Effects of calibration errors on 3D kinematics quantification with fluoroscopy

Model based 3D fluoroscopy can quantify joint kinematics with a mm/deg accuracy level. A calibration based on the acquisition of specific devices is usually applied to size the system. This study aimed at the characterization of the sensitivity of the pose estimation accuracy to errors in the calibration process, in order to evaluate a possible simplification of the calibration procedure. In-silico simulations were performed to analyse a data-set obtained adding controlled perturbation in the calibration process. The estimation of the rotations was scarcely influenced by calibration errors, while a linear trend was high- lighted for translations with a sensitivity of 20% correspondent to approximately a 1 mm error for realistic calibration errors. This error is compensated when computing relative kinematics between two joint segments.