Assigning coordinates of a point to another OpenCV C + +

Question

I did the translation of contour points (about 300-1000 points) i.e. each point I changed its X and Y coordinates to move the center of vector XOY to the center of gravity with this formula:

vector<vector<Point> > contours_poly( contours.size() ); 
vector<vector<Point> > contours( contours.size() ); 
for(unsigned int i=0;i<contours.size();i++)
  {
  approxPolyDP( Mat(contours[i]), contours_poly[i], 2, true );
    convexHull( Mat(contours[i]), hull[i], false );
  }



/// centre de gravité

vector<Moments> mu(contours.size() );
  for( int i = 0; i < contours.size(); i++ ){

      mu[i] = moments( contours[i], false );
  }

vector<Point2f> mc( contours.size() );
  for( int i = 0; i < contours.size(); i++ ){
    mc[i] = Point2f( mu[i].m10/mu[i].m00 , mu[i].m01/mu[i].m00 );

  }
 /// Translation*          the program bug here !!
 for(i=0; i < contours.size(); i++)
 { contours_poly[1][i].x -= mc[1].x;
   contours_poly[1][i].y -= mc[1].y;
  } 

 /// draw the new contour
 for(unsigned int i=0;i<contours.size();i++)
  {

  drawContours( drawing, contours_poly, i, colors, 1, 8, vector<Vec4i>(), 0, Point() );
  }

But I do not know if the bug is generated by the modification of a large number of points or the formula is false because here is the result: the application has requested the Runtime to terminate it in an unusual way.

Thanks.

Answer 1

Shouldn't you change the bound of your for loop?

for(i=0; i < contours[0].size(); i++)
{ 
    contours_poly[0][i].x = contours_poly[0][i].x - mc[1].x;
    contours_poly[0][i].y = contours_poly[0][i].y - mc[1].y;
    contours_poly[1][i].x = contours_poly[1][i].x - mc[1].x;
    contours_poly[1][i].y = contours_poly[1][i].y - mc[1].y; 
}