Managing level of detail through peripheral degradation

Abstract

Two user studies were performed to evaluate the effect of level-of-detail (LOD) degradation in the periphery of head-mounted displays on visual search performance. In the first study, spatial detail was degraded by reducing resolution. In the second study, detail was degraded in the color domain by using grayscale in the periphery. In each study, 10 subjects were given a complex search task that required users to indicate whether or not a target object was present among distracters. Subjects used several different displays varying in the amount of detail presented. Frame rate, object location, subject input method, and order of display use were all controlled. The primary dependent measures were search time on correctly performed trials and the percentage of all trials correctly performed. Results indicated that peripheral LOD degradation can be used to reduce color or spatial visual complexity by almost half in some search tasks without significantly reducing performance.

Gaze-Contingent Multiresolutional Displays: An Integrative Review

“…Thus, the GCMRD concept is now beginning to be validated. Furthermore, general perceptual disruptions and performance decrements have been shown to be caused by (a) peripheral degradation removing useful visual information or inserting distracting information (Geri & Zeevi, 1995;Kortum & Geisler, 1996b;Loschky, 2002;Loschky & McConkie, 2000;Parkhurst et al, 2000;Peli & Geri, 2001;Reingold & Loschky, in press;Watson et al, 1997;Yang et al, 2001) and by (b) D-AOI update delays (Frank et al, 1988;Grunwald & Kohn, 1994;Hodgson et al, 1993;Loschky & McConkie, 2000, Exp. 1 & 6;McConkie & Loschky, in press;Turner, 1984;van Diepen & Wampers, 1998).…”

“…[Insert Table 1 about here] Unfortunately, GCMRDs can also produce perceptual artifacts, such as perceptible image blur or image motion, which have the potential to distract the user (Loschky, 2002;Loschky & McConkie, 2000;McConkie & Loschky, in press;Parkhurst, Culurciello, & Neibur, 2000;Reingold & Loschky, in press;van Diepen & Wampers, 1998;Watson, Walker, Hodges, & Worden, 1997). Ideally, one would like a GCMRD that maximizes the benefits of processing and bandwidth savings while minimizing perception and performance costs.…”

“…In order to create the correct view of the environment, some pointing device is needed to indicate the viewer's vantage point, and head tracking is one of the most commonly used devices. Thus, in order to save scene-rendering time, which can otherwise be quite extensive, multi-resolutional VR displays are commonly used (for a recent review, see Luebke et al, 2002), and these are most often head-contingent (e.g., Ohshima, Yamamoto, & Tamura, 1996;Reddy, 1997;Watson et al, 1997). Reddy (1997, p. 181) has, in fact, argued that head tracking is often all that is needed to provide substantial savings in multi-resolutional VR displays, and he showed that taking account of retinal eccentricity created very little savings in at least two different VR applications (Reddy, 1997;Reddy, 1998).…”

“…Ideally, such a discrete resolution drop-off GCMRD research program would (1) test predictions of a model of human visual sensitivity that could be used to interpolate and extrapolate from the data, (2) parametrically and orthogonally vary the size of the D-AOI and level of resolution outside it, and (3) use a universally applicable resolution metric (e.g., cycles/degree). In fact, several human factors studies have used discrete resolution drop-off GCMRDs (Loschky & McConkie, 2000;Parkhurst et al, 2000;Watson et al, 1997), and each identified one or more combinations of D-AOI size and peripheral resolution that did not differ appreciably from a full highresolution control condition. However, none of the above studies meet all three of the above-stated criteria, and thus are of limited use for plotting a widely generalizable resolution drop-off function for use in GCMRDs.…”

“…Furthermore, if the drop-off is perceptible, what aspects of task performance, if any, are negatively impacted? Finally, further research should quantify the perception and performance costs associated with removing above-threshold peripheral resolution (i.e., detectably degraded GCMRDs) (for related studies and discussion see Kortum & Geisler, 1996b;Loschky, 2002;Loschky & McConkie, 2000;Parkhurst et al, 2000;Watson et al, 1997).…”