A shared-scene-graph image-warping architecture for VR: Low latency versus image quality

Designing low end-to-end latency system architectures for virtual reality is still an open and challenging problem. We describe the design, implementation and evaluation of a client–server depth-image warping architecture that updates and displays the scene graph at the refresh rate of the display. Our approach works for scenes consisting of dynamic and interactive objects. The end-to-end latency is minimized as well as smooth object motion generated. However, this comes at the expense of image quality inherent to warping techniques. To improve image quality, we present a novel way of detecting and resolving occlusion errors due to warping. Furthermore, we investigate the use of asynchronous data transfers to increase the architecture's performance in a multi-GPU setting. Besides polygonal rendering, we also apply image-warping techniques to iso-surface rendering. Finally, we evaluate the architecture and its design trade-offs by comparing latency and image quality to a conventional rendering system. Our experience with the system confirms that the approach facilitates common interaction tasks such as navigation and object manipulation.