On So-Called Paradoxical Monocular Stereoscopy

Koenderink, Jan J.; Doorn, Andrea J. van; Kappers, Astrid M. L.

doi:10.1068/p230583

Cited by 117 publications

(127 citation statements)

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“…In the present study informal observations and comments made by participants suggested that some depth misperceptions occurred. If depth misjudgments occurred in such a task, future studies could use synoptic viewing (Koenderink, van Doorn & Kappers, 1994) to selectively remove binocular disparity, or prisms to selectively manipulate vergence information, showing which binocular cues were most important for these distance estimates. However, our current results are most consistent with a 'safety strategy' account.…”

Section: Discussionmentioning

confidence: 99%

Visual control of action in step descent

2008

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractVisual guidance of forwards, sideways, and upwards stepping has been investigated, but there is little knowledge about the visuomotor processes underlying stepping down actions. In this study we investigated the visual control of a single vertical step. We measured which aspects of the stepping down movement scaled with visual information about step height, and how this visual control varied with binocular vs monocular vision.Subjects stepped down a single step of variable and unpredictable height. Several kinematic measures were extracted including a new measure, 'kneedrop'. This describes a transition in the movement of the lower leg, which occurs at a point proportional to step height. In a within-subjects design measurements were made with either full vision, monocular vision, or no vision. Subjects scaled kneedrop relative to step height with vision, but this scaling was significantly impaired in monocular and no vision conditions.The study establishes a kinematic marker of visually controlled scaling in single-step locomotion which will allow further study of the visuomotor control processes involved in stepping down.

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Section: Discussionmentioning

confidence: 99%

Visual control of action in step descent

2008

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“…Binocular viewing of a picture generates a non-zero disparity field that specifies the shape of the flat picture surface. Synoptic viewing removes this non-zero disparity field and also delimits the field of view, thus reducing or eliminating picture surface visibility (Koenderink et al, 1994), as in monocular aperture viewing. Although viewing is binocular, the vergence signal is non-informative since synoptic viewing causes near-parallel orientation of the eyes (Koenderink et al, 1994) 16 .…”

Section: Other Methods Of Inducing Stereopsis In Static Picturesmentioning

confidence: 99%

“…If they did, pictures and photographs would not serve the ubiquitous purpose they do. Moreover, there is extensive empirical evidence that pictures convey a consistent and measurable percept of quantitative depth and 3-D shape (Koenderink, van Doorn & Kappers, 1994;Koenderink, van Doorn & Wagemans, 2011;Kubovy, 1986;Vishwanath, Girshick & Banks, 2005). The crucial difference between pictures and real scenes appears to lie in the presence or absence of a qualitative attribute (stereopsis) regardless of the actual 3-D relations perceived.…”

Section: Stereopsis and The Paradox Of Picture Perceptionmentioning

confidence: 99%

“…If this is true, the more ambiguous absolute depth values becomes (fewer cues, and/or less reliable distance information) the greater the regression of local depth estimates to the frontal plane, and the flatter the global depth relief implied by those local judgments. This can also explain why, despite differences in derived depth relief across viewing conditions and individual observers, spatial integration of local judgments reveal an internally consistent global 3-D shape, and important correlations and internal consistencies still obtain between viewing conditions and subjects (Koenderink et al, 1994(Koenderink et al, , 1995. It is also plausible that some types of depth judgements may partially access both types of representations.…”

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Toward a new theory of stereopsis.

Vishwanath¹

2014

Psychological Review

209

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Humans can obtain an unambiguous perception of depth and 3-dimensionality with one eye or when viewing a pictorial image of a 3-dimensional scene. However, the perception of depth when viewing a real scene with both eyes is qualitatively different: there is a vivid impression of tangible solid form and immersive negative space. This perceptual phenomenon, referred to as "stereopsis", has been among the central puzzles of perception since the time of da Vinci. After Wheatstone's invention of the stereoscope in 1838, stereopsis has conventionally been explained as a by-product of binocular vision or visual parallax. However, this explanation is challenged by the observation that the impression of stereopsis can be induced in single pictures under monocular viewing. Here I propose an alternative hypothesis that stereopsis is a qualitative visual experience related to the perception of egocentric spatial scale. Specifically, the primary phenomenal characteristic of stereopsis (the impression of 'real' separation in depth) is proposed to be linked to the precision with which egocentrically scaled depth (absolute depth) is derived. Since conscious awareness of this precision could help guide the planning of motor action, the hypothesis provides a functional account for the important phenomenal characteristic associated with stereopsis: the impression of interactability. By linking stereopsis to a generic perceptual attribute, rather than a specific cue, it provides a potentially more unified account of the variation of stereopsis in real scenes and pictures, and a basis for understanding why we can perceive depth in pictures despite conflicting visual signals. StereopsisVishwanath 3

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“…By the way, in the spatial domain anything that helps you to flatten the world will lead to better visual angle matching. So, for example, monocular viewing will probably help (Holway & Boring, 1941), as will using a synopter (Koenderink, van Doorn, & Kappers, 1994), and we know that inverting the scene will help you do better at visual angle matching. Now I want to make the same analogy in lightness, and if I can use a figure of speech, I will talk about flattening the illumination.…”

Section: Proximal Mode Perceptionmentioning

confidence: 99%

Theoretical Approaches to Lightness and Perception

Gilchrist

2015

Perception

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Abstract. Theories of lightness, like theories of perception in general, can be categorized as highlevel, low-level, and mid-level. However, I will argue that in practice there are only two categories: one-stage mid-level theories, and two-stage low-high theories. Low-level theories usually include a high-level component and high-level theories include a low-level component, the distinction being mainly one of emphasis. Two-stage theories are the modern incarnation of the persistent sensation/ perception dichotomy according to which an early experience of raw sensations, faithful to the proximal stimulus, is followed by a process of cognitive interpretation, typically based on past experience. Like phlogiston or the ether, raw sensations seem like they must exist, but there is no clear evidence for them. Proximal stimulus matches are postperceptual, not read off an early sensory stage. Visual angle matches are achieved by a cognitive process of flattening the visual world. Likewise, brightness (luminance) matches depend on a cognitive process of flattening the illumination. Brightness is not the input to lightness; brightness is slower than lightness. Evidence for an early (< 200 ms) mosaic stage is shaky. As for cognitive influences on perception, the many claims tend to fall apart upon close inspection of the evidence. Much of the evidence for the current revival of the 'new look' is probably better explained by (1) a natural desire of (some) subjects to please the experimenter, and (2) the ease of intuiting an experimental hypothesis. High-level theories of lightness are overkill. The visual system does not need to know the amount of illumination, merely which surfaces share the same illumination. This leaves mid-level theories derived from the gestalt school. Here the debate seems to revolve around layer models and framework models. Layer models fit our visual experience of a pattern of illumination projected onto a pattern of reflectance, while framework models provide a better account of illusions and failures of constancy. Evidence for and against these approaches is reviewed.

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On So-Called Paradoxical Monocular Stereoscopy

Cited by 117 publications

References 10 publications

Visual control of action in step descent

Visual control of action in step descent

Toward a new theory of stereopsis.

Theoretical Approaches to Lightness and Perception

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