Capture Volume: Extrinsic Calibration¶
Processing steps¶
- Save videos to
project_root/calibration/extrinsic/
according to the naming convention outlined in Project Setup - Ensure that videos were synchronized when recording, or provide a
frame_time_history.csv
file so that caliscope can perform the synchronization during processing. - You may need to reload the workspace for the
Calibrate Capture Volume
button to become enabled - Pressing
Calibrate Capture Volume
will initiate the calibration. The final log statement at complete will indicate thatpoint_esimates.toml
has been saved. at this point you can reload the workspace and theCapture Volume
tab will become enabled. - On the
Capture Volume
tab you can visually inspect the relative position of the cameras according to the calibration - Set the board origin to a given frame to align the world frame of reference with the board position. This can be refined by flipping the axes.
Practical Recording Guidelines¶
-
Ensure Coverage and Overlap:
- Cover the entire volume where the cameras' fields of view overlap with the Charuco board movements.
- Ensure there's sufficient overlap in the fields of view of the different cameras. This overlap is critical for multi-camera calibration.
-
Use a board with sufficiently large squares
- Larger ArUco markers can be identified from farther away allowing a larger capture volume to be calibrated.
-
Minimize motion blur
- motion blur can substantially compromise corner recognition
- using a higher frame rate can reduce motion blur
- this will require more light to maintain good illumination
-
Consistent Focus:
- Use manual focus if available to keep the focus consistent throughout the filming.
- Auto-focus can introduce inconsistencies
-
Use the board to define the origin
- this is for convenience and not a strict requirement
- touch the board to the ground while it is held vertically
- ensure that the top left corner of the board (as shown on the
Charuco
tab) is in view of the camera and touching the ground