Full-Body Tracking Using a Sensor Array System and Laser-Based Sweeps

The increased availability of consumer-grade virtual reality (VR) head-mounted displays (HMD) has created significant demand for affordable and reliable 3D input devices that can be used to control 3D user interfaces. Accurate positioning of a user's body within the virtual environment is essential in order to provide users with convincing and interactive VR experiences. Existing full-body motion tracking systems from academia and industry have suffered from problems of occlusion and accumulated sensor error while often lacking absolute positional tracking. This paper describes a wireless Sensor Array System that uses multiple inertial measurement units (IMUs) for calculating the complete pose of a user's body. The system corrects gyroscope errors by using magnetic sensor data. The Sensor Array System is augmented by a positional tracking system that consists of a rotary-laser base station and a photodiode-based tracked object worn on the user's torso. The base station emits horizontal and vertical laser lines that sweep across the environment in sequence. With the known configuration of the photodiode constellation, the position and orientation of the tracked object can be determined with high accuracy, low latency, and low computational overhead. As will be shown, the sensor fusion algorithms used result with a full-body tracking system that can be applied to a wide variety of 3D applications and interfaces.