Display systems typically operate at a minimum rate of 60 Hz. However, existing VR-architectures generally produce application updates at a lower rate. Consequently, the display is not updated by the application every display frame. This causes a number of undesirable perceptual artifacts. We describe an architecture that provides a programmable display layer (PDL) in order to generate updated display frames. This replaces the default display behavior of repeating application frames until an update is available. We will show three benefits of the architecture typical to VR. First, smooth motion is provided by generating intermediate display frames by per-pixel depth-image warping using 3D motion fields. Smooth motion eliminates various perceptual artifacts due to judder. Second, we implement fine-grained latency reduction at the display frame level using a synchronized prediction of simulation objects and the viewpoint. This improves the average quality and consistency of latency reduction. Third, a crosstalk reduction algorithm for consecutive display frames is implemented, which improves the quality of stereoscopic images. To evaluate the architecture, we compare image quality and latency to that of a classic level-of-detail approach.

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. 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.

We describe an architecture that provides a programmable display layer in order to allow the execution of custom programs on consecutive display frames. This replaces the default display behavior of repeating application frames until an update is available. The architecture is implemented using a multi-GPU system. We will show three applications of the architecture typical to VR. First, smooth motion is provided by generating intermediate display frames by per-pixel depth-image warping using 3D motion fields. Smooth motion can be beneficial for walk-throughs of large scenes. Second, we implement fine-grained latency reduction at the display frame level using a synchronized prediction of simulation objects and the viewpoint. This improves the average quality and consistency of latency reduction. Third, a crosstalk reduction algorithm for consecutive display frames is implemented, which improves the quality of stereoscopic images.

Stereo displays suffer from crosstalk, an effect that reduces or even inhibits the viewer's ability to correctly perceive depth. Previous work on software crosstalk reduction focussed on the preprocessing of static scenes which are viewed from a fixed viewpoint. However, in virtual environments scenes are dynamic, and are viewed from various viewpoints in real-time on large display areas. In this paper, three methods are introduced for reducing crosstalk in virtual environments. A non-uniform crosstalk model is described, which can be used to accurately reduce crosstalk on large display areas. In addition, a novel temporal algorithm is used to address the problems that occur when reducing crosstalk in dynamic scenes. This way, high-frequency jitter caused by the erroneous assumption of static scenes can be eliminated. Finally, a perception based metric is developed that allows us to quantify crosstalk. We provide a detailed description of the methods, discuss their tradeoffs, and compare their performance with existing crosstalk reduction methods

We introduce an architecture for smooth motion in virtual environments. The system performs forward depth image warping to produce images at video refresh rates. In addition to color and depth, our 3D warping approach records per-pixel motion information during rendering of the three-dimensional scene. These enhanced depth images are used to perform per-pixel advection, which considers object motion and view changes. Our dual graphics card architecture is able to render the 3D scene at the highest possible frame rate on one graphics card, while doing the depth image warping on a second graphics engine at video refresh rate.