[Python知识库]OpenCV中minAreaRect的使用说明

OpenCV中使用vector<Point>可以组成多个点的形状，或者四个点的旋转矩形。

带角度的矩形可以通过这种方式拿到：

vector<Point> ployPoints{Point(x1,y1),Point(x2,y2),Point(x3,y3),Point(x4,y5)};
RotatedRect rotated_rect = minAreaRect(ployPoints);

python中是这样的，其中segmentation是这样的：[x1, y1, x2, y2, x3, y3, x4, y4]:

segmentation = segmentation.reshape([-1, 2])
  rect1 = cv2.minAreaRect(segmentation)
  x, y, w, h, theta = rect1[0][0], rect1[0][1], rect1[1][0], rect1[1][1], rect1[2]

发一下OpenCV-C++源码对RotatedRect的表述：

class CV_EXPORTS RotatedRect
{
public:
    //! various constructors
    RotatedRect();
    RotatedRect(const Point2f& center, const Size2f& size, float angle);
    RotatedRect(const CvBox2D& box);

    //! returns 4 vertices of the rectangle
    void points(Point2f pts[]) const;
    //! returns the minimal up-right rectangle containing the rotated rectangle
    Rect boundingRect() const;
    //! conversion to the old-style CvBox2D structure
    operator CvBox2D() const;

    Point2f center; //< the rectangle mass center
    Size2f size;    //< width and height of the rectangle
    float angle;    //< the rotation angle. When the angle is 0, 90, 180, 270 etc., the rectangle becomes an up-right rectangle.
};