Head tracking

Introduction

Head tracking is an important way to measure responses of subject to stimuli. The head movement is measured can be measured in several ways, each with their pro's and con's. In our labs three techniques are used for head tracking: EMF, IMU and optical head tracking.

EMF head tracking

The Electromagnetic Field head tracking system consists of three low frequency (~60 kHz) magnetic field generators that create homogeneous alternating magnetic fields around the subject. There are three perpendicular fields (horizontal, vertical and frontal) each with a different frequency.

The subject is wearing a pickup coil on his/her head during the trial. This coil pick up the magnetic fields and the strength of the different frequency components is depending on the orientation of the head. The pickup coil signal is again split in three components by three lock-in amplifiers (LIA's). The outputs of the LIA's are converted by ADC's and analysed further in matlab by a pre-trained neural network.

This system is available in:

• Auditory Motion Lab (aka Robot Arm)
• Auditory Perception Lab (aka Patient Lab)
• Auditory Sphere Lab