The Role of Optical Expansion Patterns in Locomotor Control

Johnston, Ian; White, Glenton R.; Cumming, Ronald W.

doi:10.2307/1421439

Cited by 115 publications

(71 citation statements)

References 11 publications

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“…Performance is the same, regardless of whether the vertical target line is visible during the movement of the points. Observers perform better when higher speeds of translation are simulated, consistent with earlier observations by Johnston, White andCumming (1973), andCarel (1961). Hannon (1988, 1990) compared performance under three conditions: (1) the observer fixated a stationary marker on the display, and the displays only simulated pure translation of the observer, (2) the observer tracked a moving point in the display, thus introducing a rotational component of motion, and (3) the display itself contained both translational and rotational components of motion, and the observer was required to maintain stationary fixation.…”

Section: The Perception Of Observer Translationsupporting

confidence: 89%

“…Subjectively, observers perceived themselves as moving toward the point of fixation, which would correspond to a center of outflowing motion in this case. Similar observations regarding movement toward a frontoparallel plane were made in other studies (Llewellyn, 1971;Johnston et al, 1973;Regan & Beverley, 1982;Rieger & Toet, 1985;Cutting, 1938). This observation suggests first, that extraretinal information regarding eye rotation is used in the analysis of heading direction, and second, that the passive decoupling of the rotational and translational components of motion from visual input alone requires differential motion produced by elements at different depths.…”

Section: The Perception Of Observer Translationsupporting

confidence: 85%

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Recovering Heading for Visually-Guided Navigation

Hildreth¹

1991

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We presep~t a model for recovering the direction of heading of an observer who is moving relative to a scene that may contain self-moving objects. The model builds upon an algorithm proposed by Rieger and Lawton (1985), which is based cn earlier work by Longuet-Higgins and Prazdny (198i). The algorithm uses velocity differences computed in regions of high depth variation to estimate the location of the focus of ezpan3ion, which indicates the observer's heading direction. We relate the behavior of the proposed model to psychophysical observations regarding the ability of human observers to judge their heading direction, and show how the model can cope with selfmoving objects in the environment. We also discuss this model in the broader context of a navigational system that performs tasks requiring rapid sensing and response through the interaction of simple task-specific routines.@Massachusetts Institute of Technology" (1991)

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Section: The Perception Of Observer Translationsupporting

confidence: 89%

Section: The Perception Of Observer Translationsupporting

confidence: 85%

Recovering Heading for Visually-Guided Navigation

Hildreth¹

1991

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“…The earlier literature on heading judgments asked observers, at the end of a translational flow sequence, to point in their direction ofsimulated self-movement (Johnston, White, & Cumming, 1973;Llewellyn, 1971;R. Warren, 1976).…”

Section: Aimpoints Heading Directions and Perceived Pathsmentioning

confidence: 99%

Heading and path information from retinal flow in naturalistic environments

Cutting

Vishton

Flückiger

et al. 1997

Perception & Psychophysics

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In four experiments, we explored the heading and path information available to observers as we simulated their locomotion through a cluttered environment while they fixated an object off to the side. Previously, we presented a theory about the information available and used in such situations. For such a theory to be valid, one must be sure of eye position, but we had been unable to monitor gaze systematically; in Experiment I, we monitored eye position and found performance best when observers fixated the designated object at the center of the display. In Experiment 2, when we masked portions of the display, we found that performance generally matched the amount of display visible when scaled to retinal sensitivity. In Experiments 3 and 4, we then explored the metric of information about heading (nominal vs. absolute) available and found good nominal information but increasingly poor and biased absolute information as observers looked farther from the aimpoint. Part of the cause for this appears to be that some observers perceive that they have traversed a curved path even when taking a linear one. In all cases, we compared our results with those in the literature.How do we negotiate cluttered environments during our daily activities? How is it that we can generally do this with relative ease and without injury? What information subserves the determination of our direction ofmovement, often called heading? For over a decade, we have been developing a theory of wayfinding based on the use of particular sources of information in retinal flow, the complex of motion and displacement information projected to the retina of an individual moving through a rigid environment while fixating an object somewhat offhis or her path (Cutting, 1986(Cutting, , 1996Cutting, Springer, Braren, & Johnson, 1992; Cutting, Vishton, & Braren, 1995;. Strategically, we have simulated naturalistic environments relatively rich in sources of information about layout-occlusion, relative size, relative density, height in the visual field, in addition to motion perspective.'We thank

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“…Early studies used analog shadow-casting systems to simulate the optical flow seen during linear translation (Kaufman, 1968;Llewellyn, 1971), and later ones used computer graphics technology (Johnston, White, & Cumming, 1973;R. Warren, 1976).…”

Section: A Selective History Of Heading Researchmentioning

confidence: 99%

“…One variety has simulated only translational motion in the optical array (Johnston et al, 1973;Kaufman, 1968;Llewellyn, 1971;van den Berg & Brenner, 1994;R. Warren, 1976;W.…”

Section: A Selective History Of Heading Researchmentioning

confidence: 99%