median_filter.cc

00001 /*
00002  *  This file is part of Healpix_cxx.
00003  *
00004  *  Healpix_cxx is free software; you can redistribute it and/or modify
00005  *  it under the terms of the GNU General Public License as published by
00006  *  the Free Software Foundation; either version 2 of the License, or
00007  *  (at your option) any later version.
00008  *
00009  *  Healpix_cxx is distributed in the hope that it will be useful,
00010  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00011  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00012  *  GNU General Public License for more details.
00013  *
00014  *  You should have received a copy of the GNU General Public License
00015  *  along with Healpix_cxx; if not, write to the Free Software
00016  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00017  *
00018  *  For more information about HEALPix, see http://healpix.jpl.nasa.gov
00019  */
00020 
00021 /*
00022  *  Healpix_cxx is being developed at the Max-Planck-Institut fuer Astrophysik
00023  *  and financially supported by the Deutsches Zentrum fuer Luft- und Raumfahrt
00024  *  (DLR).
00025  */
00026 
00027 /*
00028  *  Copyright (C) 2005 Max-Planck-Society
00029  *  Author: Martin Reinecke
00030  */
00031 
00032 #include "cxxutils.h"
00033 #include "healpix_map.h"
00034 #include "healpix_map_fitsio.h"
00035 #include "fitshandle.h"
00036 
00037 using namespace std;
00038 
00039 template<typename Iterator> typename iterator_traits<Iterator>::value_type
00040   median(Iterator first, Iterator last)
00041   {
00042   Iterator mid = first+(last-first-1)/2;
00043   nth_element(first,mid,last);
00044   if ((last-first)&1) return *mid;
00045   return 0.5*((*mid)+(*min_element(mid+1,last)));
00046   }
00047 
00048 int main (int argc, const char **argv)
00049   {
00050   module_startup ("median_filter", argc, argv, 4,
00051                   "<input map> <output map> <radius in arcmin>");
00052 
00053   double radius = stringToData<double>(argv[3])/60*degr2rad;
00054 
00055   Healpix_Map<float> inmap;
00056   read_Healpix_map_from_fits(argv[1],inmap,1,2);
00057   Healpix_Map<float> outmap (inmap.Nside(), inmap.Scheme(), SET_NSIDE);
00058 
00059   vector<int> list;
00060   vector<float> list2;
00061   for (int m=0; m<inmap.Npix(); ++m)
00062     {
00063     inmap.query_disc(inmap.pix2ang(m),radius,list);
00064     list2.resize(list.size());
00065     for (unsigned int i=0; i<list.size(); ++i)
00066       list2[i] = inmap[list[i]];
00067     outmap[m]=median(list2.begin(),list2.end());
00068     }
00069 
00070   fitshandle out;
00071   out.create(argv[2]);
00072   write_Healpix_map_to_fits (out,outmap,TFLOAT);
00073   }