Because I’m not just tracking the rotation of a rectangle along the axis of the rectangle to the camera (z axis), but I need the translation vector and rotation matrix from the camera to this plane. Blob tracking does not provide me enough information for this. Even if I were to use it for detecting the corners of the rectangle, the min_corners sometimes does not detect the corners properly (as mentioned in the post). I would upload an image to show what I mean, but apparently new users are not allowed to upload images.