In 1960 Rudolph E. Kalman published his now famous article describing a recursive solution to the discrete-data linear filtering problem (Kalman, “A new approach to linear filtering and prediction problems,” Transactions of the ASME—Journal of Basic Engineering, 82 (D), 35–45, 1960). Since that time, due in large part to advances in digital computing, the Kalman filter has been the subject of extensive research and applications, particularly in the area of autonomous or assisted navigation. The purpose of this paper is to acknowledge the approaching 50th anniversary of the Kalman filter with a look back at the use of the filter for human motion tracking in virtual reality (VR) and augmented reality (AR).
In recent years there has been an explosion in the use of the Kalman filter in VR/AR. In fact, at technical conferences related to VR these days, it would be unusual to see a paper on tracking that did not use some form of a Kalman filter, or draw comparisons to those that do. As such, rather than attempt a comprehensive survey of all uses of the Kalman filter to date, what follows focuses primarily on the early discovery and subsequent period of evolution of the Kalman filter in VR, along with a few examples of modern commercial systems that use the Kalman filter.
This paper begins with a very brief introduction to the Kalman filter, a brief look at the origins of VR, a little about tracking in VR—in particular the work and conditions that gave rise to the use of the filter, and then the evolution of the use of the filter in VR.