Tag bundle calibration

[jack-slip]

Summary of Solution

Created a node called apriltag_ros_tag_bundle_calibration_node that consumes a remap-able ~tag_detections feed until it reaches max_detections. You can set the master tag with param master_tag_id. It then averages the observed transforms to the master tag id over the duration of the observations and writes the generated config file to config_file_path. We average the transforms' quats using tf2::Quaternion::slerp() which seems to perform adequately.

Open questions

• License headers on new files
• Unable to test against matlab script as ground truth (namely to compare slerp() to the home-brewed quat averaging solution)

Successive Work

• I would like to modify the code to allow transform chaining, so that the master tag id doesn't always have to be in frame

Demo

In the attached demo, we run a tag detector on a 3 x 3 tag grid with tag sizes 3cm and spacing between tags 4.5cm center to center along x and y. Camera is running at 15hz 720p rectified. 500 max detections. Would likely get better results at a higher resolution and higher max detections. This demo had largest errors on the z axis (max error was 7mm for tag 8) Whereas x and y errors were all sub mm. I will likely do some more testing with more detections and higher resolution (and flatter targets i.e not tags taped to the wall).

tag_bundle_calib_rosnode_demo-2023-04-21_09.51.16.mp4