I have a chessboard and I want to calibrate my camera attached to a telecentric lens using it. But I can't get the corner points at sub-pixel accuracy with OpenCV's cv.cornerSubPix() command. When I run it, it gives no results. Then when I crop the image and enter the appropriate square number, I get the same result, nothing changes! It gives me an empty list of corner pixels. Can you help me?
You can access original images here: https://drive.google.com/drive/folders/1XmjOvUFBop7Fxzrjo-_7MawiDI-b0GxF?usp=share_link
