AquaCAVE: an underwater immersive projection system for enhancing the swimming experience

AquaCAVE is an underwater immersive projection environment which faithfully reproduces the swimming experience in the virtual space. AquaCAVE is inspired by the surrounding projection system known as the CAVE Automatic Virtual Environment, where the stereoscopic images are projected to the surfaces surrounding the user, but addresses several water-specific problems that were not studied in previous systems. In this paper, we describe techniques to overcome the water-specific issues for configuring the immersive projection system. Three characteristics of water that mainly cause problems are pincushion distortion, reflection, and infrared (IR) radiation absorption. Existing motion capture systems based on IR or blue lights are not feasible for an underwater immersive projection environment since IR are absorbed, and blue lights disturb a user to see the stereo-scopic images. Therefore, we propose a setup for visible-light head tracking, which is functional for AquaCAVE. As a result, the proposed circular polarization-based method was shown to be valid to enable a constantly clear view, stable head tracking, and reflection reduction. With this methodology, we can build the proposed AquaCAVE that can be applicable to future underwater entertainment and enhanced swimming training.