Optic flow and the metric of the visual ground plane

Beusmans, Jack M. H.

doi:10.1016/s0042-6989(97)00285-x

Cited by 41 publications

(46 citation statements)

References 37 publications

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“…Another result obtained by Loomis and Philbeck (1999) is that the degree of perceptual distortion increased slightly with egocentric distance of the L-shaped objects, a result also apparent in the extent matching results of Beusmans (1998) and Loomis et al (1992). At first glance, it might appear that the increasing perceptual shape distortion with distance is the consequence of diminishing effectiveness of distance cues, such as accommodation, convergence, and binocular disparity.…”

mentioning

confidence: 87%

Dissociation between location and shape in visual space.

Loomis

Philbeck

Zahorik

2002

Journal of Experimental Psychology: Human Perception and Perfor

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There are often large perceptual distortions of shapes lying on the ground plane, even in well-lit environments. These distortions occur under conditions for which the perception of location i saccurate. Four hypotheses are considered for reconciling these seemingly paradoxical results, after which 2 experiments are reported that lend further support to 1 of them--that perception of shapeand perception of location are sometimes dissociable. The 2 experiments show that whereas perception of location does not depend on whether viewing is monocular or binocular (when other distance cues are abundant), perception of shape becomes more veridical when viewing is binocular. This means that perception of shape is not fully constrained by the perceived locations of the vertices that define the shape.

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confidence: 87%

Dissociation between location and shape in visual space.

Loomis

Philbeck

Zahorik

2002

Journal of Experimental Psychology: Human Perception and Perfor

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“…Optic flow cannot give information about absolute distance to an object and travel speed. Rather it can be used to compare spatial intervals [25] and for time measurements relative to the object and observer-the time-to-contact [6,26] (but see also [7]). Under certain conditions, optic flow has been shown to be a reliable cue to estimate distance of travel [27,28].…”

Section: Visual Cuesmentioning

confidence: 99%

Evaluating perception in driving simulation experiments

Kemeny

Panerai

2003

Trends in Cognitive Sciences

266

147

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The use of driving simulation for vehicle design and driver perception studies is expanding rapidly. This is largely because simulation saves engineering time and costs, and can be used for studies of road and traffic safety. How applicable driving simulation is to the real world is unclear however, because analyses of perceptual criteria carried out in driving simulation experiments are controversial. On the one hand, recent data suggest that, in driving simulators with a large field of view, longitudinal speed can be estimated correctly from visual information. On the other hand, recent psychophysical studies have revealed an unexpectedly important contribution of vestibular cues in distance perception and steering, prompting a re-evaluation of the role of visuo-vestibular interaction in driving simulation studies.Vehicle driving implies perception and control of selfmotion at a greater range of velocities than locomotion by walking. It is often considered to be a task dominated by visual information. However, it is well-established that other sensory information, such as that provided by the vestibular and PROPRIOCEPTIVE (see Glossary) channels, also contributes to the perception and control of selfmotion. Motivated by a recent renewed interest in the role and function of these non-visual sensory modalities, we aim in this review to re-evaluate the role of visuovestibular interactions in driving simulation experiments, and to assess how applicable driving simulation is to the real world for studies of vehicle dynamics or driver behaviour.In 1938 Gibson [1] proposed a psychophysical theory of perception for automobile-driving, defining a 'terrain of field of space' for the driver, with the car considered as a tool of locomotion and the driver aiming to drive in the middle of a 'field of safe travel'. In 1950 he described the visual perception of space [2] based on visual depth, distance or orientation stimulus variables. OPTIC FLOW, one of the most important visual cues he proposed, is defined as the visual motion experienced as a result of walking or driving, and it is thought to play a dominant role in the control of heading [3] and collision detection [4 -7]. However, regarding the control of the direction of movement in natural environments (i.e. walking), there is still disagreement over whether the structure of the flow [8,9] or the visual EGOCENTRIC DIRECTION per se [10,11] is the dominant source of information. It is not clear either whether the same strategies used for natural locomotion apply to driving situations where displacements occur at higher velocities. Interestingly, a new point of view on these controversial issues was recently provided by experiments performed in driving simulators [12]. However, Gibson's original theory also included a definition of the perceptual field of the car itself, bringing to the driver kinaesthetic and tactile cues. These ideas were applied to driving simulation from the early 1980s [13][14][15], and since then many simulator experiments have been carried out for...

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“…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).…”

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confidence: 99%

The visual perception of lines on the road

Shaffer

Maynor

Roy

2008

Perception & Psychophysics

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The present work demonstrates that observers grossly underestimate the length of lines parallel to their line of sight. In Experiment 1, observers, working from memory, estimated the length of a dashed line on the road to be 0.61 m. This result is consistent with observers' using an average visual angle converted to the physical length of visible lines on the road to estimate their length. In Experiment 2, observers gave verbal and matching estimates that significantly underestimated the length of a 3.05-m line on the ground that was parallel to their line of sight. In Experiment 3, observers significantly underestimated the length of dashed lines on the road while in a moving car. The results of Experiments 1 and 3 are described well by Euclidean geometry, whereas the tangle model that utilizes an increasing function of the visual angle to describe perceived extent best describes the results of Experiment 2.

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Optic flow and the metric of the visual ground plane

Cited by 41 publications

References 37 publications

Dissociation between location and shape in visual space.

Dissociation between location and shape in visual space.

Evaluating perception in driving simulation experiments

The visual perception of lines on the road

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