[301] | 1 | // ----------------------------------------------------------------------- |
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| 2 | // lutz_detect.cc: Search a 2D Image for objects. |
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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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[582] | 28 | #include <duchamp/Detection/finders.hh> |
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[393] | 29 | #include <duchamp/PixelMap/Voxel.hh> |
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| 30 | #include <duchamp/PixelMap/Object2D.hh> |
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[3] | 31 | #include <vector> |
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| 32 | |
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[258] | 33 | using namespace PixelInfo; |
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| 34 | |
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[528] | 35 | /// @brief Enumeration to describe status of a pixel or a detected object |
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[290] | 36 | enum STATUS { NONOBJECT, ///< Pixel not above the threshold. |
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| 37 | OBJECT, ///< Pixel above the threshold. |
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| 38 | COMPLETE, ///< Object is complete |
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| 39 | INCOMPLETE ///< Object not yet complete |
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| 40 | }; |
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| 41 | |
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[528] | 42 | /// @brief Simple enumeration to enable obvious reference to current or prior row. |
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[3] | 43 | enum ROW { PRIOR=0, CURRENT}; |
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| 44 | |
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[528] | 45 | /// @brief A couple of null values: the default starting value for markers, and one used for debugging. |
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[290] | 46 | enum NULLS { NULLSTART=-1, ///< Default start/end value, obviously |
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| 47 | /// outside valid range. |
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| 48 | NULLMARKER=45 ///< ASCII 45 = '-', which eases printing |
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| 49 | /// for debugging purposes |
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| 50 | }; |
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| 51 | |
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[258] | 52 | //--------------------------- |
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[528] | 53 | /// @brief |
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[582] | 54 | /// A simple class local to @file to help manage detected |
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[528] | 55 | /// objects. |
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| 56 | /// |
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| 57 | /// @details Keeps a track of a detection, as well as the start and finish |
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| 58 | /// locations of the detection on the current row. |
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| 59 | /// |
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[258] | 60 | class FoundObject{ |
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[3] | 61 | public: |
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[528] | 62 | /// @brief Basic constructor, setting the start & end to NULL values. |
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[258] | 63 | FoundObject(){start=NULLSTART; end=NULLSTART;}; |
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[222] | 64 | int start; ///< Pixel on the current row where the detection starts. |
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| 65 | int end; ///< Pixel on the current row where the detection finishes. |
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[258] | 66 | Object2D info; ///< Collection of detected pixels. |
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[3] | 67 | }; |
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[258] | 68 | //--------------------------- |
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[3] | 69 | |
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[378] | 70 | namespace duchamp |
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[3] | 71 | { |
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[222] | 72 | |
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[1008] | 73 | std::vector<Object2D> lutz_detect(std::vector<bool> &array, size_t xdim, size_t ydim, unsigned int minSize) |
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[378] | 74 | { |
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[528] | 75 | /// @details |
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| 76 | /// A detection algorithm for 2-dimensional images based on that of |
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| 77 | /// Lutz (1980). |
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| 78 | /// |
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| 79 | /// The image is raster-scanned, and searched row-by-row. Objects |
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| 80 | /// detected in each row are compared to objects in subsequent rows, |
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| 81 | /// and combined if they are connected (in an 8-fold sense). |
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| 82 | /// |
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[3] | 83 | |
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[378] | 84 | // Allocate necessary arrays. |
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| 85 | std::vector<Object2D> outputlist; |
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| 86 | STATUS *status = new STATUS[2]; |
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[582] | 87 | Object2D *store = new Object2D[xdim+1]; |
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[627] | 88 | char *marker = new char[xdim+1]; |
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[1008] | 89 | for(size_t i=0; i<(xdim+1); i++) marker[i] = NULLMARKER; |
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[378] | 90 | std::vector<FoundObject> oS; |
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| 91 | std::vector<STATUS> psS; |
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[3] | 92 | |
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[655] | 93 | size_t loc=0; |
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[378] | 94 | |
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[1008] | 95 | for(size_t posY=0;posY<(ydim+1);posY++){ |
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[378] | 96 | // Loop over each row -- consider rows one at a time |
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[3] | 97 | |
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[378] | 98 | status[PRIOR] = COMPLETE; |
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| 99 | status[CURRENT] = NONOBJECT; |
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[3] | 100 | |
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[1008] | 101 | for(size_t posX=0;posX<(xdim+1);posX++){ |
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[378] | 102 | // Now the loop for a given row, looking at each column individually. |
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[3] | 103 | |
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[378] | 104 | char currentMarker = marker[posX]; |
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| 105 | marker[posX] = NULLMARKER; |
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[3] | 106 | |
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[378] | 107 | bool isObject; |
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[582] | 108 | if((posX<xdim)&&(posY<ydim)){ |
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[378] | 109 | // if we are in the original image |
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[655] | 110 | isObject = array[loc++]; |
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[378] | 111 | } |
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| 112 | else isObject = false; |
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| 113 | // else we're in the padding row/col and isObject=FALSE; |
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[3] | 114 | |
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[378] | 115 | // |
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| 116 | // ------------------------------ START SEGMENT ------------------------ |
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| 117 | // If the current pixel is object and the previous pixel is not, then |
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| 118 | // start a new segment. |
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| 119 | // If the pixel touches an object on the prior row, the marker is either |
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| 120 | // an S or an s, depending on whether the object has started yet. |
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| 121 | // If it doesn't touch a prior object, this is the start of a completly |
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| 122 | // new object on this row. |
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| 123 | // |
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| 124 | if ( (isObject) && (status[CURRENT] != OBJECT) ){ |
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[3] | 125 | |
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[378] | 126 | status[CURRENT] = OBJECT; |
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| 127 | if(status[PRIOR] == OBJECT){ |
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[3] | 128 | |
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[378] | 129 | if(oS.back().start==NULLSTART){ |
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| 130 | marker[posX] = 'S'; |
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[1009] | 131 | oS.back().start = int(posX); |
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[378] | 132 | } |
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| 133 | else marker[posX] = 's'; |
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| 134 | } |
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| 135 | else{ |
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| 136 | psS.push_back(status[PRIOR]); //PUSH PS onto PSSTACK; |
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[3] | 137 | marker[posX] = 'S'; |
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[378] | 138 | oS.resize(oS.size()+1); //PUSH OBSTACK; |
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[1009] | 139 | oS.back().start = int(posX); |
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[378] | 140 | |
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| 141 | status[PRIOR] = COMPLETE; |
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[3] | 142 | } |
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| 143 | } |
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| 144 | |
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[378] | 145 | // |
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| 146 | // ------------------------------ PROCESS MARKER ----------------------- |
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| 147 | // If the current marker is not blank, then we need to deal with it. |
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| 148 | // Four cases: |
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| 149 | // S --> start of object on prior row. Push priorStatus onto PSSTACK |
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| 150 | // and set priorStatus to OBJECT |
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| 151 | // s --> start of a secondary segment of object on prior row. |
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| 152 | // If current object joined, pop PSSTACK and join the objects. |
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| 153 | // Set priorStatus to OBJECT. |
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| 154 | // f --> end of a secondary segment of object on prior row. |
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| 155 | // Set priorStatus to INCOMPLETE. |
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| 156 | // F --> end of object on prior row. If no more of the object is to |
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| 157 | // come (priorStatus=COMPLETE), then finish it and output data. |
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| 158 | // Add to list, but only if it has more than the minimum number |
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| 159 | // of pixels. |
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| 160 | // |
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| 161 | if(currentMarker != NULLMARKER){ |
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[3] | 162 | |
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[378] | 163 | if(currentMarker == 'S'){ |
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| 164 | psS.push_back(status[PRIOR]); // PUSH PS onto PSSTACK |
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| 165 | if(status[CURRENT] == NONOBJECT){ |
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| 166 | psS.push_back(COMPLETE); // PUSH COMPLETE ONTO PSSTACK; |
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| 167 | oS.resize(oS.size()+1); // PUSH OBSTACK; |
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| 168 | oS.back().info = store[posX]; |
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| 169 | } |
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| 170 | else oS.back().info = oS.back().info + store[posX]; |
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| 171 | |
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| 172 | status[PRIOR] = OBJECT; |
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[3] | 173 | } |
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| 174 | |
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[378] | 175 | /*---------*/ |
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| 176 | if(currentMarker == 's'){ |
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[3] | 177 | |
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[378] | 178 | if( (status[CURRENT] == OBJECT) && (status[PRIOR] == COMPLETE) ){ |
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| 179 | status[PRIOR] = psS.back(); |
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| 180 | psS.pop_back(); //POP PSSTACK ONTO PS |
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[3] | 181 | |
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[378] | 182 | // oS.at(oS.size()-2).info.addAnObject( oS.back().info ); |
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| 183 | // if(oS.at(oS.size()-2).start == NULLSTART) |
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| 184 | // oS.at(oS.size()-2).start = oS.back().start; |
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| 185 | // else marker[oS.back().start] = 's'; |
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[3] | 186 | |
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[378] | 187 | oS[oS.size()-2].info = oS[oS.size()-2].info + oS.back().info; |
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| 188 | if(oS[oS.size()-2].start == NULLSTART) |
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| 189 | oS[oS.size()-2].start = oS.back().start; |
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| 190 | else marker[oS.back().start] = 's'; |
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[258] | 191 | |
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[378] | 192 | oS.pop_back(); |
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| 193 | } |
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| 194 | |
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| 195 | status[PRIOR] = OBJECT; |
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[3] | 196 | } |
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| 197 | |
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[378] | 198 | /*---------*/ |
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| 199 | if(currentMarker == 'f') status[PRIOR] = INCOMPLETE; |
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[3] | 200 | |
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[378] | 201 | /*---------*/ |
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| 202 | if(currentMarker == 'F') { |
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[3] | 203 | |
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[378] | 204 | status[PRIOR] = psS.back(); |
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| 205 | psS.pop_back(); //POP PSSTACK ONTO PS |
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[3] | 206 | |
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[378] | 207 | if( (status[CURRENT] == NONOBJECT) && (status[PRIOR] == COMPLETE) ){ |
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[3] | 208 | |
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[378] | 209 | if(oS.back().start == NULLSTART){ |
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| 210 | // The object is completed. If it is big enough, add to |
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| 211 | // the end of the output list. |
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[582] | 212 | if(oS.back().info.getSize() >= minSize){ |
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[378] | 213 | //oS.back().info.calcParams(); // work out midpoints, fluxes etc |
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| 214 | outputlist.push_back(oS.back().info); |
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| 215 | } |
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| 216 | } |
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| 217 | else{ |
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| 218 | marker[ oS.back().end ] = 'F'; |
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| 219 | store[ oS.back().start ] = oS.back().info; |
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| 220 | } |
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[3] | 221 | |
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[378] | 222 | oS.pop_back(); |
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| 223 | |
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| 224 | status[PRIOR] = psS.back(); |
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| 225 | psS.pop_back(); |
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[3] | 226 | } |
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[378] | 227 | } |
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[3] | 228 | |
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[378] | 229 | } // end of PROCESSMARKER section ( if(currentMarker!=NULLMARKER) ) |
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[3] | 230 | |
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[378] | 231 | if (isObject){ |
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[1008] | 232 | oS.back().info.addPixel(long(posX),long(posY)); |
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[3] | 233 | } |
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[378] | 234 | else{ |
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| 235 | // |
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| 236 | // ----------------------------- END SEGMENT ------------------------- |
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| 237 | // If the current pixel is background and the previous pixel was an |
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| 238 | // object, then finish the segment. |
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| 239 | // If the prior status is COMPLETE, it's the end of the final segment |
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| 240 | // of the object section. |
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| 241 | // If not, it's end of the segment, but not necessarily the section. |
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| 242 | // |
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| 243 | if ( status[CURRENT] == OBJECT) { |
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[3] | 244 | |
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[378] | 245 | status[CURRENT] = NONOBJECT; |
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[3] | 246 | |
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[378] | 247 | if(status[PRIOR] != COMPLETE){ |
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| 248 | marker[posX] = 'f'; |
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[1009] | 249 | oS.back().end = int(posX); |
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[378] | 250 | } |
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| 251 | else{ |
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| 252 | status[PRIOR] = psS.back(); |
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| 253 | psS.pop_back(); //POP PSSTACK onto PS; |
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| 254 | marker[posX] = 'F'; |
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| 255 | store[ oS.back().start ] = oS.back().info; |
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| 256 | oS.pop_back(); |
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| 257 | } |
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[3] | 258 | } |
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| 259 | |
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[378] | 260 | } //-> end of END SEGMENT else{ clause |
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[3] | 261 | |
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[378] | 262 | }//-> end of loop over posX |
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[3] | 263 | |
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[378] | 264 | }//-> end of loop over posY |
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[3] | 265 | |
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[378] | 266 | // clean up and remove declared arrays |
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| 267 | delete [] marker; |
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| 268 | delete [] store; |
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| 269 | delete [] status; |
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[3] | 270 | |
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[378] | 271 | return outputlist; |
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[258] | 272 | |
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[378] | 273 | } |
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| 274 | |
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[3] | 275 | } |
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