Effects of Head Movement and Eye Movement on Human Depth Perception from Motion Parallax

Motion parallax has been shown to be a principal cue for depth perception under monocular viewing. The simulated depth of stimuli in previous studies has been constant in both magnitude and direction. In the present study we addressed the question how the visual system detects parallactic depth change. To answer this we investigated the temporal characteristics of parallactic depth change and the effect of a motion signal on them. The stimulus consisted of four bands of 15-cycle sinusoidal gratings and parallactic depth was simulated between each band. In experiment 1, we measured the amount of perceived depth change with different frequencies (0.125 to 10 Hz) of simulated depth change and with different velocities (2.5 to 40 cm s−1) of head movements. The result showed the perceived depth change decreased with frequency of depth change, and it increased with head velocity when the frequency was constant. In experiment 2, we measured the motion threshold with different velocities of head movement. The result showed the threshold was constant across different head velocities. In experiment 3, we measured the amount of perceived depth using apparent motion stimuli with the head moving. The result showed depth decreased with SOA of apparent motion stimuli, but there was no effect of different head velocities. The results of these three experiments indicate that parallactic depth change is determined by the duration of simulated depth, which corresponds to the integration time of motion, as well as by the extent of head movement. We conclude that parallactic depth is integrated in two stages: first, integration of motion and, second, integration of motion parallax.

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Motion Parallax Driven by Head Movements: Conditions for Visual Stability, Perceived Depth, and Perceived Concomitant Motion

Perception ◽

10.1068/p5221 ◽

2005 ◽

Vol 34 (4) ◽

pp. 477-490 ◽

Cited By ~ 20

Author(s):

Hiroshi Ono ◽

Hiroyasu Ujike

Keyword(s):

Motion Perception ◽

Depth Perception ◽

Head Movement ◽

Motion Parallax ◽

Head Movements ◽

Visual Stability ◽

Movement Velocity ◽

Motion Threshold ◽

Perceived Motion

Yoking the movement of the stimulus on the screen to the movement of the head, we examined visual stability and depth perception as a function of head-movement velocity and parallax. In experiment 1, for different head velocities, observers adjusted the parallax to find (a) the depth threshold and (b) the concomitant-motion threshold. Between these thresholds, depth was seen with no perceived motion. In experiment 2, for different head velocities, observers adjusted the parallax to produce the same perceived depth. A slower head movement required a greater parallax to produce the same perceived depth as faster head movements. In experiment 3, observers reported the perceived depth for different parallax magnitudes. Perceived depth covaried with smaller parallax without motion perception, but began to decrease with larger parallax and concomitant motion was seen. Only motion was seen with the larger parallax.

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Effects of Time Delay on Depth Perception via Head-Motion Parallax in Virtual Environment Systems

Presence Teleoperators & Virtual Environments ◽

10.1162/105474600300040439 ◽

2000 ◽

Vol 9 (6) ◽

pp. 638-647 ◽

Cited By ~ 3

Author(s):

Hanfeng Yuan ◽

W. L. Sachtler ◽

Nat Durlach ◽

Barbara Shinn-Cunningham

Keyword(s):

Time Delay ◽

Virtual Environment ◽

Depth Perception ◽

Head Movement ◽

Time Delays ◽

Motion Parallax ◽

Head Motion ◽

Depth Cues ◽

Random Dot Patterns

Experiments were conducted to determine how the ability to detect and discriminate head-motion parallax depth cues is degraded by time delays between head movement and image update. The stimuli consisted of random-dot patterns that were programmed to appear as one cycle of a sinusoi dal grating when the subject's head moved. The results show that time delay between head movement and image update has essentially no effect on the ability to discrimi nate between two such gratings with different depth char acteristics when the delay is less than or equal to roughly 265 ms.

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Depth Perception in Driving: Alcohol Intoxication, Eye Movement Changes, and the Disruption of Motion Parallax

10.17077/drivingassessment.1012 ◽

2001 ◽

Author(s):

Mark Nawrot

Keyword(s):

Eye Movement ◽

Depth Perception ◽

Alcohol Intoxication ◽

Motion Parallax

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User Behavior and the Importance of Stereo for Depth Perception in Fish Tank Virtual Reality

Presence Teleoperators & Virtual Environments ◽

10.1162/pres_a_00327 ◽

2020 ◽

Vol 27 (2) ◽

pp. 206-225 ◽

Cited By ~ 1

Author(s):

Sirisilp Kongsilp ◽

Matthew N. Dailey

Keyword(s):

Virtual Reality ◽

Depth Perception ◽

Head Movement ◽

User Behavior ◽

Motion Parallax ◽

Psychological Research ◽

Human Vision ◽

Fish Tank ◽

Experimental Findings

Since one of the most important aspects of a Fish Tank Virtual Reality (FTVR) system is how well it provides the illusion of depth to users, we present a study that evaluates users' depth perception in FTVR systems using three tasks. The tasks are based on psychological research on human vision and depth judgments common in VR applications. We find that participants do not perform well under motion parallax cues only, when compared with stereo only or a combination of both kinds of cues. Measurements of participants' head movement during each task prove valuable in explaining the experimental findings. We conclude that FTVR users rely on stereopsis for depth perception in FTVR environments more than they do on motion parallax, especially for tasks requiring depth acuity.

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Evaluation of Linear Blending between view images and Depth Perception by Monocular Motion Parallax in Visually Equivalent Light Field 3D display

Proceedings of the International Display Workshops ◽

10.36463/idw.2020.0507 ◽

2020 ◽

pp. 507

Author(s):

Ren Kamada ◽

Haruki Mizushina ◽

Munekazu Date ◽

Shinya Shimizu ◽

Susumu Yamamoto ◽

...

Keyword(s):

Depth Perception ◽

Light Field ◽

Motion Parallax ◽

3D Display

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Rapid horizontal gaze movement in the monkey

Journal of Neurophysiology ◽

10.1152/jn.1995.73.4.1632 ◽

1995 ◽

Vol 73 (4) ◽

pp. 1632-1652 ◽

Cited By ~ 85

Author(s):

J. O. Phillips ◽

L. Ling ◽

A. F. Fuchs ◽

C. Siebold ◽

J. J. Plorde

Keyword(s):

Eye Movement ◽

Head Movement ◽

Vertical Axis ◽

Head Position ◽

Head Movements ◽

Gaze Shifts ◽

Gaze Shift ◽

The Gaze ◽

Small Correction ◽

Horizontal Gaze

1. We studied horizontal eye and head movements in three monkeys that were trained to direct their gaze (eye position in space) toward jumping targets while their heads were both fixed and free to rotate about a vertical axis. We considered all gaze movements that traveled > or = 80% of the distance to the new visual target. 2. The relative contributions and metrics of eye and head movements to the gaze shift varied considerably from animal to animal and even within animals. Head movements could be initiated early or late and could be large or small. The eye movements of some monkeys showed a consistent decrease in velocity as the head accelerated, whereas others did not. Although all gaze shifts were hypometric, they were more hypometric in some monkeys than in others. Nevertheless, certain features of the gaze shift were identifiable in all monkeys. To identify those we analyzed gaze, eye in head position, and head position, and their velocities at three points in time during the gaze shift: 1) when the eye had completed its initial rotation toward the target, 2) when the initial gaze shift had landed, and 3) when the head movement was finished. 3. For small gaze shifts (< 20 degrees) the initial gaze movement consisted entirely of an eye movement because the head did not move. As gaze shifts became larger, the eye movement contribution saturated at approximately 30 degrees and the head movement contributed increasingly to the initial gaze movement. For the largest gaze shifts, the eye usually began counterrolling or remained stable in the orbit before gaze landed. During the interval between eye and gaze end, the head alone carried gaze to completion. Finally, when the head movement landed, it was almost aimed at the target and the eye had returned to within 10 +/- 7 degrees, mean +/- SD, of straight ahead. Between the end of the gaze shift and the end of the head movement, gaze remained stable in space or a small correction saccade occurred. 4. Gaze movements < 20 degrees landed accurately on target whether the head was fixed or free. For larger target movements, both head-free and head-fixed gaze shifts became increasingly hypometric. Head-free gaze shifts were more accurate, on average, but also more variable. This suggests that gaze is controlled in a different way with the head free. For target amplitudes < 60 degrees, head position was hypometric but the error was rather constant at approximately 10 degrees.(ABSTRACT TRUNCATED AT 400 WORDS)

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