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The object or the image has the same size and for the detection, i used findcontours() and ApproxpolyDP to find the contours points and i got the gravity center

Hello, i'm searching a function in Opencv which returns the angle of a specific object on image from its contour points or points of its related envelope. Exemple: !

Thanks guys, i resolved my problem

Hi,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

I did the translation of contour points (about 300-1000 poitns) ie each point I changed its X and Y coordinates to move the vector XOY center of gravity with this formula: for(i=1;i<contours.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; } // mc[1].x and mc[1].y are the coordinate of center of gravity

But I do not know if the bug is generated by the modification of a large number of points or what is the formula that is false. thank you

Hello,

What does it mean that you display this message "the application has requested the runtime to terminate it in an unusual way" after inserting a correct program in Qt creator C + +. Thanks

EDIT 1:

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

for(i=1;i<contours.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; 
} // mc[1].x and mc[1].y are the coordinate of center of gravity

But I do not know if the bug is generated by the modification of a large number of points or what is the formula that is false. thank you

Thanks a lot :D

I can't extract the coordinates of a specific point(the X and the Y) of my vector "contours_poly"

Hello,

I want to extract a specific point in vector

vector <vector <Point>> contours_poly (contours.size ());

but I could not extract its coordinates (X and Y) because I used matrices. Here is my code:

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

Merci.

Ok, I mean surface area of the contour

Thanks but i want calculate the surface inside the contour. I used findcontour and convexhull with a matrices.

Hello, I am trying to create a project that extract parts of an image, knowing that I have determined the contour points and I determined points related envelope and now I want to calculate the surface of the parties are between the edge points and the points of the envelope.

Here is an example:

I found on the net a function that retrieves rectangles cvSetImageROI but the problem parts that I want to extract have different shapes. In short, help me!

Hi, I am trying to complete a project in C + + using the OpenCV library and I have a problem with the display of coordinates of points that are stored in a table "pt" knowing that the table is not empty, here or a piece of code is the error:

CvPoint *pt[result->total];

        for(int i=0;i<result->total;i++){
            pt[i] = (CvPoint*)cvGetSeqElem(result, i);
            cvDrawCircle( img, *pt[i] , 4, cvScalarAll(200) );
           CvPoint x;
                    x=cvPoint(i,i);
        printf("%d \n",pt[i]);
        }

## Thanks :)