scholarly journals The role of motion parallax in the perception of egocentric direction

2017 ◽  
Vol 17 (10) ◽  
pp. 985
Author(s):  
Kait Clark ◽  
Simon Rushton
Keyword(s):  
Motion Parallax ◽  
Egocentric Direction

Apparent Depth with Retinal Image Motion of Expansion and Contraction Yoked to Head Movement

Perception ◽  
1998 ◽  
Vol 27 (8) ◽  
pp. 937-949 ◽  
Author(s):  
Takanao Yajima ◽  
Hiroyasu Ujike ◽  
Keiji Uchikawa
Keyword(s):  
Motion Parallax ◽  
Ccd Camera ◽  
Head Movements ◽  
Image Motion ◽  
Apparent Depth ◽  
Motion Cues ◽  
Relative Expansion ◽  
Retinal Image Motion ◽  
Self Motion

The two main questions addressed in this study were (a) what effect does yoking the relative expansion and contraction (EC) of retinal images to forward and backward head movements have on the resultant magnitude and stability of perceived depth, and (b) how does this relative EC image motion interact with the depth cues of motion parallax? Relative EC image motion was produced by moving a small CCD camera toward and away from the stimulus, two random-dot surfaces separated in depth, in synchrony with the observers' forward and backward head movements. Observers viewed the stimuli monocularly, on a helmet-mounted display, while moving their heads at various velocities, including zero velocity. The results showed that (a) the magnitude of perceived depth was smaller with smaller head velocities (<10 cm s−1), including the zero-head-velocity condition, than with a larger velocity (10 cm s−1), and (b) perceived depth, when motion parallax and the EC image motion cues were simultaneously presented, is equal to the greater of the two possible perceived depths produced from either of these two cues alone. The results suggested the role of nonvisual information of self-motion on perceiving depth.

The Familiar-Size Cue to Depth under Reduced-Cue Viewing Conditions

Perception ◽  
1994 ◽  
Vol 23 (11) ◽  
pp. 1301-1312 ◽  
Author(s):  
John Predebon ◽  
Jacob Steven Woolley
Keyword(s):  
Motion Parallax ◽  
Verbal Report ◽  
Major Determinant ◽  
Relative Distance ◽  
Head Motion ◽  
Familiar Size ◽  
Verbal Reports ◽  
Direct Reports ◽  
Visual Conditions

The familiar-size cue to perceived depth was investigated in five experiments. The stimuli were stationary familiar objects viewed monocularly under otherwise completely darkened visual conditions. Perceived depth was measured directly with the method of verbal report and indirectly with the head-motion procedure. Although the familiar-size cue influenced verbal reports of the distances of the objects, it did not determine perceived depth as assessed with the head-motion procedure. These findings support the claim that familiar size is not a major determinant of perceived depth, and that cognitive or nonperceptual factors mediate the effects of familiar size on direct reports of depth and distance. Possible reasons for the failure of familiar size to influence the head-motion-derived measures of perceived depth are discussed with particular emphasis on the role of motion parallax in determining perceptions of depth and relative distance.

The effect of overall stimulus velocity on motion parallax

2008 ◽  
Vol 25 (1) ◽  
pp. 3-15 ◽  
Author(s):  
YING ZHANG ◽  
PETER H. SCHILLER
Keyword(s):  
Motion Parallax ◽  
Three Dimensional ◽  
Reaction Times ◽  
Visual Display ◽  
Stimulus Movement ◽  
Stimulus Velocity ◽  
Target Region ◽  
Performance Accuracy ◽  
Dimensional Object

This study examined the effectiveness with which motion parallax information can be utilized by rhesus monkeys for depth perception. A visual display comprised of random-dots that mimicked a rigid, three-dimensional object rocking back and forth was used. Differential depth was produced by presenting sub-regions of the dots moving at different velocities from the rest of dots in the display. The tasks for the monkeys were to detect or discriminate a target region that was protruding the furthest from the background plane. To understand the role of stimulus movement, we examined the accuracy and the rapidity of the saccadic responses as a function of rocking velocity of the entire three-dimensional object. The results showed that performance accuracy improved and reaction times decreased with increasing rocking velocities. The monkeys can process the motion parallax information with remarkable rapidity such that the average reaction time ranged between 212 and 246 milliseconds. The data collected suggest that the successive activation of just two sets of cones is sufficient to perform the task.

The Effect of Observer Perspective on the Perceived Velocity of Human Walkers

2004 ◽  
Vol 63 (3) ◽  
pp. 191-199 ◽  
Author(s):  
Esther Schollerer ◽  
Rudolf Groner
Keyword(s):  
Motion Parallax ◽  
Apparent Velocity ◽  
Motion Cues ◽  
Factorial Anova ◽  
Observer Perspective ◽  
Main Effect ◽  
Perceived Velocity

The apparent velocity of a filmed person, walking in front of static or moving backgrounds, was estimated in 2 experiments by 18 observers. The camera either followed the walker or remained at the same position (= stabilized vs. mobile observer perspective). A factorial ANOVA was used with the estimate of the walker’s velocity (in km/h) as dependent variable. Based on the number of applicable motion cues and on the role of motion parallax, it was predicted that the mobile observer perspective should lead to a higher estimate of the walker’s velocity. In both experiments, the opposite of this prediction was observed: Stabilized observer perspective produced consistently higher velocity estimates as a main effect and in interaction with the background variables. No velocity increasing effect of motion parallax was found in stabilized observer perspective, presumably because of the ambiguity of motion cues with respect to background distance.

A Distinctive Characteristic of Pictorial Perception: The Zoom Effect

Perception ◽  
1978 ◽  
Vol 7 (6) ◽  
pp. 625-633 ◽  
Author(s):  
Margaret A Hagen ◽  
Harry B Elliott ◽  
Rebecca K Jones
Keyword(s):  
Surface Texture ◽  
Flat Surface ◽  
Motion Parallax ◽  
Linear Perspective ◽  
Head Motion ◽  
Surface Information ◽  
Pictorial Perception

To investigate the role of flat surface information for the plane of projection in pictorial perception, three studies were designed in which varying amounts of such information were made available to adult subjects. The first study tested preferences for true or modified linear perspective under conditions of presence or absence of surface texture cues for the plane of projection. In the second and third studies, the absence of texture cues for the plane was coupled with the addition of motion parallax and binocular information respectively. It was found that adults showed a consistent preference for parallel perspective in pictures when the flat-surface information was provided either by visible texture or by motion parallax; but no consistent preference for either true or modified perspective in the absence of all three sources of flatness information or when the flat surface information was given only by binocular cues in the absence of visible surface texture or head motion.

Motion Parallax, Relative Size, and Benussi Effect

1993 ◽  
Vol 76 (3_suppl) ◽  
pp. 1320-1322 ◽  
Author(s):  
Willard L. Brigner ◽  
James R. Deni
Keyword(s):  
Motion Parallax ◽  
Relative Size ◽  
Apparent Depth

Many observers perceive depth when a configuration of nonconcentric circles is rotated on a disc. While it has been suggested by a number of investigators that motion parallax has a role in generating this phenomenon, the supporting data are equivocal. The current study proposed that the ambiguity regarding the role of motion parallax may have arisen because there are contradictions between relative size cues and motion parallax cues in the configuration of rotating circles. However, with 17 undergraduate observers, apparent depth was no more reliably reported with consistent cues of motion parallax and relative size than when these cues were contradictory.

The Role of Stereopsis, Motion Parallax, Perspective and Angle Polarity in Perceiving 3-D Shape

2012 ◽  
Vol 25 (3-4) ◽  
pp. 263-285 ◽  
Author(s):  
Aleksandra Sherman ◽  
Thomas V. Papathomas ◽  
Anshul Jain ◽  
Brian P. Keane
Keyword(s):  
Motion Parallax

scholarly journals Environmental anchoring of grid-like representations minimizes spatial uncertainty during navigation

2017 ◽  
Author(s):  
Tobias Navarro Schröder ◽  
Benjamin W. Towse ◽  
Matthias Nau ◽  
Neil Burgess ◽  
Caswell Barry ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Motion Parallax ◽  
Grid Cell ◽  
Cell System ◽  
Neural Mechanisms ◽  
Spatial Uncertainty ◽  
Grid System ◽  
Virtual Navigation ◽  
Human Participants

SummaryMinimizing spatial uncertainty is essential for navigation, but the neural mechanisms remain elusive. Here we combine predictions of a simulated grid cell system with behavioural and fMRI measures in humans during virtual navigation. First, we showed that polarising cues produce anisotropy in motion parallax. Secondly, we simulated entorhinal grid cells in an environment with anisotropic information and found that self-location is decoded best when grid-patterns are aligned with the axis of greatest information. Thirdly, when exposing human participants to polarised virtual reality environments, we found that navigation performance is anisotropic, in line with the use of parallax. Eye movements showed that participants preferentially viewed polarising cues, which correlated with navigation performance. Finally, using fMRI we found that the orientation of grid-cell-like representations in entorhinal cortex anchored to the environmental axis of greatest parallax information, orthogonal to the polarisation axis. In sum, we demonstrate a crucial role of the entorhinal grid system in reducing uncertainty in representations of self-location and find evidence for adaptive spatial computations underlying entorhinal representations in service of optimal navigation.

scholarly journals Estimating depth and distance in reach space: the role of head motion parallax

2010 ◽  
Vol 2 (7) ◽  
pp. 700-700
Author(s):  
A. M. Plooy ◽  
J. P. Wann
Keyword(s):  
Motion Parallax ◽  
Head Motion ◽  
Reach Space

Visual figure–ground discrimination in the honeybee: the role of motion parallax at boundaries

1990 ◽  
Vol 238 (1293) ◽  
pp. 331-350 ◽  
Keyword(s):  
Apparent Motion ◽  
Motion Parallax ◽  
The Other ◽  
Neural Models ◽  
Height Difference ◽  
Sugar Water ◽  
Different Types ◽  
Series Of Experiments ◽  
The Difference

Free flying bees were trained to collect a reward of sugar-water from a structured figure, placed at a randomly varying location on a sheet of transparent Perspex, positioned 5 cm above a structured Background. During subsequent tests, done in the absence of a reward, the bees’ landings on the boundaries of the figure, as well as within the figure and outside it, were recorded. The same bees were also tested with the figure placed directly on the background, thus eliminating the difference in height between the figure and the background. The results of both types of tests were then compared to identify and investigate the cues that bees use to detect a structured figure, when presented over a structured background. The structure of both the figure and the background were varied in a series of experiments, training a fresh group of bees in each experiment. A randomly structured figure presented against a randomly structured background cannot be detected by the bees unless it is raised above the background. A height difference of 2 cm is sufficient to elicit a rate of landings on the figure that is significantly higher than the chance level. The detectability of the figure does not depend upon the shape of the figure or on differences in density between the structures of the figure and the background. Thus, in detecting the raised figure, the only cue used by the bees appears to be the apparent motion of the figure relative to the background. The majority of landings on a raised figure occur at its boundaries. This shows that the visual stimulus that is crucial in detecting the figure is the local discontinuity in apparent motion that occurs at the boundary. We refer to this as ‘boundary parallax ’. In a series of experiments that used a striped background and a variety of structured figures, three different types of boundary parallax were offered to the bees. These were: (i) ‘covering parallax’, at a boundary in which stripes on either side of the boundary are parallel to the boundary; (ii) ‘shearing parallax’, in which stripes on either side are perpendicular to the boundary and (iii) ‘orthogonal parallax’, in which the stripes on one side are perpendicular to those on the other side. The bees performed very well at detecting raised boundaries that offered covering or shearing parallax, despite the fact that such boundaries are not readily discernible on the basis of their static geometry. On the other hand, bees performed poorly in detecting raised boundaries that offered orthogonal parallax, despite the fact that such boundaries are geometrically quite vivid to the human eye. We propose two neural models for the detection of boundary parallax that account for the sensitivity of bees to covering and shearing parallax and their insensitivity to orthogonal parallax.

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