The effect of viewing position on the perceived layout of space

Abstract

Eight observers judged the location of 13 objects in an open field by drawing a map of the scene, estimating absolute distances between objects, and rank ordering subsets of distances. Half the observers made judgments twice from the same position while the rest moved 90°around the scene before making the second set of judgments. Scaled judgments showed a strong visible similarity to the actual spatial layout of the scene. Observer judgments changed significantly as a function of observer position. A portion of this effect was due to a perceptual shortening of radial distances. These results were taken to support the classical psychophysical model of space perception rather than a strong ecological model and to emphasize the importance of the subjective element of visual space perception.

The visual perception of lines on the road

“…These results generally fit with previous findings that have shown how visual space is distorted in an affine manner, so that perceived intervals in depth appear to become systematically compressed with depth, relative to perceived intervals in the horizontal or vertical direction (Beusmans, 1998;Foley et al, 2004;Gilinsky, 1951;Gogel, 1964;Haber, 1985;Harway, 1963;Hecht et al, 1999;Kudoh, 2005;Loomis et al, 1992;Loomis & Philbeck, 1999;Matsushima et al, 2005;Norman et al, 2005;Norman et al, 1996;Todd & Norman, 2003;Todd et al, 1995;Toye, 1986;Wagner, 1985).…”

“…They typically have observers either estimate distances between stakes or adjust a stake or one part of the L-shape so that a depth interval is perceived to be equivalent to a horizontal interval. This work has shown that in cases in which stakes are ~4-40 m away from the observer, depth intervals are adjusted to be between 1.5 and 2 times as large, relative to the horizontal interval of the same physical size (Foley et al, 2004;Hecht et al, 1999;Kudoh, 2005;Loomis et al, 1992;Loomis & Philbeck, 1999;Matsushima et al, 2005;Norman et al, 2005;Toye, 1986;Wagner, 1985). Hecht et al concluded that many findings from other studies could be rephrased in terms of depth compression and suggested that there is a general mechanism for sagittal compression for far space.…”

“…Although some of this work has focused on the metrics of visual space in general and has shown that visual space is curved (i.e., hyperbolic or elliptical; Battro, Netto, & Rozestraten, 1976;Blank, 1958;Koenderink, van Doorn, & Lappin, 2000;Luneburg, 1950), an abundance of other work has focused on how visual space is distorted in an affine manner, so that perceived intervals in depth (or parallel to the observer's line of sight) appear to become systematically compressed with depth, relative to perceived intervals in the horizontal or vertical directions (i.e., the frontoparallel plane perpendicular to the observer's line of sight; Beusmans, 1998;Foley, Ribeiro-Filho, & Da Silva, 2004;Gilinsky, 1951;Gogel, 1964;Haber, 1985;Harway, 1963;Hecht, van Doorn, & Koenderink, 1999;Kudoh, 2005;Loomis, Da Silva, Fujita, & Fukusima, 1992;Loomis & Philbeck, 1999;Matsushima, de Oliveira, Ribeiro-Filho, & Da Silva, 2005;Norman, Crabtree, Clayton, & Norman, 2005;Norman, Todd, Perotti, & Tittle, 1996;Todd & Norman, 2003;Todd, Tittle, & Norman, 1995;Toye, 1986;Wagner, 1985). Some of this work has shown that when extents are viewed in near space, depth intervals must be made approximately 1.5-2 times as large to be perceived to be the same as horizontal extents (Norman et al, 1996;Todd & Norman, 2003).…”

Frontal extents in virtual environments are not immune to underperception

“…Error bars represent ±1 SEM. The dotted line at 1.0 represents veridical performance indicating a linear relationship between stimulus orientation and perceived exocentric extent (Foley et al, 2004;Levin & Haber, 1993;Toye, 1986;Wagner, 1985). In both the grass VE and the room VE, the relationship between distance judgment ratio and stimulus orientation was well described by a linear function (grass: slope = −.072, R 2 = .98; room: slope = −.077, R 2 = .97).…”

“…When viewed under full-cue conditions in the real world, judgments of exocentric extents containing both frontal and depth components have been described as an approximately linear combination of judgments of pure frontal and pure depth extents (Foley, Ribeiro-Filho, & Da Silva, 2004;Levin & Haber, 1993;Toye, 1986;Wagner, 1985). In light of the possibility that depth extents in the VEs will be underperceived and frontal extents will be accurately perceived (replicating results of Geuss et al), we also included stimuli containing both frontal and depth components to evaluate whether the shift from underperception to accurate perception is graded or discrete.…”