Checkerboard Extrinsic Calibration 

1. Preparing the Checkerboard

The accuracy of extrinsic calibration depends heavily on the physical quality of the checkerboard. Rigidity, correct scale, and surface finish are critical.

Board Requirements

• Image: A1.zip

• Material: Print the provided checkerboard pattern with matt-over-laminate on an A1 aluminium honeycomb or aluminium composite board.

  • The board must remain perfectly flat. Any bending or warping will reduce calibration accuracy.

• Printing: Print at 100% scale (do not use scale to fit).

• Finish: Use a matte finish to prevent glare.

2. Locking the Camera Setup

Before recording the calibration:

• All cameras must be fully installed and locked in their final positions.
• Ensure lenses are focused and exposure is stable.
• The cameras should be at approximately a 45 degree angle when looking at the centre of the volume, to ensure the checkerboard can be detected well when placed on the floor
• Do not move or re-angle any camera/lens after extrinsic calibration.

3. Setting the World Origin

The position of the checkerboard during first few seconds of the calibration recording define the world coordinate system (0,0,0).

Initial Placement

• Place the checkerboard flat on the floor at the desired centre of the capture volume.
• This position defines:
  • Ground Plane: Z = 0
  • World Origin: The board’s reference coordinates

Axis Alignment

• The orientation of the checkerboard defines the X and Y axes of the world.
• If your floor has axis markings, align the arrows or edges of the board to match them.

Clear Initialisation

• Keep the capture volume completely empty for the first 2–3 seconds of recording.
• No people, equipment, or occlusions should be present.

4. Recording the Calibration Video

Step-by-Step Movement Pattern (Recommended)

Follow this sequence carefully for best results:

• Pick up the checkerboard from the centre of the volume, keeping it rigid and fully visible.
• Face the first camera and:
  • Walk from the centre directly towards the camera keeping the board facing the camera at all times.
  • When you reach the limit of the volume, walk backwards to the centre, still facing the same camera and keeping the board visible.

• Repeat step 2 for each camera in the setup.
  • Always start and end at the centre of the volume.
• After all cameras are covered individually:
  • Walk the entire perimeter of the capture area with the checkerboard facing inward toward the centre of the volume at all times.

This motion pattern ensures:

• Robust triangulation across the full volume
• A well-defined virtual perimeter

5. Processing the Calibration in Move Pro

Creating the Calibration Take

1. Create a new calibration take with your videos.
2. Select Checkerboard as the calibration method.
3. Start processing the take.

Output validation

After processing, view the active capture area, world origin and camera transformations (positions and orientations) overlays in the viewport to verify the accuracy of the calibration

Check that:

• The origin is correctly placed at the centre of the volume
• The ground plane aligns with the physical floor
• Camera positions are consistent with the real-world setup

6. When to Recalibrate

Re-run checkerboard extrinsic calibration if:

• Any camera is moved or re-angled
• The capture volume size or layout changes
• The world origin or axis alignment needs adjustment

Here is an example

• Sync Type: Checkerboard
• Sync method: Sync