AprilTag

Description

AprilTags conceptually similar to QR codes, in that they encode data as two-dimensional grid of black and white squares. However, they differ in that the AprilTags not only carry data payload, but could be used for detecting tag position and orientation.

 
Implementaton

AI Accelerator software by default configured to use the 36h11 tag family in 30 mm size. Printable tags for the 36h11 family can be found at https://docs.cbteeple.com/robot/april-tags

 

Tag size can be configured in ros/launch/ark_pipeline_full.py

  • Look for Apriltags node definition.

  • Change size argument, default value is 'size': '0.03’. Size is specified in meters.
Demo

Tag recognition could be tested by opening the ark_example_tags.

Switch to tags view in Dashboard URCap and observe the camera view updating at intervals.

Tags can be configured for continuous detection by passing apriltags_continuous:=true as an argument to ark_pipeline_full in ros/scripts/run_ark.sh
   
  The code for generating new families and instructions for using it can be found on github: https://github.com/AprilRobotics/apriltag-generation