Comparative Measurement of the Head Orientation Using Camera System and Gyroscope System

The aim of article is to compare two fundamentally different MoCap systems used to measure head orientation. We used IR medical camera and one 3DOF orientation tracker placed on subject’s head and measured 3-D data - inclination (roll), flexion (pitch) and rotation (yaw). The volumes of 3D confidence ellipsoids were used to compare the two systems. Using the volumes of confidence ellipsoids, we were able to model the distribution of the measured 3-D data. Ten healthy subjects in the study were measured and statistical analysis was performed. The results of the comparative method based on the confidence ellipsoid show that the volumes related to the 3DOF orientation tracker are significantly larger than the volumes related to the IR medical camera. Although the results are different when using different MoCap systems, the MoCap systems identified the same subject’s behavior and deterioration or improvement of stability. The comparative measurement based on concept of confidence ellipsoid volume has not been used before to study the MoCap systems used to measure head orientation. The methods can be used to compare other types of MoCap systems and can also be used to study other segments of human body.