A simple and rapid method for electromagnetic field distortion correction when using two Fastrak sensors for...

Area of Science:

• Biomechanics
• Biomedical Engineering
• Sensor Technology

Background:

• Electromagnetic motion tracking systems, like Fastrak, are susceptible to field distortions.
• These distortions introduce significant errors in position and orientation data.
• Accurate motion capture is crucial for biomechanical research and clinical applications.

Purpose of the Study:

• To develop and validate a simple, rapid method for correcting electromagnetic distortions.
• To enhance the accuracy of Fastrak sensor measurements for human motion analysis.

Main Methods:

• A novel correction method based on minimizing objective functions with derivative polynomial functions.
• Utilized 35 deformation coefficients to estimate and correct electromagnetic field distortions.
• Calibrated a 1m³ volume in approximately 3 minutes.

Main Results:

• Achieved significant error reduction in orientation: 56% (flexion/extension), 78% (ab/adduction), 56% (rotational).
• Demonstrated substantial error reduction in position: 53% (medial/lateral), 21% (anterior/posterior), 48% (proximal/distal).
• Corrected measurements showed favorable comparison with undistorted optoelectronic data (Vicon).

Conclusions:

• The proposed method effectively corrects electromagnetic distortions in Fastrak sensor data.
• This technique offers a practical solution for improving the accuracy of electromagnetic motion capture.
• The results suggest this method is a valuable tool for biomechanical and clinical studies.