Motivation
- For the past 2 years ArUco tags are available on elements
- For the past 4 years ArUco tags are part of the game
- In the past ArUco were mainly justified for elements with unknown position
- This year all elements are in unknown position (or depending on updates, at least several of them)
- Elements (plants) are known to fall easily, making it even more dificult to locate and manipulate
- While other vision technics might help, ArUco tags offer a very precise position/orientation helpful for teams. This means tags are mailnly useful for close-up manipulations, rather than far-away detections.
- Teams have developped ArUco detectors, already used for robots hats, solar panels and table. So forcing the development of another vision technic might not be desirable.
Evaluation
As plants are curved, it could seem unpossible to find a flat surface for the ArUco tags, and indeed, a curve is not flat.. Hovever, due to machine vision constraints and imprecisions, detectors are already used to handle small deformations. They are base on edge and corner detection, and use averages in zones to define if it's white or black.
Size
The size of the tags just has to be adapted to the shape to minimize deformation while remaining usable. After a few tests, 13.5mm tags (the black area) gave the best results. They are less impacted by deformations, and remain very visible for manipulation purposes.
Tags
To select the tag itself, more tests shown that "simple" tags (like n°17) gives best results.
Shape
Applying a tag arround a curve object deforms its dimensions, but we can counter it with some inkscape magic.
Result
