# Revision history [back]

### how to find the REAL width and height of contours

there is a image of 3 shapes

if i use the code blew ,i get the result

int main( int argc, char** argv )
{
Mat bw;
bool dRet;
//resize
pyrDown(img,img);
pyrDown(img,img);

cvtColor(img, bw, COLOR_BGR2GRAY);
//morphology operation
threshold(bw, bw, 150, 255, CV_THRESH_BINARY);
//bitwise_not(bw,bw);
//find and draw contours
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
findContours(bw, contours, hierarchy, CV_RETR_LIST, CV_CHAIN_APPROX_NONE);
for (int i = 0;i<contours.size();i++)
{
RotatedRect minRect = minAreaRect( Mat(contours[i]) );
Point2f rect_points[4];
minRect.points( rect_points );
for( int j = 0; j < 4; j++ )
line( img, rect_points[j], rect_points[(j+1)%4],Scalar(255,255,0),2);
}
imshow("img",img);
waitKey();
return 0;
}


but ,in fact ,the contour 1 and contour 2 which i fingure out in RED do not get the right widht and height.

what i want should be this

i did't find the appropriate function or any Doc from Opencv to do this work It's been bothering me for days any help will be appreciate!