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/* $Id: irplib_ksigma_clip_body.h,v 1.1 2011-11-02 13:18:28 amodigli Exp $
*
* This file is part of the irplib package
* Copyright (C) 2002,2003 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 02111-1307 USA
*/
/*
* $Author: amodigli $
* $Date: 2011-11-02 13:18:28 $
* $Revision: 1.1 $
* $Name: not supported by cvs2svn $
*/
#define TYPE_ADD(a) CONCAT2X(a, CPL_TYPE)
static cpl_error_code
TYPE_ADD(irplib_ksigma_clip)(const CPL_TYPE * pi,
int llx,
int lly,
int urx,
int ury,
int nx,
double var_sum,
int npixs,
double kappa,
int nclip,
double tolerance,
double * mean,
double * stdev)
{
int pos0 = (llx - 1) + (lly - 1) * nx; /* 1st pixel to process */
double nb = (double) npixs; /* Non-bad pixels in window */
double lo_cut = *mean - kappa * (*stdev);
double hi_cut = *mean + kappa * (*stdev);
double lo_cut_p = lo_cut;
double hi_cut_p = hi_cut;
double c_mean = 0; /* Set to zero in case loop body not executed. */
double c_stdev = 0; /* Set to zero in case loop body not executed. */
int iclip;
for (iclip = 0; iclip < nclip; iclip++) {
int pos = pos0;
int i, j;
double c_var_sum;
c_var_sum = var_sum;
c_mean = *mean;
c_stdev = *stdev;
nb = npixs;
for (j = lly - 1; j < ury; j++, pos += (nx - urx + llx - 1)) {
for (i = llx - 1; i < urx; i++, pos++) {
if (pi[pos] > hi_cut || pi[pos] < lo_cut) {
const double delta = (double)pi[pos] - c_mean;
c_var_sum -= nb * delta * delta / (nb - 1.0);
c_mean -= delta / (nb - 1.0);
nb = nb - 1.0;
}
}
}
if (nb == 1.0 || c_var_sum < 0.0) {
cpl_msg_error(cpl_func, "Iteration %d: Too many pixels were "
"removed. This may cause unexpected behaviour. "
"Please set a lower number of iterations "
"or increase the value of kappa\n", iclip);
cpl_error_set(cpl_func, CPL_ERROR_DIVISION_BY_ZERO);
} else {
c_stdev = sqrt(c_var_sum / (nb - 1.0));
}
lo_cut = c_mean - kappa * c_stdev;
hi_cut = c_mean + kappa * c_stdev;
if(fabs(lo_cut - lo_cut_p) < tolerance &&
fabs(hi_cut - hi_cut_p) < tolerance) {
break;
} else {
lo_cut_p = lo_cut;
hi_cut_p = hi_cut;
}
}
*mean = c_mean;
*stdev = c_stdev;
return cpl_error_get_code();
}
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