CODEWITHSUNDEEP
pythonopencvcontour
RC0993
RC0993

Reputation: 958

What is the output of minAreaRect(contours)

I have recently started working with openCV and and python. I have a project where I am finding contours using findContours. I get roughly around 6-8 contours on which I am looping to get the bounding box that fits the contour.

For that I have used minAreaRect(contours) which gives me rotated rectangle that should fit the contour. Now the output of this command is a list of tuples.

Each tuple looks like this ((81.0, 288.0), (22.0, 10.0), -0.0) I couldnt get any description on what each of that number mean?

I think it might be ((x-coordinate, y-coordinate),(width, height), rotation).

Upvotes: 5

Views: 18296

Answers (2)

Serghei
Serghei

Reputation: 41

Based on my observations that function gives u back following: (center(x, y), (width, height), angle of rotation) = cv2.minAreaRect(points)

Upvotes: 0

HansHirse
HansHirse

Reputation: 18895

You are correct. Having a look at OpenCV's (C++) documentation on cv::minAreaRect, we see that a cv::RotatedRect is returned. The full construcor of cv::RotatedRect is:

cv::RotatedRect::RotatedRect(const cv::Point2f& center, const cv::Size2f& size, float angle)

The description of the corresponding parameters is:

center    The rectangle mass center.
size      Width and height of the rectangle.
angle     The rotation angle in a clockwise direction. When the angle is 0, 90, 180, 270 etc., the rectangle becomes an up-right rectangle.

Obviously, center and size are treated as tuples in the Python API, and all three parameters are returned as a tuple also. So, all in all this fits quite well your assumption.

Hope that helps!

Upvotes: 9

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