Stroboscopic Motion in Depth

Perception ◽  
1982 ◽  
Vol 11 (6) ◽  
pp. 733-741 ◽  
Author(s):  
David Finlay

Temporal limits of stroboscopic apparent motion in depth have been examined. For monocular viewing the limits are similar to those obtained for motion in the frontal plane, while those for binocular viewing are greatly narrowed. In another experiment the contraction in space over which apparent movement occurs was measured. The results are discussed in terms of a filter representation proposed by Caelli and Finlay.

2018 ◽  
pp. 186-199

Background Coincidence-anticipation timing (CAT) responses require individuals to determine the time at which an approaching object will arrive at (time to collision) or pass by (time to passage) the observer and to then make a response coincident with this time. Previous studies suggest that under some conditions time to collision estimates are more accurate when binocular and monocular cues are combined. The purpose of this study was to compare binocular and monocular coincidence anticipation timing responses with the Bassin Anticipation Timer, a device for testing and training CAT responses. Methods: Useable data were obtained from 20 participants. Coincidence-anticipation timing responses were determined using a Bassin Anticipation Timer over a range of approaching stimulus linear velocities of 5 to 40mph. Participants stood to the left side of the Bassin Anticipation track. The track was below eye height. The participants’ task was to push a button to coincide with arrival of the approaching stimulus at a location immediately adjacent to the participant. CAT responses were made under three randomized conditions: binocular viewing, monocular dominant eye viewing, and monocular non-dominant eye viewing. Results: Signed (constant), unsigned (absolute), and variable (standard deviation) CAT response errors were determined and compared across viewing conditions at each stimulus velocity. There were no significant differences in CAT errors between the conditions at any stimulus velocity, although the differences in signed and unsigned errors approached significance at 40mph. Conclusions: The addition of binocular cues did not result in a reduction in coincidence anticipation timing response errors compared to the monocular viewing conditions. There were no differences in CAT response errors between the monocular dominant eye viewing and monocular non-dominant eye viewing conditions.


Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 371-371
Author(s):  
R M Steinman ◽  
T I Forofonova ◽  
J Epelboim ◽  
M R Stepanov

Epelboim et al (1996 Vision Research35 3401 – 3422) reported that cyclopean gaze errors were smaller than either eye's during tapping and looking-only tasks. This raised two questions: (i) does cyclopean gaze accuracy require binocular input, and (ii) when only one eye sees, is its gaze more accurate than the patched eye's? Most oculomotorists probably expect an affirmative answer to both. Neither expectation was fulfilled. The Maryland Revolving Field Monitor recorded, with exceptional accuracy, eye movements of two unrestrained subjects tapping or only looking, in a specified order, at four randomly positioned LEDs, with monocular or binocular viewing. Subjects either tapped with their finger tips naturally, or unnaturally via a rod (2 mm diameter, 1.5 cm long), glued to a sewing thimble. Instructions were to be fast, but make no order errors. With binocular viewing, cyclopean gaze accuracy was best during looking-only. During natural tapping, gaze errors increased, becoming no smaller than success required. Both tasks were learned equally fast, but as expected, the younger subject (aged 27 years) performed ∼ 40% faster than the older subject (aged 69 years). Unnatural, monocular viewing produced odd results, eg cyclopean gaze error was smallest when only one eye could see in some conditions. Only the older subject served in the unnatural tapping task because the younger's errors were too close to his gaze control limit. The older subject, who was suitable, reduced his cyclopean gaze error by 56%, from 1.4 to 0.9 deg. These results support our claim that the gaze error allowed is adjusted to the visuomotor demands of different tasks.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arvind Chandna ◽  
Jeremy Badler ◽  
Devashish Singh ◽  
Scott Watamaniuk ◽  
Stephen Heinen

AbstractTo clearly view approaching objects, the eyes rotate inward (vergence), and the intraocular lenses focus (accommodation). Current ocular control models assume both eyes are driven by unitary vergence and unitary accommodation commands that causally interact. The models typically describe discrete gaze shifts to non-accommodative targets performed under laboratory conditions. We probe these unitary signals using a physical stimulus moving in depth on the midline while recording vergence and accommodation simultaneously from both eyes in normal observers. Using monocular viewing, retinal disparity is removed, leaving only monocular cues for interpreting the object’s motion in depth. The viewing eye always followed the target’s motion. However, the occluded eye did not follow the target, and surprisingly, rotated out of phase with it. In contrast, accommodation in both eyes was synchronized with the target under monocular viewing. The results challenge existing unitary vergence command theories, and causal accommodation-vergence linkage.


Perception ◽  
1979 ◽  
Vol 8 (4) ◽  
pp. 389-396 ◽  
Author(s):  
Donald E Mitchell ◽  
Martin Kaye ◽  
Brian Timney

A behavioural method is described for the assessment of depth perception of kittens. Measurement is made of the smallest separation in depth that can be discriminated between two adjacent stimuli under both monocular and binocular viewing conditions. Normal animals can discriminate much smaller separations in depth when using two eyes than with monocular viewing, implying the presence of a cue to depth that is uniquely available with binocular viewing. The test provides a quick and reliable way of screening animals for stereopsis.


1995 ◽  
Vol 80 (3_suppl) ◽  
pp. 1069-1070 ◽  
Author(s):  
Yutaka Shimizu

Using an apparent-motion mode, the psychophysical effect of apparent movement was introduced for tactile letter reading. This mode reduces time for the tracing mode. Five temporal parameters were examined for application to actual communication. 4 subjects recognized words composed of 3 to 7 Japanese letters in about 5 seconds.


Author(s):  
R. E. Wienke ◽  
W. C. Steedman

The ability to detect small excursions of apparent movement of a point light source was investigated. Apparent movement was achieved by alternately presenting a point source in two different planes. The presentations, each lasting about 500 milliseconds, had an overlap of approximately 8 milliseconds. Using 7 subjects, the limen for apparent motion was a stimulus separation of 43.9 mm, which is a visual angle of 1′ 21″. Possible application of the effect in a highly precise visual guidance system is discussed in light of the results.


2020 ◽  
Author(s):  
Jenna Cao ◽  
Nickolas F. Goenadi ◽  
Emma L. Neto ◽  
Isabel R. Shapiro

The present study aimed to determine whether stimulus location (central or peripheral) or eye viewing condition (binocular, dominant monocular, or non-dominant monocular) had a greater magnitude of effect on perception of the sound-induced flash illusion (SIFI). Both the fission illusion (when one flash paired with two beeps is perceived as two flashes) and the fusion illusion (when two flashes paired with one beep are perceived as one flash) were measured in all location and eye viewing conditions. Analyses revealed significant fission and fusion illusions in all conditions. Additionally, we found significant differences in central and peripheral criterion levels that were driven by differences between binocular and monocular viewing conditions. Data analyses demonstrated that location of the visual stimulus had a greater magnitude of effect on the illusion than eye viewing condition. Our findings add to the growing literature supporting the mechanisms underlying central-peripheral eccentricity, and contradict the optimal integration model of the SIFI. The implications of these results would help better our understanding of the SIFI and audiovisual integration. Future studies must be conducted to confirm these results in a more representative sample.


2006 ◽  
Vol 403 (1-2) ◽  
pp. 40-45 ◽  
Author(s):  
Chia-Yen Yang ◽  
Jen-Chuen Hsieh ◽  
Yin Chang

Perception ◽  
1982 ◽  
Vol 11 (2) ◽  
pp. 187-199 ◽  
Author(s):  
Walter C Gogel ◽  
Bernard W Griffin

Induced motion is not limited to continuous motions presented on a frontoparallel plane. Experiments were conducted to investigate several varieties of induced motion to which theories of induced motion must apply. The observer indicated the perceived path of motion of a vertically moving test point to which induced motion at right angles to the physical motion was added by the motion of two inducing points. In experiment 1 all motions (both apparently and physically) were in a frontoparallel plane. It was found that discrete displacement as well as continuous motion of the test and inducing points produced substantial amounts of induction. In experiment 2 the inducing points were continuously moved in stereoscopic distance rather than remaining in an apparent frontoparallel plane. A large amount of apparent motion in depth was found in the vertically moving test point and was interpreted as an induced motion in depth. In experiment 3 an alternative interpretation of the phenomenon of experiment 2, in terms of an apparent vergence for the two images of the test point, was investigated and found to be unlikely. In experiment 4, with all the points moving continuously in a frontoparallel plane, eye motions as well as induced motions were measured, with the observer fixating either the test point or an inducing point. Substantial amounts of induction were obtained under both conditions of fixation. The consequences of these findings for theories of induced motion are discussed.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tobias Wibble ◽  
Tony Pansell

Abstract Vertical vergence is generally associated with one of three mechanisms: vestibular activation during a head tilt, induced by vertical visual disparity, or as a by-product of ocular torsion. However, vertical vergence can also be induced by seemingly unrelated visual conditions, such as optokinetic rotations. This study aims to investigate the effect of vision on this latter form of vertical vergence. Eight subjects (4m/4f) viewed a visual scene in head erect position in two different viewing conditions (monocular and binocular). The scene, containing white lines angled at 45° against a black background, was projected at an eye-screen distance of 2 m, and rotated 28° at an acceleration of 56°/s2. Eye movements were recorded using a Chronos Eye-Tracker, and eye occlusions were carried out by placing an infrared-translucent cover in front of the left eye during monocular viewing. Results revealed vergence amplitudes during binocular viewing to be significantly lower than those seen for monocular conditions (p = 0.003), while torsion remained unaffected. This indicates that vertical vergence to optokinetic stimulation, though visually induced, is visually suppressed during binocular viewing. Considering that vertical vergence is generally viewed as a vestibular signal, the findings may reflect a visually induced activation of a vestibular pathway.


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