When working with sub-pixel coordinates in OpenCV (e.g. chessboard corners in the camera calibration pipeline), what is the origin of this coordinate system?
I've seen this asked a few times, but the answers are always a bit ambiguous, so just to clarify:
I understand that in the integer pixel coordinate system, the origin is (0,0) at the top-left pixel. But for the coordinate system attached to floating-point sub-pixel coordinates, does (0,0) sit in the middle of the top-left pixel, or the top-left corner of the top-left pixel?
Many thanks!