Quiz for Stereopsis Part 1, 2 & 3

Stereoacuity reduced

1. Wheatstone
2. Amblyscope

The intactness of Binocular Vision.

Stereoacuity is degraded

Good= 15-30 arc sec
Highly Skilled Subjects= low as 2-7 arc secs.

Stereoacuity max at fovea & diminishes exponentially w/ increasing eccentricity

TWO stereoscopic half-views, one presented to OD and other presented to OS.

Guides vergences eye movement in order to bifoveally fixate an object.

It's the smallest binocular disparity that can be detected. i.e. it is the minimum disparity beyond which no stereoscopic effect is produced.

depth tilt from interocular spatial frequency differences.

Ex: Vertical Sine Wave Low SF presented to OS and High SF presented to OD simultaneously, then the brain fuses them and we perceive a depth tilt.

monocular views for BOTH eyes are contained in the same figure as repeated patterns.

Magnitude of depth perceived depends on convergence of observer & which of the patterns are fused.

Two flat, 2D objects presented to ea. eye independently. Each image mimics the effect of having two eyed separated by IPD distance.

The complete figures viewed binocularly are called stereogram.

1. Magnocellular system
2. Operates w/Large retinal disparities & moving objects.

An illusion of depth resulting from a temporal delay of the image from one eye.

n=(PD/viewing distance sq.) x (separation bt rods)

n= angular disparity in radians

1. +/- 0.5 degrees at the fovea

2. Detects small disparities at fixation point

Stereopsis from a range of DIPLOPIC disparities(greater than Panum's Area) where DIRECTION of depth is accurately perceived but NOT mag of depth.

1. NO monocular contours

2. Require both LOCAL & GLOBAL

3. Longer time to perceive depth, but w/practice time needed deceases.

Stereomotion= a visual percept in a dynamic 3D world. The images of the left & right eyes move in horizontally opposed directions on the two retinas.

1. Two rods, ea. 1 cm diameter
2. 6 sm separation bt rods
3. One Rod fixed, one movable
4. Subject views rods through aperature.

1. Brewster(Refracting)

Qualitative

Stereoacuity reduced

4-5 arc SEC

If one converges at a position in front of a repetitive pattern, the pattern shift forward in depth to a plane near the convergence plane

Stereopsis from a range of DIPLOPIC disparities(greater than Panum's Area) where DIRECTION of depth is accurately perceived but NOT mag of depth.

1. NO monocular contours

2. Require both LOCAL & GLOBAL

3. Longer time to perceive depth, but w/practice time needed deceases.

1. Stereoacuity remains if lateral 2D retinal Image motion is < 2-3 deg/sec.

2. Microsaccades & Drifting does not degrade stereoacuity

Two flat, 2D objects presented to ea. eye independently. Each image mimics the effect of having two eyed separated by IPD distance.

The complete figures viewed binocularly are called stereogram.

1. Stereoacuity improves with practice= Perceptual learning

2. exist inVernier Acuity

3. Practice in one VF location does not transfer to other VF location

1. Line/Contour Stereograms
2. Stereogram with stimulus which is invisible monocularly but visible by disparity processing.(RANDOM DOt Stereograms= RDS)

depth tilt from interocular spatial frequency differences.

Ex: Vertical Sine Wave Low SF presented to OS and High SF presented to OD simultaneously, then the brain fuses them and we perceive a depth tilt.

The difference between the absolute disparities of two points.

Describes changes of disparity gradient over visual angle.

Testing stereoacuity at differnt locations w/in the VF.

1. Monocular Contours
2. Only require LOCAL stereopsis

1. Wheatstone
2. Amblyscope

Blue= Stereothreshold worse

The intactness of Binocular Vision.

1. Brewster(Refracting)