Part Boundaries Alter the Perception of Transparency

1998 ◽  
Vol 9 (5) ◽  
pp. 370-378 ◽  
Author(s):  
Manish Singh ◽  
Donald D. Hoffman
Keyword(s):  
Apparent Motion ◽  
Structure From Motion ◽  
Human Vision ◽  
Visual Direction ◽  
Visual Objects ◽  
Minima Rule

The perception of transparency is a remarkable feat of human vision: A single stimulation at the retina is interpreted as arising from two (or more) distinct surfaces, separated in depth, in the same visual direction. This feat is intriguing because physical transparency is neither necessary nor sufficient for phenomenal transparency. Many conditions for phenomenal transparency have been studied, including luminance, chromaticity, stereo depth, apparent motion, and structure from motion. Figural conditions have also been studied, primarily by Gestalt psychologists, resulting in descriptive laws. Here we extend, and make precise, these laws using the genericity principle and the minima rule for part boundaries. We report experiments that support the psychological plausibility of these refinements. The results suggest that the formation of visual objects and their parts is an early process in human vision that can precede the representation of transparency.

Inferring Structure from Motion in Two-View and Multiview Displays

Perception ◽  
1993 ◽  
Vol 22 (12) ◽  
pp. 1441-1465 ◽  
Author(s):  
Jeffrey C Liter ◽  
Myron L Braunstein ◽  
Donald D Hoffman
Keyword(s):  
Relative Motion ◽  
Apparent Motion ◽  
Structure From Motion ◽  
Three Dimensional ◽  
Rigid Motion ◽  
Parameter Family ◽  
Image Motion ◽  
Heuristic Analysis

Five experiments were conducted to examine constraints used to interpret structure-from-motion displays. Theoretically, two orthographic views of four or more points in rigid motion yield a one-parameter family of rigid three-dimensional (3-D) interpretations. Additional views yield a unique rigid interpretation. Subjects viewed two-view and thirty-view displays of five-point objects in apparent motion. The subjects selected the best 3-D interpretation from a set of 89 compatible alternatives (experiments 1–3) or judged depth directly (experiment 4). In both cases the judged depth increased when relative image motion increased, even when the increased motion was due to increased simulation rotation. Subjects also judged rotation to be greater when either simulated depth or simulated rotation increased (experiment 4). The results are consistent with a heuristic analysis in which perceived depth is determined by relative motion.

The role of brachial muscle spindle signals in assignment of visual direction

1993 ◽  
Vol 70 (4) ◽  
pp. 1578-1584 ◽  
Author(s):  
P. DiZio ◽  
C. E. Lathan ◽  
J. R. Lackner
Keyword(s):  
Apparent Motion ◽  
Muscle Spindle ◽  
Target Location ◽  
Biceps Brachii ◽  
Visual Target ◽  
Visual Direction ◽  
Muscle Vibration ◽  
Illusory Motion ◽  
The Stability

1. In the oculobrachial illusion, a target light attached to the unseen stationary hand is perceived as moving and changing spatial position when illusory motion of the forearm is elicited by brachial muscle vibration. Our goal was to see whether we could induce apparent motion and displacement of two retinally fixed targets in opposite directions by the use of oculobrachial illusions. 2. We vibrated both biceps brachii, generating illusory movements of the two forearms in opposite directions, and measured any associated changes in perceived distance between target lights on the unseen stationary hands. The stability of visual fixation of one of the targets was also measured. 3. The seen distance between the stationary targets increased significantly when vibration induced an illusory increase in felt distance between the hands, both with binocular and monocular viewing. 4. Subjects maintained fixation accuracy equally well during vibration-induced illusory increases in visual target separation and in a no-vibration control condition. Fixation errors were not correlated with the extent or direction of illusory visual separation. 5. These findings indicate that brachial muscle spindle signals can contribute to an independent representation of felt target location in head-centric coordinates that can be interrelated with a visual representation of target location generated by retinal and oculomotor signals. 6. A model of how these representations are interrelated is proposed, and its relation to other intersensory interactions is discussed.

Pulfrich Effect and the Filling in of Apparent Motion

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Michael J Morgan
Keyword(s):  
Eye Movements ◽  
Apparent Motion ◽  
Visual Direction ◽  
Moving Target ◽  
Alignment Technique ◽  
Pulfrich Effect ◽  
Series Of Experiments ◽  
Tracking Eye Movements ◽  
As If

In the stroboscopic version of the Pulfrich effect a filter is able to induce depth shifts in a target as if the latter were moving continuously, rather than merely occupying a series of discrete positions. This was examined in a further series of experiments, in which a visual alignment technique was used to measure the perceived visual direction of an apparently moving target in intervals between its presentations. Results showed that the target has approximately the visual direction that it would have if it were moving continuously. This ‘filling in’ of apparent motion was shown to occur before the level of stereopsis. The possible influence of tracking eye movements is discussed.

A Structure-from-Motion Scheme That Looks for Parallels, and its Implications for Apparent Reversals in Rotating Trapezia

Perception ◽  
1995 ◽  
Vol 24 (8) ◽  
pp. 867-877
Author(s):  
Roddy Cowie
Keyword(s):  
Structure From Motion ◽  
Human Vision ◽  
General Algorithm ◽  
Considerable Range

Apparent reversals in rotating trapezia have been regarded as evidence that human vision favours methods which are heuristic or form dependent. However, the argument is based on the assumption that general algorithmic methods would avoid the illusion, and that has never been clear. A general algorithm for interpreting moving parallels has been developed to address the issue. It handles a considerable range of stimuli successfully, but finds multiple interpretations in situations which correspond closely to those where apparent reversals occur. This strengthens the hypothesis that apparent reversals may occur when general algorithmic methods fail and heuristics are invoked as a stopgap.

Aftereffects of Apparent Motion: The Existence of an AND-Type Binocular System in Human Vision

Perception ◽  
1994 ◽  
Vol 23 (9) ◽  
pp. 1069-1083 ◽  
Author(s):  
Noud A W H van Kruysbergen ◽  
Charles M M de Weert
Keyword(s):  
Apparent Motion ◽  
Type System ◽  
Experimental Results ◽  
Human Vision ◽  
Test Conditions

There has been evidence for the existence of a purely binocular system in human vision that acts as an AND gate on information from the two eyes. There also has been evidence for the nonexistence of such a purely binocular system, indicating only the existence of an OR-type binocular system that responds to input from one or both eyes. As a result there are a number of possible explanations for the differing experimental results: the binocular system is an OR-type system only, it is a facilitating OR system that has AND-type characteristics, or it consists of independent OR and AND subsystems. Monocular adaptation, alternating monocular adaptation, or binocular adaptation were used to demonstrate the existence of the different systems, but in none of the previous experiments was the AND-type binocular system activated directly, and the existence of this AND system was deduced mostly because of differences in aftereffect strengths between monocular and binocular test conditions. Experiments are reported in which stimuli that activate the AND-type binocular system explicitly have been used, and the results show that we need the existence of such an AND-type binocular system to account for the results.

Relationships between Channels for Colour and Spatial Frequency in Human Vision

Perception ◽  
1973 ◽  
Vol 2 (1) ◽  
pp. 31-40 ◽  
Author(s):  
V Virsu ◽  
S Haapasalo
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Human Vision ◽  
Visual Objects ◽  
The Third ◽  
Simultaneous Integration ◽  
Two Systems ◽  
Channel Systems

Five forms of relationships and four types of channels are possible between two systems of sensory channels. The relationships between channels for colour and spatial frequency were studied in three adaptation experiments. In the first, a new colour-specific spatial aftereffect was found, which indicates the existence of channels that are specific both to colour and to spatial frequency. The second showed that the spatial-frequency aftereffect of Blakemore and Sutton is not colour specific, which indicates that there are channels for spatial frequency that are not colour specific. The third demonstrated that coloured afterimages are not spatial-frequency specific immediately after adaptation, although they become so later. This indicates that there are channels for colour that are not spatial-frequency specific. The existence of these three types of channels implies that the channel systems for colour and spatial frequency overlap partially and mutually in the human visual system. This kind of organisation of channel systems, if it exists, may form the psychophysical structure that is required for the capacity of simultaneous integration and differentiation in the perception of colour and size of visual objects.

scholarly journals Two Types of Visual Objects

Studia Humana ◽  
2015 ◽  
Vol 4 (2) ◽  
pp. 26-38
Author(s):  
Błażej Skrzypulec
Keyword(s):  
Cognitive Psychology ◽  
Visual Persistence ◽  
Human Vision ◽  
Visual Objects ◽  
Visual Organization ◽  
The One

Abstract While it is widely accepted that human vision represents objects, it is less clear which of the various philosophical notions of ‘object’ adequately characterizes visual objects. In this paper, I show that within contemporary cognitive psychology visual objects are characterized in two distinct, incompatible ways. On the one hand, models of visual organization describe visual objects in terms of combinations of features, in accordance with the philosophical bundle theories of objects. However, models of visual persistence apply a notion of visual objects that is more similar to that endorsed in philosophical substratum theories. Here I discuss arguments that might show either that only one of the above notions of visual objects is adequate in the context of human vision, or that the category of visual objects is not uniform and contains entities properly characterized by different philosophical conceptions.

scholarly journals Time-locked Perceptual Fading Induced by Visual Transients

2003 ◽  
Vol 15 (5) ◽  
pp. 664-672 ◽  
Author(s):  
Ryota Kanai ◽  
Yukiyasu Kamitani
Keyword(s):  
Apparent Motion ◽  
Visual Awareness ◽  
Luminance Contrast ◽  
Target Object ◽  
Visual Object ◽  
Visual Objects ◽  
Visual Inputs ◽  
Low Luminance ◽  
Target Disk ◽  
Unique Mechanism

After prolonged fixation, a stationary object placed in the peripheral visual field fades and disappears from our visual awareness, especially at low luminance contrast (the Troxler effect). Here, we report that similar fading can be triggered by visual transients, such as additional visual stimuli flashed near the object, apparent motion, or a brief removal of the object itself (blinking). The fading occurs even without prolonged adaptation and is time-locked to the presentation of the visual transients. Experiments show that the effect of a flashed object decreased monotonically as a function of the distance from the target object. Consistent with this result, when apparent motion, consisting of a sequence of flashes was presented between stationary disks, these target disks perceptually disappeared as if erased by the moving object. Blinking the target disk, instead of flashing an additional visual object, turned out to be sufficient to induce the fading. The effect of blinking peaked around a blink duration of 80 msec. Our findings reveal a unique mechanism that controls the visibility of visual objects in a spatially selective and time-locked manner in response to transient visual inputs. Possible mechanisms underlying this phenomenon will be discussed.

scholarly journals A Mathematical Principle of Art and Human Vision

2020 ◽  
Author(s):  
Xin Zhang
Keyword(s):  
Fourier Analysis ◽  
Mathematical Theory ◽  
Visual Illusions ◽  
Human Vision ◽  
Mathematical Principle ◽  
Frequency Filtering ◽  
Human Visual Perception ◽  
Visual Objects ◽  
Geometrical Illusions ◽  
Shed Light

The study of visual illusions is an old subject and an important part of the psychology of human visual perception, but hitherto there has been no single principle able to explain radically different kinds of visual illusions conjointly. Such a principle does exist, as is to be shown, and has the virtue of being rigorous: it is the mathematical theory of Fourier analysis. A great many visual illusions are what happen when the visual objects involved undergo certain frequency filtering, a concept deduced from Fourier analysis. Phenomena thus explained belong in these distinct categories: brightness illusions, colour illusions, geometrical illusions, and motion illusions, all of which have been simulated with computer programmes based on this mathematical principle. Visual illusions obeying this principle have in fact been depicted in Western painting for centuries, and art can in certain ways shed light on the quest for the understanding of human vision.

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