Wang, Chu P., Lawrence Koved, Semyon Dukach. Design for Interactive Performance in A Virtual Laboratory. Proceedings of 1990 Symposium on Interactive 3D Graphics (Snowbird, UT, 1990). In Computer Graphics, 24, 2 (March 1990) pp. 39-40.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....send to the display. Unfortunately, this ingenious trick works only for orientation, and our existing Pixel Planes 5 frame buffers are not capable of supporting this technique. It s main advantage is reducing how far into the future a prediction heuristic needs to estimate future locations. Wang [Wang90] from IBM Yorktown Heights mentions, but does not describe, a prediction system for tracking hand motion. They have had problems with overshoots caused by rapid acceleration or deceleration, and a conversation with Dan Ling indicated that they have not done much work in this area. The flight ....

Wang, Chu P., Lawrence Koved, Semyon Dukach. Design for Interactive Performance in A Virtual Laboratory. Proceedings of 1990 Symposium on Interactive 3D Graphics (Snowbird, UT, 1990). In Computer Graphics, 24, 2 (March 1990) pp. 39-40.

....was devised to reduce the noise in position data. The effectiveness and limitations of both approaches were then studied, and the results shown to be satisfactory. 1 Introduction In recent years, the virtual reality concept has been explored by many researchers [Krueger83] Fisher86] Brooks86] [Wang90] [Green90] To provide real time visualization of a 3 D space, a Polhemus Isotrak tracker is often used to determine the user s viewpoint and line of sight, and based on the measured data, stereoscopic images are generated and displayed to the user through the head mounted display. In this ....

....the measured data, stereoscopic images are generated and displayed to the user through the head mounted display. In this paradigm, two factors adversely affect the user s perception of the virtual world, namely, the jittering of images and the lag between head movement and visual feedback [Rebo89] [Wang90]. 0 The jittering of images is caused by the noise in the measured data. The lag is due partly to the computation and rendering time needed to generate the images, and partly to the delay in the measured data. To generate new tracking data, the Isotrak generates and senses electromagnetic ....

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C. P. Wang, L. Koved, and S. Dukach, "Design for interactive performance in a virtual laboratory," Proc. 1990 Symp. on Interactive 3D Graphics, Utah, March 1990, pp. 39--40.

....use a continuously varying AC current. There are various configurations possible. A single emitter and receiver can update at 60 Hz. Four emitters can be used which reduces the performance to 15 Hz per emitter. However several researchers report worse practical performance, one of only 20 Hz [WKD90, Pau91, WCF90, Wen92] The Ascension devices use a pulsed DC current. There are three systems. Bird is a single sensor unit, Big Bird is a single unit with a larger sensing volume and Flock of Birds can support up to six sensors. These units are rated at 100 Hz. The Ascension devices perform ....

C. Wang, L. Koved, and S. Dukach. Design for interactive performance in a virtual laboratory. Computer Graphics, 24(4):39--40, March 1990.

....governor keeps track of the time and helps the application to produce the smooth output. This architectural model is similar to the Decoupled Simulation Model outlined in section 3. Researchers at IBM have been using multiple workstations to support the real time requirements of VR user interfaces [Wang 1990, Lewis 1991] They have assigned a workstation to each of the devices in their user interfaces and an event based UIMS is used to coordinate the input coming from several devices. MR uses a similar device management approach, as described in section 5.2 of this paper. Holloway at UNC at Chapel ....

C. Wang, L. Koved, and S. Dukach, Design for Interactive Performance in a Virtual Laboratory, Proceedings of 1990 Symposium on Interactive 3D Graphics, Computer Graphics 24, 2 (1990), pp. 39--40.

.... is attractive to VR system designers, and thus several VR systems are network parallel or MP parallel (Appino, Lewis, Koved, Ling, Rabenhorst, Codella, 1992; Codella, Jalili, Koved, Lewis, 1993; Gobbetti, Balaguer, Thalmann, 1993; Lewis, Koved, Ling, 1991; Shaw, Liang, Green, Sun, 1992; Wang, Koved, Dukach, 1990). All these systems use asynchronous or other ad hoc process communication (except for left and right eye view rendering) Yet asynchronous communication maximizes throughput but is suboptimal for reducing lag. While Appino et al. (Appino, Lewis, Koved, Ling, Rabenhorst, Codella, 1992) mention ....

....to each computation stage. Using at least one CPU for each computation stage in a VR application, even in asynchronous communications mode (Appino, Lewis, Koved, Ling, Rabenhorst, Codella, 1992; Codella, Jalili, Koved, Lewis, 1993; Lewis, Koved, Ling, 1991; Shaw, Liang, Green, Sun, 1992; Wang, Koved, Dukach, 1990), has four main advantages. First, the user input device is independent from all other stages and thus runs with maximum throughput, allowing use of prediction (see Figure 2) Second, rendering also proceeds at maximum throughput, reducing frame rate induced lag (see Section 3) Third, the ....

Wang, C. P., Koved, L., & Dukach, S. (1990). Design for interactive performance in a virtual laboratory. Computer Graphics (1990 Symposium on Interactive 3D Graphics), 24(2), 39--40.

.... generated and displayed to the user through the Head Mounted Display (HMD) In this paradigm, two factors associated with tracking technology adversely affect the user s perception of the virtual world, namely, the jittering of images and the lag between head movement and visual feedback [Rebo89] [Wang90] [Liang91] The jittering of images is caused by the noise in the measured data, and will not be considered further. The lag is due to three system components: The first component is the time taken by the tracker system to measure and calculate the position of its sensing unit. The second ....

C. P. Wang, L. Koved, and S. Dukach, "Design for interactive performance in a virtual laboratory, " Proc. 1990 Symp. on Interactive 3D Graphics, Utah, March 1990, pp. 39--40.

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