lsst::meas::algorithms::photometry Namespace Reference

Classes
struct	fuzzyCompare
class	SincCoeffs

Functions
template<typename MaskedImageT >
std::pair< double, double >	calculateSincApertureFlux (MaskedImageT const &mimage, afw::geom::ellipses::Ellipse const &ellipse, double const innerFactor)

Function Documentation

template<typename MaskedImageT >

std::pair< double, double > lsst::meas::algorithms::photometry::calculateSincApertureFlux	(	MaskedImageT const &	mimage,
		afw::geom::ellipses::Ellipse const &	ellipse,
		double const	innerFactor
	)

Workhorse routine to calculate elliptical aperture fluxes

Calculate the flux in an elliptical annulus

The outer boundary is defined by an ellipse, while the inner boundary is a scaled version of the outer ellipse.

Parameters

mimage	Image to measure
ellipse	Outer aperture
innerFactor	Scale to apply to ellipse for inner boundary

Definition at line 687 of file SincFlux.cc.

{
    double flux = std::numeric_limits<double>::quiet_NaN();
    double fluxErr = std::numeric_limits<double>::quiet_NaN();
    
    typedef typename MaskedImageT::Image Image;
    typedef typename Image::Pixel Pixel;
    typedef typename Image::Ptr ImagePtr;
    
    // BBox for data image
    afwGeom::BoxI imageBBox(mimage.getBBox());


    // make the coeff image
    // compute c_i as double integral over aperture def g_i(), and sinc()
    CONST_PTR(Image) cimage0 = SincCoeffs<Pixel>::get(ellipse.getCore(), innerFactor);
        
    // as long as we're asked for the same radius, we don't have to recompute cimage0
    // shift to center the aperture on the object being measured
    ImagePtr cimage = afwMath::offsetImage(*cimage0, ellipse.getCenter().getX(), ellipse.getCenter().getY());
    afwGeom::BoxI bbox(cimage->getBBox());
#if 0
    // I (Steve Bickerton) think this should work, but doesn't.
    // For the time being, I'll do the bounds check here
    // ... should determine why bbox/image behaviour not as expected.
    afwGeom::BoxI mbbox(mimage.getBBox());
    bbox.clip(mbbox);
    afwGeom::Point2I cimXy0(cimage->getXY0());
    bbox.shift(-cimage->getX0(), -cimage->getY0());
    cimage = typename Image::Ptr(new Image(*cimage, bbox, false));
    cimage->setXY0(cimXy0);
#else
    int x1 = (cimage->getX0() < mimage.getX0()) ? mimage.getX0() : cimage->getX0();
    int y1 = (cimage->getY0() < mimage.getY0()) ? mimage.getY0() : cimage->getY0();
    int x2 = (cimage->getX0() + cimage->getWidth() > mimage.getX0() + mimage.getWidth()) ?
        mimage.getX0() + mimage.getWidth() - 1 : cimage->getX0() + cimage->getWidth() - 1;
    int y2 = (cimage->getY0() + cimage->getHeight() > mimage.getY0() + mimage.getHeight()) ?
        mimage.getY0() + mimage.getHeight() - 1 : cimage->getY0() + cimage->getHeight() - 1; 
    
    // if the dimensions changed, put the image in a smaller bbox
    if ( (x2 - x1 + 1 != cimage->getWidth()) || (y2 - y1 + 1 != cimage->getHeight()) ) {
        bbox = afwGeom::BoxI(afwGeom::Point2I(x1 - cimage->getX0(), y1 - cimage->getY0()),
                             afwGeom::Extent2I(x2 - x1 + 1, y2 - y1 + 1));
        cimage = ImagePtr(new Image(*cimage, bbox, afwImage::LOCAL, false));
        
        // shift back to correct place
        cimage = afwMath::offsetImage(*cimage, x1, y1);
                bbox = afwGeom::BoxI(afwGeom::Point2I(x1, y1), 
                                                          afwGeom::Extent2I(x2-x1+1, y2-y1+1));
    }
#endif
        
    // pass the image and cimage into the wfluxFunctor to do the sum
    FootprintWeightFlux<MaskedImageT, Image> wfluxFunctor(mimage, cimage);
    
    afwDet::Footprint foot(bbox, imageBBox);
    wfluxFunctor.apply(foot);
    flux = wfluxFunctor.getSum();
    fluxErr = ::sqrt(wfluxFunctor.getSumVar());

    return std::make_pair(flux, fluxErr);
}