Less image delays, less 'image echoes' and more fluid movements in virtual reality (VR): this is all possible with the research of Ferdi Smit of the Centrum Wiskunde & Informatica (CWI), the Dutch national research center for mathematics and computer science in Amsterdam, the Netherlands. On November 12 Smit received his PhD degree at the Eindhoven University of Technology for his dissertation 'A Programmable Display-Layer Architecture for Virtual Reality Applications'. His results will be of interest to researchers, game designers and the medical world.
The quality of VR pictures is not yet optimal. For instance, often a delay occurs between the movement of a trackball, mouse or head and the movement on the screen. "Though it is often no more than 50 or 100 milliseconds, you can still become dizzy or sick from this delay, especially in a VR environment with a helmet on", the researcher says. This phenomenon is called 'latency'. Another problem is 'cross-talk': the 'echo' of an image when using 3D glasses in combination with a stereoscopic display. Smit: "On these particular displays the left and right images quickly alternate. This makes you see some sort of shadow next to the 3D image”. Finally, there is 'judder': the phenomenon that a moving object on a screen seems to move in steps rather than moving smoothly. Ferdi Smit combined and improved different techniques to detect and reduce these unpleasant results in VR. He added an additional software layer, the 'programmable display layer' (PDL), in order to update the display quickly and independently.
New in Smit's approach is that his method dynamically detects errors, and solves them in real-time. One of the methods the researcher used to generate images faster with PDL is 'image warping'. A VR image often looks quite similar to the previous one. Until now, images are usually calculated one at a time. However, image warping takes the previous image, slightly modifies it and then adjusts it for differences with the real situation. This saves time. The researcher implemented his method in real-time on 60 Hz displays. This proved to work well. Results can be used in visualization of large models, such as CT-scans of medical data.
- the thesis
- the homepage of supervisor Robert van Liere, and www.cwi.nl/ins3.
- The research was funded by the NWO research programme VIEW (Visual Interactive Effective Worlds) from the i-science cluster program of NWO Physical Sciences.