Modules/ImageProcessor/ImageProcessorTools/MSH2004EdgeDetection.cpp

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/**
* @file Modules/ImageProcessor/ImageProcessorTools/MSH2004EdgeDetection.cpp
* 
* Implementation of MSH2004EdgeDetection.
*
* @author <A href="mailto:sadprofessor@web.de">Bernd Schmidt</A>
*/

#include "MSH2004EdgeDetection.h"
#include "Tools/Location.h"
#include <math.h>

enum{DEFAULT_EDGE_THRESHOLD = 12};

MSH2004EdgeDetection::MSH2004EdgeDetection(RasterImageProcessor& processor)
  :ip(processor),
  susanDetector(processor.edgeDetector),
  threshold(DEFAULT_EDGE_THRESHOLD)
{

}

MSH2004EdgeDetection::~MSH2004EdgeDetection(){
}


bool MSH2004EdgeDetection::scanEast(int& x, int& y){
  if (!insideImage(x,y)) return false;
  int voteBuffer = 0;
  int vote = fastCrossEdgeVote(x,y);
  int x2 = ip.image.cameraInfo.resolutionWidth-1;

  while(x < x2){
    if (vote > threshold || voteBuffer != 0){
      if (voteBuffer < vote) voteBuffer = vote;
      else{
        x--; 
        return true; //edge found (found local maximum)
      }
    }   
    x++;
    vote = fastCrossEdgeVote(x,y);
  }

  if (vote > threshold){
    x--;
    return true; //edgeFound (vote high enough, so found edge on Border)
  }
  else return false; // noEdgeFound
}

bool MSH2004EdgeDetection::scanWest(int& x, int& y){
  if (!insideImage(x,y)) return false;
  int voteBuffer = 0;
  int vote = fastCrossEdgeVote(x,y);

  while(x > 1){
    if (vote > threshold || voteBuffer != 0){
      if (voteBuffer < vote) voteBuffer = vote;
      else{
        x++; 
        return true; //edge found (found local maximum)
      }
    }   
    x--;
    vote = fastCrossEdgeVote(x,y);
  }

  if (vote > threshold){
    x++;
    return true; //edgeFound (vote high enough, so found edge on Border)
  }
  else return false; // noEdgeFound
}
  
bool MSH2004EdgeDetection::scanNorth(int& x, int& y){
  if(!insideImage(x,y)) return false;
  int voteBuffer = 0;
  int vote = fastCrossEdgeVote(x,y);

  while(y > 1){
    if (vote > threshold || voteBuffer != 0){
      if (voteBuffer < vote) voteBuffer = vote;
      else{
        y++; 
        return true; //edge found (found local maximum)
      }
    }   
    y--;
    vote = fastCrossEdgeVote(x,y);
  }

  if (vote > threshold){
    y++;
    return true; //edgeFound (vote high enough, so found edge on Border)
  }
  else return false; // noEdgeFound
}

bool MSH2004EdgeDetection::scanSouth(int& x, int& y){
  if (!insideImage(x,y)) return false;
  int voteBuffer = 0;
  int vote = fastCrossEdgeVote(x,y);
  int y2 = ip.image.cameraInfo.resolutionHeight -2;

  while(y < y2){
    if (vote > threshold || voteBuffer != 0){
      if (voteBuffer < vote) voteBuffer = vote;
      else{
        y--; 
        return true; //edge found (found local maximum)
      }
    }   
    y++;
    vote = fastCrossEdgeVote(x,y);
  }

  if (vote > threshold){
    y--;
    return true; //edgeFound (vote high enough, so found edge on Border)
  }
  else return false; // noEdgeFound
}

bool MSH2004EdgeDetection::ballScanEast(int& x, int& y){
  int voteBuffer = 0;
  int vote = ballEdgeVote(x,y);

  while(vote > -1){
    if (vote > threshold || voteBuffer != 0){
      if (voteBuffer < vote) voteBuffer = vote;
      else{
        x--; 
        return true; //edge found (found local maximum)
      }
    }   
    x++;
    vote = ballEdgeVote(x,y);
  }

  if (vote > threshold){
    x--;
    return true; //edgeFound (vote high enough, so found edge on Border)
  }
  else return false; // noEdgeFound
}

bool MSH2004EdgeDetection::ballScanWest(int& x, int& y){
  int voteBuffer = 0;
  int vote = ballEdgeVote(x,y);

  while(vote > -1){
    if (vote > threshold || voteBuffer != 0){
      if (voteBuffer < vote) voteBuffer = vote;
      else{
        x++; 
        return true; //edge found (found local maximum)
      }
    }   
    x--;
    vote = ballEdgeVote(x,y);
  }

  if (vote > threshold){
    x++;
    return true; //edgeFound (vote high enough, so found edge on Border)
  }
  else return false; // noEdgeFound
}

bool MSH2004EdgeDetection::scan(int& x,int& y,Vector2<double> direction){
  cx = 1;
  cy = 1;

  if (direction.x < 0) cx = -1;
  if (direction.y < 0) cy = -1;

  tempX = x;
  tempY = y;

  int vote = crossEdgeVote(x,y);
  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction

  dx = abs((int)(direction.x * 500));
  dy = abs((int)(direction.y * 500));

  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //setPixel(0,0)
     
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);
      
      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    //setPixel(0,0)

     
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
    }
  }

  if (buffer != 0){
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::bufferedScan(int& x,int& y,Vector2<double> direction){ 
  
  cx = 1;
  cy = 1;

  if (direction.x < 0) cx = -1;
  if (direction.y < 0) cy = -1;

  tempX = x;
  tempY = y;

  int vote = crossEdgeVote(x,y);
  currentColor = lastColor = getColor(x,y);
  bufferSize = 0;

  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction

  dx = abs((int)(direction.x * 500));
  dy = abs((int)(direction.y * 500));

  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //setPixel(0,0)
     
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);
      currentColor = getColor(x,y);
      colorRange++;
      
      if (currentColor != lastColor){
        addColor();
        // there are to many colorChanges between two edge-points
        if (bufferSize > 19) return false;
      } 

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          if (colorRange!=0){
            lastColor = currentColor;
            addColor();
          }
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
      lastColor = currentColor;
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    //setPixel(0,0)

     
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);
      currentColor = getColor(x,y);
      colorRange++;
      
      if (currentColor != lastColor){
        addColor();
        // there are to many colorChanges between two edge-points
        if (bufferSize > 19) return false;
      } 

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          if (colorRange!=0){
            lastColor = currentColor;
            addColor();
          }
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
      lastColor = currentColor;
    }
  }

  if (buffer != 0){
        if (colorRange!=0){
          lastColor = currentColor;
          addColor();
        }
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::bufferedScan(int& x,int& y){ 
  
  currentColor = lastColor = getColor(x,y);
  colorRange = 0;
  bufferSize = 0;

  //skipping 3 pixels, not to detect 1 edge 2 times
  for (int i = 0;i<3;i++){
    skip(x,y);
    currentColor = getColor(x,y);
    colorRange++;
    if (currentColor != lastColor)addColor();
    lastColor = currentColor;
  }
  
  tempX = x;
  tempY = y;

  int vote = crossEdgeVote(x,y);

  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction

  if (dx > dy){    
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);
      currentColor = getColor(x,y);
      colorRange++;
      
      if (currentColor != lastColor){
        addColor();
        // there are to many colorChanges between two edge-points
        if (bufferSize > 19) return false; 
      } 

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          if (colorRange!=0){
            lastColor = currentColor;
            addColor();
          }
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
      lastColor = currentColor;
    }
  }
  else{
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);
      currentColor = getColor(x,y);
      colorRange++;
      
      if (currentColor != lastColor){
        addColor();
      } 

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          if (colorRange!=0){
            lastColor = currentColor;
            addColor();
          }
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
      lastColor = currentColor;
    }
  }

  if (buffer != 0){
        if (colorRange!=0){
          addColor();
        }
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::scanField(int& x,int& y,Vector2<double> direction){
  cx = 1;
  cy = 1;

  if (direction.x < 0) cx = -1;
  if (direction.y < 0) cy = -1;

  tempX = x;
  tempY = y;

  int vote = fieldEdgeVote(x,y);
  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction

  dx = abs((int)(direction.x * 500));
  dy = abs((int)(direction.y * 500));

  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //setPixel(0,0)
     
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = fieldEdgeVote(x,y);
      
      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    //setPixel(0,0)

     
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = fieldEdgeVote(x,y);

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
    }
  }

  if (buffer != 0){
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::scanField(int& x,int& y){

  tempX = x;
  tempY = y;

  int vote = fieldEdgeVote(x,y);
  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction
  if (dx > dy){    
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = fieldEdgeVote(x,y);
      
      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
    }
  }
  else{
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = fieldEdgeVote(x,y);

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }     
      tempX = x;
      tempY = y;
    }
  }

  if (buffer != 0){
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::scan(int& x,int& y,int x1,int y1){
  cx = 1;
  cy = 1;

  dx = x1 - x;
  dy = y1 - y;

  if (dx < 0) cx = -1;
  if (dy < 0) cy = -1;

  tempX = x;
  tempY = y;

  int vote = crossEdgeVote(x,y);
  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction
  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //setPixel(0,0)
     
    for (x+=cx;x<x1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = fastCrossEdgeVote(x,y);
      
      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    //setPixel(0,0)

     
    for (y+=cy;y<y1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = fastCrossEdgeVote(x,y);

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
    }
  }

  if (buffer != 0){
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::colorScan(int& x,int& y,int x1,int y1,colorClass& lastColor){
  cx = 1;
  cy = 1;

  colorClass start = getColor(x,y);
  colorClass current = start;
  
  dx = x1 - x;
  dy = y1 - y;

  if (dx < 0) cx = -1;
  if (dy < 0) cy = -1;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction
  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //TODO(schmidtb): remove inefficient code
    int count = 0; //not to write more code and hold the order
    //setPixel(0,0)
     
    for (x+=cx ; current == start && count < dx ; x+=cx,count++) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      current = getColor(x,y);
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    int count = 0;
    //setPixel(0,0)
    
     
    for (y+=cy; current==start && count<dy; y+=cy,count++) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      current = getColor(x,y);
    }
  }

  if (current == -1){ 
    lastColor = noColor;
    return false;
  }
  else {
    lastColor = start;
    return true;
  }
}

bool MSH2004EdgeDetection::colorScan(int& x,int& y,Vector2<double> direction,colorClass& lastColor){
  cx = 1;
  cy = 1;

  colorClass start = getColor(x,y);
  colorClass current = start;

  if (direction.x < 0) cx = -1;
  if (direction.y < 0) cy = -1;


  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction

  dx = abs((int)(direction.x * 500));
  dy = abs((int)(direction.y * 500));

  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //setPixel(0,0)
     
    for (x+=cx;current == start && current != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      current = getColor(x,y);
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    //setPixel(0,0)

     
    for (y+=cy;current == start && current != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      current = getColor(x,y);
    }
  }

  if (current == -1){ 
    lastColor = noColor;
    return false;
  }
  else {
    lastColor = start;
    return true;
  }
}

bool MSH2004EdgeDetection::colorScan(int& x,int& y,colorClass& lastColor){

  colorClass start = getColor(x,y);
  colorClass current = start;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction
  if (dx > dy){    
    for (x+=cx;current == start && current != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      current = getColor(x,y);
    }
  }
  else{    
    for (y+=cy;current == start && current != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      current = getColor(x,y);
    }
  }

  if (current == -1){ 
    lastColor = noColor;
    return false;
  }
  else {
    lastColor = start;
    return true;
  }
}

bool MSH2004EdgeDetection::susanScan(int& x,int& y,Vector2<double> direction){
  cx = 1;
  cy = 1;

  if (direction.x < 0) cx = -1;
  if (direction.y < 0) cy = -1;

  tempX = x;
  tempY = y;

  int vote = susanVote(x,y);
  int buffer = 0;
  if (vote > 0) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction

  dx = abs((int)(direction.x * 500));
  dy = abs((int)(direction.y * 500));

  if (dx > dy){
    e = dx - 2*dy;
    f = 2*(dx - dy);
    g = -2*dy;
    //setPixel(0,0)
     
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = susanVote(x,y);
      
      if (vote > 0 || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
    }
  }
  else{
    e = dy - 2*dx;
    f = 2*(dy - dx);
    g = -2*dx;
    //setPixel(0,0)

     
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = susanVote(x,y);

      if (vote > 0 || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
    }
  }

  if (buffer != 0){
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

bool MSH2004EdgeDetection::scan(int& x,int& y){

  tempX = x;
  tempY = y;

  int vote = crossEdgeVote(x,y);
  int buffer = 0;
  if (vote > threshold) buffer = vote;

  //doing variation of Bresenham's algorithm for line-drawing, to scan in direction
  if (dx > dy){    
    for (x+=cx;vote != -1;x+=cx) {
      if (e<0) {
        y+=cy;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);
      
      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }

      tempX = x;
      tempY = y;
    }
  }
  else{
    for (y+=cy;vote != -1;y+=cy) {
      if (e<0) {
        x+=cx;
        e+=f;
      }
      else {
        e+=g;
      }
      //setPixel(x,y)
      //DOT(imageProcessor_general,x,y,
      //  Drawings::white, Drawings::red);
      vote = crossEdgeVote(x,y);

      if (vote > threshold || buffer != 0){
        if (buffer < vote) buffer = vote;
        else{
          x = tempX;
          y = tempY;
          return true; //edge found (found local maximum)
        }
      }
      
      tempX = x;
      tempY = y;
    }
  }

  if (buffer != 0){
        x = tempX;
        y = tempY;
        return true; //edge found (found edge on border)
  }

  return false; //no edge found
}

---