1 | // ----------------------------------------------------------------------- |
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2 | // medianBaseline.cc: Obtaining spectral baselines using a median filter. |
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3 | // ----------------------------------------------------------------------- |
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4 | // Copyright (C) 2006, Matthew Whiting, ATNF |
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5 | // |
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6 | // This program is free software; you can redistribute it and/or modify it |
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7 | // under the terms of the GNU General Public License as published by the |
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8 | // Free Software Foundation; either version 2 of the License, or (at your |
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9 | // option) any later version. |
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10 | // |
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11 | // Duchamp is distributed in the hope that it will be useful, but WITHOUT |
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12 | // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 | // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 | // for more details. |
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15 | // |
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16 | // You should have received a copy of the GNU General Public License |
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17 | // along with Duchamp; if not, write to the Free Software Foundation, |
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18 | // Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA |
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19 | // |
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20 | // Correspondence concerning Duchamp may be directed to: |
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21 | // Internet email: Matthew.Whiting [at] atnf.csiro.au |
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22 | // Postal address: Dr. Matthew Whiting |
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23 | // Australia Telescope National Facility, CSIRO |
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24 | // PO Box 76 |
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25 | // Epping NSW 1710 |
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26 | // AUSTRALIA |
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27 | // ----------------------------------------------------------------------- |
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28 | #include <iostream> |
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29 | #include <map> |
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30 | |
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31 | float medVal(std::map<float,int> &themap) |
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32 | { |
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33 | std::map<float,int>::iterator it; |
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34 | it = themap.begin(); |
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35 | if(themap.size()%2==0) { |
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36 | for(size_t i=0;i<themap.size()/2-1;i++) it++; |
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37 | float v1 = it->first; |
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38 | it++; |
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39 | float v2 = it->first; |
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40 | return (v1+v2)/2.; |
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41 | } |
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42 | else{ |
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43 | for(size_t i=0;i<themap.size()/2;i++) it++; |
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44 | return it->first; |
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45 | } |
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46 | } |
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47 | |
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48 | float *medianBaseline(float *inputArray, int dim, unsigned int boxWidth) |
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49 | { |
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50 | |
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51 | if(boxWidth%2==0) std::cerr << "medianBaseline: boxWidth needs to be odd. Changing from " << boxWidth << " to " << boxWidth+1 <<"\n"; |
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52 | boxWidth++; |
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53 | |
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54 | int halfWidth = boxWidth/2; |
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55 | |
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56 | if(halfWidth > dim) { |
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57 | std::cerr << "Box half-width bigger than array dimension. Returning input array unchanged.\n"; |
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58 | return inputArray; |
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59 | } |
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60 | |
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61 | std::map<float,int> pixMap; |
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62 | |
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63 | float *medianArray = new float[dim]; |
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64 | |
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65 | // Initialise the map for the first point in the array |
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66 | int curpos = 0; |
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67 | for(int i=0; i<=halfWidth; i++) { |
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68 | pixMap.insert(std::pair<float,int>(inputArray[i],i)); |
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69 | // std::cerr << "Inserting " << i << " " << inputArray[i] << "\n"; |
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70 | } |
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71 | medianArray[curpos] = medVal(pixMap); |
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72 | |
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73 | // Do it for the rest of the points |
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74 | curpos++; |
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75 | for(;curpos<dim;curpos++){ |
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76 | |
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77 | int newpix = curpos+halfWidth; |
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78 | if(newpix<dim) pixMap.insert(std::pair<float,int>(inputArray[newpix],newpix)); |
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79 | // std::cerr << "Inserting " << newpix << " " << inputArray[newpix] << "\n"; |
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80 | |
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81 | int oldpix = curpos-halfWidth-1; |
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82 | // if(oldpix>=0) pixMap.erase(oldpix); |
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83 | if(oldpix>=0) pixMap.erase(inputArray[oldpix]); |
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84 | |
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85 | medianArray[curpos] = medVal(pixMap); |
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86 | |
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87 | } |
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88 | |
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89 | return medianArray; |
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90 | } |
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