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#ifndef IMAGE_COORDINATES_H
#define IMAGE_COORDINATES_H
#include <algorithm>
#include <cmath>
#include <vector>
/**
* This class collects all the LM coordinate transform as defined in
* Perley (1999)'s "imaging with non-coplaner arrays".
*/
class ImageCoordinates
{
public:
template<typename T>
static void RaDecToLM(T ra, T dec, T phaseCentreRa, T phaseCentreDec, T &destL, T &destM)
{
const T
deltaAlpha = ra - phaseCentreRa,
sinDeltaAlpha = sin(deltaAlpha),
cosDeltaAlpha = cos(deltaAlpha),
sinDec = sin(dec),
cosDec = cos(dec),
sinDec0 = sin(phaseCentreDec),
cosDec0 = cos(phaseCentreDec);
destL = cosDec * sinDeltaAlpha;
destM = sinDec*cosDec0 - cosDec*sinDec0*cosDeltaAlpha;
}
template<typename T>
static T RaDecToN(T ra, T dec, T phaseCentreRa, T phaseCentreDec)
{
const T
cosDeltaAlpha = cos(ra - phaseCentreRa),
sinDec = sin(dec),
cosDec = cos(dec),
sinDec0 = sin(phaseCentreDec),
cosDec0 = cos(phaseCentreDec);
return sinDec*sinDec0 + cosDec*cosDec0*cosDeltaAlpha;
}
template<typename T>
static void LMToRaDec(T l, T m, T phaseCentreRa, T phaseCentreDec, T &destRa, T &destDec)
{
const T
cosDec0 = cos(phaseCentreDec),
sinDec0 = sin(phaseCentreDec),
lmTerm = sqrt((T) 1.0 - l*l - m*m),
deltaAlpha = atan2(l, lmTerm*cosDec0 - m*sinDec0);
destRa = deltaAlpha + phaseCentreRa;
destDec = asin(m*cosDec0 + lmTerm*sinDec0);
}
template<typename T>
static void XYToLM(size_t x, size_t y, T pixelSizeX, T pixelSizeY, size_t width, size_t height, T &l, T &m)
{
T midX = (T) width / 2.0, midY = (T) height / 2.0;
l = (midX - (T) x) * pixelSizeX;
m = ((T) y - midY) * pixelSizeY;
}
template<typename T>
static void LMToXY(T l, T m, T pixelSizeX, T pixelSizeY, size_t width, size_t height, int &x, int &y)
{
T midX = (T) width / 2.0, midY = (T) height / 2.0;
x = round(-l / pixelSizeX) + midX;
y = round(m / pixelSizeY) + midY;
}
template<typename T>
static void LMToXYfloat(T l, T m, T pixelSizeX, T pixelSizeY, size_t width, size_t height, T &x, T &y)
{
T midX = (T) width / 2.0, midY = (T) height / 2.0;
x = -l / pixelSizeX + midX;
y = m / pixelSizeY + midY;
}
template<typename T>
static T AngularDistance(T ra1, T dec1, T ra2, T dec2)
{
T sinDec1, sinDec2, cosDec1, cosDec2;
SinCos(dec1, &sinDec1, &cosDec1);
SinCos(dec2, &sinDec2, &cosDec2);
T cosVal = sinDec1*sinDec2 + cosDec1*cosDec2*std::cos(ra1 - ra2);
// Rounding errors sometimes cause cosVal to be slightly larger than 1, which would cause
// an NaN return value.
return cosVal <= 1.0 ? std::acos(cosVal) : 0.0;
}
template<typename T>
static T MeanRA(const std::vector<T>& raValues)
{
std::vector<T> sorted(raValues);
for(size_t i=0; i!=sorted.size(); ++i) {
while(sorted[i] >= 2*M_PI) sorted[i] -= 2.0*M_PI;
while(sorted[i] < 0.0) sorted[i] += 2.0*M_PI;
}
std::sort(sorted.begin(), sorted.end());
T gapSize = 0.0, gapCentre = 0.0;
for(size_t i=0; i!=sorted.size(); ++i)
{
double dist;
if(i == sorted.size()-1)
dist = 2.0*M_PI + sorted.front() - sorted.back();
else
dist = sorted[i+1] - sorted[i];
if(dist > gapSize)
{
gapSize = dist;
gapCentre = sorted[i] + gapSize*0.5;
}
}
if(gapCentre >= 2.0*M_PI) gapCentre-=2.0*M_PI;
T sum = 0.0;
for(size_t i=0; i!=sorted.size(); ++i)
{
if(sorted[i] < gapCentre)
sum += sorted[i];
else
sum += sorted[i] - 2.0*M_PI;
}
sum /= sorted.size();
if(sum < 0.0)
return sum + 2.0*M_PI;
else
return sum;
}
private:
static void SinCos(double angle, double* sinAngle, double* cosAngle)
{ sincos(angle, sinAngle, cosAngle); }
static void SinCos(long double angle, long double* sinAngle, long double* cosAngle)
{ sincosl(angle, sinAngle, cosAngle); }
static void SinCos(float angle, float* sinAngle, float* cosAngle)
{ sincosf(angle, sinAngle, cosAngle); }
ImageCoordinates();
};
#endif
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