/2;
Double norm;
if (peakIsUnity) {
norm = 1.0;
} else {
norm = 1.0 / (sigma * sqrt(2.0 * M_PI));
}
const Gaussian1D<Double> gauss(norm, refPix, Double(width));
for (uInt j=0; j<nPixels; j++) kernel(j) = gauss(Double(j));
} else if (kernelType == BOXCAR) {
uInt iWidth = uInt(width+0.5);
if (useShapeExactly) {
nPixels = shape;
} else {
nPixels = max(shape,iWidth+1);
}
kernel.resize(nPixels);
// Try and center kernel
uInt startPix = max(0u,(nPixels - iWidth)/2);
uInt endPix = min(nPixels,startPix+iWidth-1);
//
Double norm;
if (peakIsUnity) {
norm = 1.0;
} else {
norm = Double(iWidth);
}
//
kernel = 0.0;
for (uInt i=startPix; i<=endPix; i++) {
kernel(i) = 1.0 / norm;
}
} else if (kernelType == HANNING) {
// kernel always shape 3
/*nPixels = 3;
kernel.resize(nPixels);
if (peakIsUnity) {
kernel(0) = 0.5;
kernel(1) = 1.0;
kernel(2) = 0.5;
} else {
kernel(0) = 0.25;
kernel(1) = 0.5;
kernel(2) = 0.25;
}*/
nPixels = shape;
kernel.resize( nPixels );
int nextIndex = shape + 1;
Double normalizer = 1.0 / ( nextIndex );
if ( peakIsUnity ){
normalizer = 0.5;
}
double piValue = 4 * atan( 1 );
int middle = (shape-1)/2;
int endIndex = nextIndex / 2;
for ( int i = 0; i < endIndex; i++ ){
Double xValue = endIndex - i;
Double angleValue = ( 2 * piValue * xValue) / nextIndex;
double value = 1-cos( angleValue);
value = value * normalizer;
kernel[middle - i] = value;
kernel[middle + i] = value;
}
}
//
return kernel;
}
Vector<Float> VectorKernel::make(KernelTypes kernelType, Float width,
uInt shape, Bool useShapeExactly, Bool peakIsUnity)
{
Double tw = width;
Vector<Double> tmp = make(kernelType, tw, shape, useShapeExactly, peakIsUnity);
Vector<Float> kernel(tmp.nelements());
for (uInt i=0; i<tmp.nelements(); i++) kernel(i) = Float(tmp(i));
return kernel;
}
Vector<Int> VectorKernel::toKernelTypes (const String& kernels,
const std::regex& delimiter)
{
const Vector<String> kernelStrings = stringToVector(kernels, delimiter);
return VectorKernel::toKernelTypes(kernelStrings);
}
Vector<Int> VectorKernel::toKernelTypes (const Vector<String>& kernels)
{
const uInt n = kernels.nelements();
Vector<Int> kernelTypes(n);
for (uInt i=0; i<n; i++) {
kernelTypes(i) = VectorKernel::toKernelType(kernels(i));
}
return kernelTypes;
}
VectorKernel::KernelTypes VectorKernel::toKernelType (const String& kernel)
{
String kernel2 = upcase(kernel);
String kernel3(kernel2.at(0,1));
if (kernel3==String("B")) {
return VectorKernel::BOXCAR;
} else if (kernel3==String("G")) {
return VectorKernel::GAUSSIAN;
} else if (kernel3==String("H")) {
return VectorKernel::HANNING;
} else {
ThrowIf (True, "Illegal kernel type " + kernel);
}
return VectorKernel::BOXCAR; //# to satisfy compiler
}
String VectorKernel::fromKernelType (KernelTypes kernelType)
{
String type;
if (kernelType==BOXCAR) {
type = String("BOXCAR");
} else if (kernelType==GAUSSIAN) {
type = String("GAUSSIAN");
} else if (kernelType==HANNING) {
type = String("HANNING");
}
return type;
}
} //# NAMESPACE CASACORE - END
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