Chapter 10 PSYCH 225 (234-242)

Disparity Turning Curve

This curve indicates the neural responses that occurs when stimuli presented to the left and right eyes create different amounts of disparity

Stereoscope

A device introduced by Charles Wheatstone, which produces a convincing illusion of depth by using two slightly different pictures

Binocular depth cells or disparity selective cells

A given cell responds best when stimuli presented to the left and right eyes create a specific amount of absolute disparity

Active Method

Alternates the left eye and right eye images on the screen 30 or more times a second, this has this name because the glasses have a shutter system that is synchronized with the alternation of images occurring on the TV screen

2-D Movies

Any depth perceived in these movies results from monocular or pictorial depth cues

Neurons that respond to absolute disparity?

Binocular depth cells Disparity selective cells

What are the ways to separate left and right images?

Color one image red and the other green and to view the film through glasses with a red filter for one eye and a green filter for the other eye. Another way is to create the left and right images from polarized light one image being polarized so the image is vertical and the other image so the image is horizontal

Stereoscopic Depth Perception

Depth perception created by input from both eyes

Absolute disparity indicates?

Distance from the horopter

Correspondence Problem

How does the visual system match the parts of the images in the left and right eyes that correspond to each other

Neurons sensitive to relative disparity are found?

In the temporal lobe

Polarized light

Light waves that vibrate in only one orientation. (creates better color than the red-green method)

Another technique used to demonstrate a link between neural activity and depth perception?

Microstimulation a procedure in which a small electrode is inserted into the corte and an electrical charge is passed through the electrode to activate the neurons near the electrode

Strabismus

Misalignment of the eyes, when this occurs, the visual system suppresses vision in one of the eyes to avoid double vision

Horopter

Objects that fall on corresponding points are located on this surface

How does the visual system match up the images in the two eyes?

On the basis of the specific features of the objects

Corresponding retinal points

Points on the retina that overlap if the eyes are superimposed on each other. To determine them, imagine tat the left eye is slid on top of the right eye

Relative Disparity is related to objects?

Positions related to each other

Neuron sensitive to absolute disparity are found?

Primary visual receiving area

Random Dot Stereogram

Showed that observers can perceive depth in displays that contain no depth information other than disparity

Disparity selective neurons are responsible for?

Stereopsis

Disparity creates?

Stereopsis Disparity focuses on geometry not perception

Angle of disparity

The amount of absolute disparity

Absolute Disparity

The degree to which these objects deviate from falling on corresponding points

Relative Disparity

The difference in absolute disparities of objects in a scene, helps indicate where in a scene are located relative to one another

Binocular Disparity

The differences in the images on the left and right retinas

Noncorresponding Points

The images of objects that are not on the horopter

Stereopsis

The relationship between disparity and what observers perceive, The impression of depth that results from information provided by binocular disparity

Lenticular Projection

The screen is coated with a film that contains two sets of lenses that direct different images to the left and right eyes

Stereoscopic Vision

Two-eyed depth perception, involves mechanisms that take into account differences in the images formed on the left and right eyes

Passive Method

Works with two superimposed polarized images viewed through polarizing glasses