Hi crackwitz,
Thank you very much for your answer!
I have a few more confusions: It seems that when I do canny, some edges are not closed, so that cannot be retrieved by using cv2.findcontour if I understand it correctly, and another issue is that some objects are very close to each other, so no matter I use threshold or canny their contours or area are then connected to each other and become one big bounding box, in the end, I’d like to have all different rotation bounding box for every object here.
Again, I really appreciate your great help!