Measurement of IMU sensor quality used for head tracking in auralization systems

International audienceThe audio in Virtual Reality (VR) systems is often based on forming binaural signals for the listeners from 3D sound environments recorded or synthesized using the Ambisonics encoding system. The VR systems must have an integrated head tracking system, so that the users can experience both auditory and visual information as naturally as possible. To achieve this goal, all such systems use some sort of Inertial Measurement Unit (IMU) sensors that are built into the hardware of the headsets. The headsets range from simple headphones with added IMU sensors, through smartphones that must be fastened to headset phone holders, up to commercial stand-alone VR headsets. Consequently, the range of the IMU sensors and their quality is quite broad as well. This paper presents the quality assessment made for different IMU sensors in terms of delay, the precision of determining the right direction of the sensors, and the long-term stability concerning the parameter drift. The listed parameters were measured for sensors built into a range of Android- based smartphones. The measurements were also made on typical stand-alone IMU sensors that have to be added to an embedded system for collecting positional data, and can be mounted to headphones or other VR system. All measured units were compared and the conclusions about their quality are given