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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28 | #include <duchamp/Cubes/cubes.hh> |
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29 | #include <duchamp/PixelMap/Voxel.hh> |
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30 | #include <duchamp/PixelMap/Object2D.hh> |
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31 | #include <vector> |
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32 | |
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33 | using namespace PixelInfo; |
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34 | |
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35 | /** Enumeration to describe status of a pixel or a detected object */ |
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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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42 | /** Simple enumeration to enable obvious reference to current or prior |
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43 | row. */ |
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44 | enum ROW { PRIOR=0, CURRENT}; |
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45 | |
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46 | /** A couple of null values: the default starting value for markers, |
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47 | and one used for debugging. */ |
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48 | enum NULLS { NULLSTART=-1, ///< Default start/end value, obviously |
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49 | /// outside valid range. |
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50 | NULLMARKER=45 ///< ASCII 45 = '-', which eases printing |
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51 | /// for debugging purposes |
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52 | }; |
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53 | |
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54 | //--------------------------- |
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55 | /** |
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56 | * A simple class local to lutz_detect.cc to help manage detected |
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57 | * objects. |
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58 | * |
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59 | * Keeps a track of a detection, as well as the start and finish |
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60 | * locations of the detection on the current row. |
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61 | */ |
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62 | class FoundObject{ |
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63 | public: |
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64 | /** Basic constructor, setting the start & end to NULL values. */ |
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65 | FoundObject(){start=NULLSTART; end=NULLSTART;}; |
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66 | int start; ///< Pixel on the current row where the detection starts. |
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67 | int end; ///< Pixel on the current row where the detection finishes. |
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68 | Object2D info; ///< Collection of detected pixels. |
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69 | }; |
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70 | //--------------------------- |
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71 | |
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72 | namespace duchamp |
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73 | { |
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74 | |
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75 | std::vector<Object2D> Image::lutz_detect() |
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76 | { |
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77 | /** |
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78 | * A detection algorithm for 2-dimensional images based on that of |
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79 | * Lutz (1980). |
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80 | * |
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81 | * The image is raster-scanned, and searched row-by-row. Objects |
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82 | * detected in each row are compared to objects in subsequent rows, |
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83 | * and combined if they are connected (in an 8-fold sense). |
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84 | * |
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85 | * Note that "detected" here means according to the |
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86 | * Image::isDetection(long,long) function. |
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87 | * |
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88 | * Upon return, the detected objects are stored in the |
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89 | * Image::objectList vector. |
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90 | * |
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91 | */ |
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92 | |
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93 | // Allocate necessary arrays. |
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94 | std::vector<Object2D> outputlist; |
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95 | STATUS *status = new STATUS[2]; |
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96 | Object2D *store = new Object2D[this->axisDim[0]+1]; |
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97 | char *marker = new char[this->axisDim[0]+1]; |
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98 | for(int i=0; i<(this->axisDim[0]+1); i++) marker[i] = NULLMARKER; |
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99 | std::vector<FoundObject> oS; |
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100 | std::vector<STATUS> psS; |
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101 | |
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102 | Pixel pix; |
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103 | |
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104 | for(int posY=0;posY<(this->axisDim[1]+1);posY++){ |
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105 | // Loop over each row -- consider rows one at a time |
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106 | |
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107 | status[PRIOR] = COMPLETE; |
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108 | status[CURRENT] = NONOBJECT; |
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109 | |
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110 | for(int posX=0;posX<(this->axisDim[0]+1);posX++){ |
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111 | // Now the loop for a given row, looking at each column individually. |
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112 | |
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113 | char currentMarker = marker[posX]; |
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114 | marker[posX] = NULLMARKER; |
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115 | |
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116 | bool isObject; |
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117 | if((posX<this->axisDim[0])&&(posY<this->axisDim[1])){ |
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118 | // if we are in the original image |
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119 | isObject = this->isDetection(posX,posY); |
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120 | } |
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121 | else isObject = false; |
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122 | // else we're in the padding row/col and isObject=FALSE; |
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123 | |
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124 | // |
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125 | // ------------------------------ START SEGMENT ------------------------ |
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126 | // If the current pixel is object and the previous pixel is not, then |
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127 | // start a new segment. |
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128 | // If the pixel touches an object on the prior row, the marker is either |
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129 | // an S or an s, depending on whether the object has started yet. |
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130 | // If it doesn't touch a prior object, this is the start of a completly |
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131 | // new object on this row. |
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132 | // |
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133 | if ( (isObject) && (status[CURRENT] != OBJECT) ){ |
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134 | |
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135 | status[CURRENT] = OBJECT; |
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136 | if(status[PRIOR] == OBJECT){ |
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137 | |
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138 | if(oS.back().start==NULLSTART){ |
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139 | marker[posX] = 'S'; |
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140 | oS.back().start = posX; |
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141 | } |
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142 | else marker[posX] = 's'; |
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143 | } |
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144 | else{ |
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145 | psS.push_back(status[PRIOR]); //PUSH PS onto PSSTACK; |
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146 | marker[posX] = 'S'; |
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147 | oS.resize(oS.size()+1); //PUSH OBSTACK; |
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148 | oS.back().start = posX; |
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149 | |
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150 | status[PRIOR] = COMPLETE; |
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151 | } |
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152 | } |
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153 | |
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154 | // |
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155 | // ------------------------------ PROCESS MARKER ----------------------- |
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156 | // If the current marker is not blank, then we need to deal with it. |
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157 | // Four cases: |
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158 | // S --> start of object on prior row. Push priorStatus onto PSSTACK |
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159 | // and set priorStatus to OBJECT |
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160 | // s --> start of a secondary segment of object on prior row. |
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161 | // If current object joined, pop PSSTACK and join the objects. |
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162 | // Set priorStatus to OBJECT. |
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163 | // f --> end of a secondary segment of object on prior row. |
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164 | // Set priorStatus to INCOMPLETE. |
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165 | // F --> end of object on prior row. If no more of the object is to |
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166 | // come (priorStatus=COMPLETE), then finish it and output data. |
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167 | // Add to list, but only if it has more than the minimum number |
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168 | // of pixels. |
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169 | // |
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170 | if(currentMarker != NULLMARKER){ |
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171 | |
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172 | if(currentMarker == 'S'){ |
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173 | psS.push_back(status[PRIOR]); // PUSH PS onto PSSTACK |
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174 | if(status[CURRENT] == NONOBJECT){ |
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175 | psS.push_back(COMPLETE); // PUSH COMPLETE ONTO PSSTACK; |
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176 | oS.resize(oS.size()+1); // PUSH OBSTACK; |
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177 | oS.back().info = store[posX]; |
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178 | } |
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179 | else oS.back().info = oS.back().info + store[posX]; |
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180 | |
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181 | status[PRIOR] = OBJECT; |
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182 | } |
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183 | |
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184 | /*---------*/ |
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185 | if(currentMarker == 's'){ |
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186 | |
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187 | if( (status[CURRENT] == OBJECT) && (status[PRIOR] == COMPLETE) ){ |
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188 | status[PRIOR] = psS.back(); |
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189 | psS.pop_back(); //POP PSSTACK ONTO PS |
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190 | |
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191 | // oS.at(oS.size()-2).info.addAnObject( oS.back().info ); |
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192 | // if(oS.at(oS.size()-2).start == NULLSTART) |
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193 | // oS.at(oS.size()-2).start = oS.back().start; |
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194 | // else marker[oS.back().start] = 's'; |
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195 | |
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196 | oS[oS.size()-2].info = oS[oS.size()-2].info + oS.back().info; |
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197 | if(oS[oS.size()-2].start == NULLSTART) |
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198 | oS[oS.size()-2].start = oS.back().start; |
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199 | else marker[oS.back().start] = 's'; |
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200 | |
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201 | oS.pop_back(); |
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202 | } |
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203 | |
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204 | status[PRIOR] = OBJECT; |
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205 | } |
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206 | |
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207 | /*---------*/ |
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208 | if(currentMarker == 'f') status[PRIOR] = INCOMPLETE; |
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209 | |
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210 | /*---------*/ |
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211 | if(currentMarker == 'F') { |
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212 | |
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213 | status[PRIOR] = psS.back(); |
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214 | psS.pop_back(); //POP PSSTACK ONTO PS |
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215 | |
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216 | if( (status[CURRENT] == NONOBJECT) && (status[PRIOR] == COMPLETE) ){ |
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217 | |
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218 | if(oS.back().start == NULLSTART){ |
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219 | // The object is completed. If it is big enough, add to |
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220 | // the end of the output list. |
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221 | if(oS.back().info.getSize() >= this->minSize){ |
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222 | //oS.back().info.calcParams(); // work out midpoints, fluxes etc |
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223 | outputlist.push_back(oS.back().info); |
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224 | } |
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225 | } |
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226 | else{ |
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227 | marker[ oS.back().end ] = 'F'; |
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228 | store[ oS.back().start ] = oS.back().info; |
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229 | } |
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230 | |
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231 | oS.pop_back(); |
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232 | |
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233 | status[PRIOR] = psS.back(); |
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234 | psS.pop_back(); |
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235 | } |
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236 | } |
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237 | |
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238 | } // end of PROCESSMARKER section ( if(currentMarker!=NULLMARKER) ) |
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239 | |
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240 | if (isObject){ |
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241 | oS.back().info.addPixel(posX,posY); |
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242 | } |
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243 | else{ |
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244 | // |
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245 | // ----------------------------- END SEGMENT ------------------------- |
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246 | // If the current pixel is background and the previous pixel was an |
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247 | // object, then finish the segment. |
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248 | // If the prior status is COMPLETE, it's the end of the final segment |
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249 | // of the object section. |
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250 | // If not, it's end of the segment, but not necessarily the section. |
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251 | // |
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252 | if ( status[CURRENT] == OBJECT) { |
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253 | |
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254 | status[CURRENT] = NONOBJECT; |
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255 | |
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256 | if(status[PRIOR] != COMPLETE){ |
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257 | marker[posX] = 'f'; |
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258 | oS.back().end = posX; |
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259 | } |
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260 | else{ |
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261 | status[PRIOR] = psS.back(); |
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262 | psS.pop_back(); //POP PSSTACK onto PS; |
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263 | marker[posX] = 'F'; |
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264 | store[ oS.back().start ] = oS.back().info; |
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265 | oS.pop_back(); |
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266 | } |
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267 | } |
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268 | |
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269 | } //-> end of END SEGMENT else{ clause |
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270 | |
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271 | }//-> end of loop over posX |
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272 | |
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273 | }//-> end of loop over posY |
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274 | |
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275 | // clean up and remove declared arrays |
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276 | delete [] marker; |
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277 | delete [] store; |
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278 | delete [] status; |
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279 | |
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280 | return outputlist; |
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281 | |
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282 | } |
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283 | |
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284 | } |
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