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/*
* This file is part of the FORS Data Reduction Pipeline
* Copyright (C) 2002-2010 European Southern Observatory
*
* 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 2 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 GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* vimos_detmodel.cc
*
* Created on: 2014 7 31
* Author: cgarcia
*/
#include <stdexcept>
#include <sstream>
#include "fiera_config.h"
#include "vimos_detmodel.h"
//The detector model is the usual for CCDs: a readout noise component
//and a photon noise component scaled by the gain.
//The readout noise is taken from the overscan region of each readout port
//The gain is taken as the nominal gain from the detector.
//If ccd_config is created with fiera_config(header), the nominal gain
//is taken from the header as ESO DET OUT? GAIN, for instance, also per
//readout port.
cpl_image * vimos_image_variance_from_detmodel(cpl_image * image,
const mosca::ccd_config& ccd_config)
{
//Check that the overscan has not been trimmed:
if(cpl_image_get_size_x(image) != ccd_config.whole_image_npix_x() ||
cpl_image_get_size_y(image) != ccd_config.whole_image_npix_y())
throw std::invalid_argument("Pre/Overscan has already been trimmed. "
"Cannot compute variance for detector");
//Images which contain the model parameters per port
cpl_size im_nx = cpl_image_get_size_x(image);
cpl_size im_ny = cpl_image_get_size_y(image);
cpl_image * ron_sq_im = cpl_image_new(im_nx, im_ny, CPL_TYPE_FLOAT);
cpl_image * gain_im = cpl_image_new(im_nx, im_ny, CPL_TYPE_FLOAT);
cpl_image * os_im = cpl_image_new(im_nx, im_ny, CPL_TYPE_FLOAT);
//Loop on each port:
for(size_t iport = 0; iport < ccd_config.nports(); iport++)
{
mosca::rect_region os_reg =
ccd_config.overscan_region(iport).coord_0to1();
if(os_reg.is_empty())
{
cpl_image_delete(ron_sq_im);
cpl_image_delete(gain_im);
cpl_image_delete(os_im);
throw std::invalid_argument("Overscan area is empty. Cannot compute "
"detector noise model");
}
double ron = ccd_config.computed_ron(iport);
double gain = ccd_config.nominal_gain(iport);
double os_level = cpl_image_get_median_window
(image, os_reg.llx(), os_reg.lly(), os_reg.urx(), os_reg.ury());
mosca::rect_region port_reg =
ccd_config.port_region(iport).coord_0to1();
//TODO: Use cpl_image_fill_window when it exists.
for(cpl_size ix = port_reg.llx(); ix <= port_reg.urx(); ++ix)
for(cpl_size iy = port_reg.lly(); iy <= port_reg.ury(); ++iy)
{
cpl_image_set(ron_sq_im, ix, iy, ron * ron);
cpl_image_set(gain_im, ix, iy, gain);
cpl_image_set(os_im, ix, iy, os_level);
}
}
cpl_image * ima_sub_os = cpl_image_subtract_create(image, os_im);
/* flux_photoel = flux_adu / gain
* poisson_variance_photel = flux_photoel -> Poisson law
* poisson_variance_adu = poisson_variance_photel * gain * gain
* poisson_variance_adu = flux_adu * gain */
cpl_image * poisson_var_adu = cpl_image_multiply_create(ima_sub_os, gain_im);
cpl_image * variance = cpl_image_add_create(poisson_var_adu, ron_sq_im);
cpl_image_delete(ron_sq_im);
cpl_image_delete(gain_im);
cpl_image_delete(os_im);
cpl_image_delete(ima_sub_os);
cpl_image_delete(poisson_var_adu);
return variance;
}
cpl_image * vimos_image_variance_from_detmodel
(cpl_image * image, cpl_propertylist * header, cpl_propertylist * mbias_header)
{
mosca::fiera_config config_ccd(header);
if(mbias_header == NULL)
return NULL;
//Get number of ports
size_t nports = config_ccd.nports();
//Loop on the ports
for(size_t iport = 0; iport < nports; iport++)
{
std::ostringstream key_stream;
key_stream<<"ESO QC DET OUT"<<iport+1<<" RON";
double computed_ron =
cpl_propertylist_get_double(mbias_header,
key_stream.str().c_str());
config_ccd.set_computed_ron(iport, computed_ron);
}
return vimos_image_variance_from_detmodel(image, config_ccd);
}
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