Detect the chessboard


python3 apps/calibration/ ${root}/ba --mode sparse --squareLength 0.1 --aruco_len 0.0714
python3 apps/annotation/ ${root}/ba --annot chessboard --mode chessboard --pattern 5,3
–squareLength the length of the square (unit meter)


python3 apps/calibration/ ${root}/background1f --N 4 --N_group 4
python3 apps/annotation/ ${root}/background1f


1. Basketball Court

Download the Web Annotation Tool.

git clone

Start the server, open the server in the browser:

python3 --root ${data}/ground1f --port 2345

Annotate the points and export.

You should measure the length of (0, 1) and (0, 3). It’s 5.8meter and 4.9meter ideally.


Image 000000.jpg has its annotation file 0000000.json:

    'keypoints3d': [[x0, y0, z0], [x1, y1, z1], ..., ],
    'keypoints2d': [[u0, v0, c0], [u1, v1, c1], ..., ].