WhyCon Markers, AruCo Markers

 

Do you have a web camera?  And need a high-performance localising system? Then you probably have to look into whyCon Markers

WhyCon Marker:

It is a vision-based localization system that can be used with low-cost web cameras, and achieves millimetre precision with very high performance. The system is capable of efficient real-time detection and precise position estimation of several circular markers in a video stream. WhyCon is meant as an alternative to widely used and expensive localization systems. It is fully open-source. WhyCon-orig is WhyCon's original, minimalistic version that was supposed to be ROS and openCV independent.

Working:

The base of the localization system is an efficient circular target detector. This efficiency allows for the detection of hundreds of targets above camera frame-rate. The targets can be easily printed on a B&W printer. A single target allows for obtaining 5DoF (3D position + 2 angles). When constrained on planar (ground) motions, the precision can be further improved

ArduCo Basic

AruCo Markers:

AruCo Markers are, as similar to QR codes which have a unique identity. AruCo marker consists of 7 by 7 binary grids. But the pattern is considered only inside 5 by 5 grids. Black represents 0, and white represents 1. In Aruco Markers 1^st,3^rd and 5^th column represents parity bits and 2^nd and 4^th column represents dt bits as shown in figure yellow represents parity bits and light blue represents a data bit.

So maximum number marker can be encoded is 

A sample of AruCO

                            2^`10 =1024

Figure 1 AruCo Sample

So, we can create 1024 unique IDs

 

 

 

 References

1.       A Practical Multirobot Localization System” , T. Krajník, M. Nitsche, J. Faigl, P. Vaněk, M. Saska, L. Přeučil, T. Duckett, and M. Mejail, ,” Journal of Intelligent & Robotic Systems, 2014.

2.       External localization system for mobile robotics” , T. Krajnik, M. Nitsche, J. Faigl, T. Duckett, M. Mejail, and L. Preucil, ,” in Advanced Robotics (ICAR), 2013 16th International Conference on, 2013

3.       https://www.youtube.com/watch?v=6OH-wOsVVjg