ScaledApertureFlux.cc

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// -*- lsst-c++ -*-
/*
 * LSST Data Management System
 * Copyright 2008-2016 AURA/LSST.
 *
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the LSST License Statement and
 * the GNU General Public License along with this program.  If not,
 * see <http://www.lsstcorp.org/LegalNotices/>.
 */

#include "lsst/afw/table/Source.h"
#include "lsst/meas/base/ApertureFlux.h"
#include "lsst/meas/base/ScaledApertureFlux.h"
#include "lsst/meas/base/SincCoeffs.h"
#include "lsst/afw/detection/Psf.h"

namespace lsst {
namespace meas {
namespace base {

ScaledApertureFluxAlgorithm::ScaledApertureFluxAlgorithm(Control const& ctrl, std::string const& name,
                                                         afw::table::Schema& schema)
        : _ctrl(ctrl),
          _instFluxResultKey(
                  FluxResultKey::addFields(schema, name, "instFlux derived from PSF-scaled aperture")),
          _centroidExtractor(schema, name) {
    _flagHandler = FlagHandler::addFields(schema, name, ApertureFluxAlgorithm::getFlagDefinitions());
}

void ScaledApertureFluxAlgorithm::measure(afw::table::SourceRecord& measRecord,
                                          afw::image::Exposure<float> const& exposure) const {
    geom::Point2D const center = _centroidExtractor(measRecord, _flagHandler);
    double const radius = exposure.getPsf()->computeShape(center).getDeterminantRadius();
    double const fwhm = 2.0 * std::sqrt(2.0 * std::log(2)) * radius;
    double const size = _ctrl.scale * fwhm;
    afw::geom::ellipses::Axes const axes(size, size);

    // ApertureFluxAlgorithm::computeSincFlux requires an ApertureFluxControl as an
    // argument. All that it uses it for is to read the type of warping kernel.
    ApertureFluxControl apCtrl;
    apCtrl.shiftKernel = _ctrl.shiftKernel;

    Result result = ApertureFluxAlgorithm::computeSincFlux(
            exposure.getMaskedImage(), afw::geom::ellipses::Ellipse(axes, center), apCtrl);
    measRecord.set(_instFluxResultKey, result);

    for (std::size_t i = 0; i < ApertureFluxAlgorithm::getFlagDefinitions().size(); i++) {
        FlagDefinition const& iter = ApertureFluxAlgorithm::getFlagDefinitions()[i];
        if (result.getFlag(iter.number)) {
            _flagHandler.setValue(measRecord, iter.number, true);
        }
    }
}

void ScaledApertureFluxAlgorithm::fail(afw::table::SourceRecord& measRecord, MeasurementError* error) const {
    _flagHandler.handleFailure(measRecord, error);
}

ScaledApertureFluxTransform::ScaledApertureFluxTransform(Control const& ctrl, std::string const& name,
                                                         afw::table::SchemaMapper& mapper)
        : FluxTransform{name, mapper} {
    for (std::size_t i = 0; i < ApertureFluxAlgorithm::getFlagDefinitions().size(); i++) {
        std::string flagName = ApertureFluxAlgorithm::getFlagDefinitions()[i].name;
        afw::table::Key<afw::table::Flag> key =
                mapper.getInputSchema().find<afw::table::Flag>(name + "_" + flagName).key;
        if (key.isValid()) {
            mapper.addMapping(key);
        }
    }
}

}  // namespace base
}  // namespace meas
}  // namespace lsst