Calibration is crucial for a motion capture system to ensure accurate tracking and data quality by aligning the system to the physical environment and subjects. 

How is calibration done in each modality? 

Use a calibration object to calibrate both passive and active optical cameras. Move the object through each camera’s field of view to ensure the full measurement volume is captured, allowing the system to map the cameras’ positions relative to one another.

Intrinsic camera parameters such as lens optics, digital sensors and operating electronics all have optimum running temperatures that can be affected by temperature changes, affecting calibration accuracy. This may be due to outdoor weather, air conditioning or heating. Optimizing these during each calibration ensures better data captures.

Markerless motion capture systems require video camera calibration. Some can use the same method as optical systems, some require geometrical calibration (checker board).

IMUs can be calibrated to a global axis to  match each other or another system, such as  an optical one.