//!computes the minimal rotated rectangle for a set of points
RotatedRect minAreaRect(InputArray points);//計算一些列點的最小外接矩形，帶角度資訊

C++: RotatedRect minAreaRect(InputArray points)
Python: cv2.minAreaRect(points) → retval
C: CvBox2D cvMinAreaRect2(const CvArr* points, CvMemStorage* storage=NULL )
Python: cv.MinAreaRect2(points, storage=None) → Box2D

Parameters:points-

Input vector of 2D points ,stored in:
1: std::vector<>or Mat (c++ interface)
2:CvSeq * or CvMat *(C interface)
3:Nx2 numpy array(python interface)

測試案例：

    vector<Vec4i> hierarchy;
    vector<vector<Point>> contours;
    findContours(src, contours, hierarchy, RETR_LIST, CHAIN_APPROX_SIMPLE, Point(0
 
, 0));
    vector<vector<Point>>::iterator iter = contours.begin();
    RotatedRect resultRect;
    while (iter != contours.end())       
    {
        resultRect = minAreaRect(*iter);//獲取輪廓的最小外接矩形       
            Point2f pt[4];
            resultRect.points(pt);//獲取最小外接矩形的四個頂點座標
            //繪製最小外接矩形
 

            line(src, pt[0], pt[1], Scalar(255, 0, 0), 2, 8);
            line(src, pt[1], pt[2], Scalar(255, 0, 0), 2, 8);
            line(src, pt[2], pt[3], Scalar(255, 0, 0), 2, 8);
            line(src, pt[3], pt[0], Scalar(255, 0, 0), 2, 8);
            cout << "*******************************" << endl;
            cout << "X座標" << resultRect.center.x << "Y座標" << resultRect.center.y << "偏移角度"<<resultRect.angle<<endl;
            cout << "*******************************" << endl;
        }