无法使用opencv minAreaRect获取对象的边界

Question

I am trying to draw a minimum bounding rectangle around an object in an image using openCV,

the cv2.minAreaRect is returning the rectangle of correct size but its orientation is off

Following is my codeSnippet

The following screentshot shows the image i am working

In the next screenshot it shows the image with the detected border

According to the opencv documentation linked here: https://docs.opencv.org/3.4/dd/d49/tutorial_py_contour_features.html this should work

Answer 1

np.where() returns things in the normal array index (row, column) order, but OpenCV expects points in (x, y) order, which is opposite to (row, column). This has the effect that you are flipping the points about the diagonal of the image.

Simply reverse the points by swapping the two columns. Better yet would just be to be more explicit with variables and not do everything on one line:

y, x = np.where(binary == 0)
coords = np.column_stack((x, y))