PuzzleBoard: A Checkerboard Target with Lightweight Position Encoding

Welcome to the PuzzleBoard Website

Here you will find everything you need for working with the PuzzleBoard, including demo videos, the scientific papers, a pdf board generator for generating custom puzzle boards and some demo code for decoding PuzzleBoard images.

Introduction

The often used checkerboard calibration pattern (based on Zhang et al.'s seminal work) lacks any positional encoding. Thus, the calibration pattern must be completely visible without any occlusions. In some applications alternative solutions are preferred. E.g. ArUco or ChArUco boards allow partial occlusions, but require a higher camera resolution to read the code.

The PuzzleBoard is a new alternative that combines the advantages of checkerboard calibration patterns with a lightweight position coding that can be decoded at very low resolutions. Even very small image sections are unique in terms of translation and rotation. The decoding algorithm includes error correction and is computationally efficient.

PuzzleBoards can be used not only for camera calibration but also for camera pose estimation and marker-based object localization tasks (the markers will then be small subpatterns of the PuzzleBoard pattern).

The code is based on a mathematical concept called De Bruijn Torus.

Demo Videos

Here are some short demo videos (for download and as youtube link) showing the capabilities of the PuzzleBoard:

Papers

Different aspects of the PuzzleBoard have been introduced in the following papers:

Stelldinger, P., Schönherr, N., Biermann, J.: PuzzleBoard: A New Camera Calibration Pattern with Position Encoding, In: Proceedings of the 46th German Conference on Pattern Recognition (GCPR) 2024.
This paper introduces the PuzzleBoard.
Stelldinger, P.: On de Bruijn Rings and Families of Almost Perfect Maps, arXiv 2024.
The math behind the position code.

If you use the PuzzleBoard in your research, please cite the GCPR 2024 paper. If you have written a paper using the PuzzleBoard, please send me a mail and I will add you paper in this list.

PuzzleBoard Patterns

Here are some examples of PuzzleBoard patterns for download as pdf:

Board Generator

You can generate a pdf of any part of the PuzzleBoard pattern by just choosing its size and starting position. Before downloading, you need to click at the "generate pattern" button.

Although it is not recommended, you can change the bit code for both the horizontal and the vertical edges. Do this only if you know what you are doing, as changes most probably result in non-unique position codes.

start x	start y
width	height
paper width [mm]	paper height [mm]
edge length [mm]	calculate paper size
00001011100001110101010100100011010110110000111011100010100100010001111110000010101111110100110010010101110101110000111111011011010110011011111011100111101001111010001 01100001111110111111110100010010000011110001001100000100010001100001100000011100011010100011101110101101110110010010000110100110001110101000111000100110001111010100100 01000001010000111010000111101011111010000010010010000101110100110110011101011010110010110010010010110011001011110111001110000000101011011111010110110011000011110100011 11111010100111111000010100110111100100000100110010011111100011010001110110100100001000111001111010000000100111000000010111110010110101111101110100101101011001001110010 10110011000100110101100111011000011010100010010101011000001011000000111000001011011000011111010101101101100011001111001001001010111011011001110011001011100011100011001 00110000010101000111101010010110000110010010000000110000111101000111101100101010100100101001011111101000000010110101101011111110001000111101011101100101000011011111111

Code

GitHub (Python version)

Contact

If you have a question regarding the PuzzleBoard, please send me a message:

E-Mail: peer.stelldinger@haw-hamburg.de