source: trunk/src/Detection/lutz_detect.cc @ 232

#include <Cubes/cubes.hh>
#include <Detection/detection.hh>
#include <vector>

enum STATUS { NONOBJECT, OBJECT, COMPLETE, INCOMPLETE };
enum ROW { PRIOR=0, CURRENT};
enum NULLS { NULLSTART=-1, NULLMARKER=45}; //ASCII 45 = '-' --> eases printing in case of debugging

/**
 * Local class to manage locating detections.
 * Keeps a track of a detection, as well as the start and finish
 * locations of the detection on the current row.
 */
class Object{
public:
  Object(){start=NULLSTART; end=NULLSTART;};
  int start; ///< Pixel on the current row where the detection starts.
  int end;   ///< Pixel on the current row where the detection finishes.
  Detection info; ///< Collection of detected pixels.
};

void Image::lutz_detect() 
{
/**
 *  A detection algorithm for 2-dimensional images based on that of
 *  Lutz (1980).
 *  
 *  The image is raster-scanned, and searched row-by-row. Objects
 *  detected in each row are compared to objects in subsequent rows,
 *  and combined if they are connected (in an 8-fold sense).
 * 
 *  Note that "detected" here means according to the
 *  Image::isDetection(long,long) function.
 *
 *  Upon return, the detected objects are stored in the
 *  Image::objectList vector.
 *
 */

  // Allocate necessary arrays.
  STATUS *status   = new STATUS[2];
  Detection *store = new Detection[this->axisDim[0]+1];
  char *marker     = new char[this->axisDim[0]+1];
  for(int i=0; i<(this->axisDim[0]+1); i++) marker[i] = NULLMARKER;
  std::vector<Object>  *oS    = new std::vector<Object>;
  std::vector<STATUS> *psS    = new std::vector<STATUS>;

  Pixel *pix = new Pixel;

  for(int posY=0;posY<(this->axisDim[1]+1);posY++){
    // Loop over each row -- consider rows one at a time
    
    status[PRIOR] = COMPLETE;
    status[CURRENT] = NONOBJECT;

    pix->setY(posY);

    for(int posX=0;posX<(this->axisDim[0]+1);posX++){
      // Now the loop for a given row, looking at each column individually.

      char currentMarker = marker[posX];
      marker[posX] = NULLMARKER;
      pix->setX(posX);

      bool isObject = false;
      if((posX<this->axisDim[0])&&(posY<this->axisDim[1])){ 
        // if we are in the original image
        isObject = this->isDetection(posX,posY);
        pix->setF( this->array[posY*this->axisDim[0] + posX] );
      }
      // else we're in the padding row/col and isObject=FALSE;

      // 
      // ------------------------------ START SEGMENT ------------------------
      // If the current pixel is object and the previous pixel is not, then
      // start a new segment.
      // If the pixel touches an object on the prior row, the marker is either
      // an S or an s, depending on whether the object has started yet.
      // If it doesn't touch a prior object, this is the start of a completly
      // new object on this row.
      // 
      if ( (isObject) && (status[CURRENT] != OBJECT) ){

        status[CURRENT] = OBJECT;
        if(status[PRIOR] == OBJECT){
          
          if(oS->back().start==NULLSTART){
            marker[posX] = 'S';
            oS->back().start = posX;
          }
          else  marker[posX] = 's';
        }
        else{
          psS->push_back(status[PRIOR]);  //PUSH PS onto PSSTACK;
          marker[posX] = 'S';
          oS->resize(oS->size()+1);        //PUSH OBSTACK;
          oS->back().start = posX;

          status[PRIOR] = COMPLETE;
        }
      }

      // 
      // ------------------------------ PROCESS MARKER -----------------------
      // If the current marker is not blank, then we need to deal with it. 
      // Four cases:
      //   S --> start of object on prior row. Push priorStatus onto PSSTACK 
      //         and set priorStatus to OBJECT
      //   s --> start of a secondary segment of object on prior row.
      //         If current object joined, pop PSSTACK and join the objects.
      //         Set priorStatus to OBJECT.
      //   f --> end of a secondary segment of object on prior row.
      //         Set priorStatus to INCOMPLETE.
      //   F --> end of object on prior row. If no more of the object is to 
      //          come (priorStatus=COMPLETE), then finish it and output data.
      //         Add to list, but only if it has more than the minimum number
      //           of pixels.
      // 
      if(currentMarker != NULLMARKER){

        if(currentMarker == 'S'){
          psS->push_back(status[PRIOR]);      // PUSH PS onto PSSTACK
          if(status[CURRENT] == NONOBJECT){
            psS->push_back(COMPLETE);         // PUSH COMPLETE ONTO PSSTACK;
            oS->resize(oS->size()+1);          // PUSH OBSTACK;
            oS->back().info = store[posX];
          }
          else oS->back().info.addAnObject( store[posX] );
          
          status[PRIOR] = OBJECT;
        }

        /*---------*/
        if(currentMarker == 's'){

          if( (status[CURRENT] == OBJECT) && (status[PRIOR] == COMPLETE) ){
            status[PRIOR] = psS->back();
            psS->pop_back();                   //POP PSSTACK ONTO PS

//          oS->at(oS->size()-2).info.addAnObject( oS->back().info );
//          if(oS->at(oS->size()-2).start == NULLSTART) oS->at(oS->size()-2).start = oS->back().start;
//          else marker[oS->back().start] = 's';
            (*oS)[oS->size()-2].info.addAnObject( oS->back().info );
            if((*oS)[oS->size()-2].start == NULLSTART) 
              (*oS)[oS->size()-2].start = oS->back().start;
            else marker[oS->back().start] = 's';

            oS->pop_back();
          }

          status[PRIOR] = OBJECT;
        }

        /*---------*/
        if(currentMarker == 'f') status[PRIOR] = INCOMPLETE;

        /*---------*/
        if(currentMarker == 'F') {

          status[PRIOR] = psS->back();
          psS->pop_back();                    //POP PSSTACK ONTO PS

          if( (status[CURRENT] == NONOBJECT) && (status[PRIOR] == COMPLETE) ){

            if(oS->back().start == NULLSTART){ // object completed
              if(oS->back().info.getSize() >= this->minSize){ 
                // is it big enough?
                oS->back().info.calcParams(); // work out midpoints, fluxes etc
                this->addObject(oS->back().info);
              }
            }
            else{
              marker[ oS->back().end ] = 'F';
              store[ oS->back().start ] = oS->back().info;
            }

            oS->pop_back();

            status[PRIOR] = psS->back();
            psS->pop_back();
          }
        }

      } // end of PROCESSMARKER section ( if(currentMarker!=NULLMARKER) )

      if (isObject){
        oS->back().info.addPixel(*pix);
      }
      else{
        // 
        // ----------------------------- END SEGMENT -------------------------
        // If the current pixel is background and the previous pixel was an 
        // object, then finish the segment.
        // If the prior status is COMPLETE, it's the end of the final segment 
        // of the object section.
        // If not, it's end of the segment, but not necessarily the section.
        // 
        if ( status[CURRENT] == OBJECT) {

          status[CURRENT] = NONOBJECT;

          if(status[PRIOR] != COMPLETE){
            marker[posX] = 'f';
            oS->back().end = posX;
          }
          else{
            status[PRIOR] = psS->back();
            psS->pop_back();                   //POP PSSTACK onto PS;
            marker[posX] = 'F';
            store[ oS->back().start ] = oS->back().info;
            oS->pop_back();
          }
        }
        
      } //-> end of END SEGMENT else{ clause

    }//-> end of loop over posX

  }//-> end of loop over posY

  // clean up and remove declared arrays
  delete [] marker;
  delete oS;
  delete psS;
  delete [] store;
  delete [] status;
  delete pix; 

}