Binocular Depth Perception Flashcards
What is depth perception?
The visual judgment, in the “Z” dimension of space, of the distance between objects or surfaces, expressed in “relative” terms of measurement.
For SILO, adding BO makes the target appear _______.
smaller
For SOLI, BO makes the target appear __________.
larger
What determines binocular parallax?
Absolute depth
What is the binocular parallax?
vergence angle of an object if looking directly at it
What is absolute disparity?
The difference between the binocular parallax of an object and the convergence angle of the eyes.
What gives the stimulus for fusional vergence?
absolute disparity
What is the visual sensitivity to absolute disparity?
Not very good. 6 minutes of arc
What happens if absolute disparity is less than 6 minutes of arc?
Will not stimulate vergence movement
What is the stimulus for stereopsis?
The difference between the absolute horizontal disparities of two points.
the relative disparity between two points in REAL space is ____________ proportional to the SQUARE of the distance from the observer.
inverseley
Why dont small movements of the eyes result in depth changes?
They are applied to all objects in the visual field
What is depth constancy?
perception that the depth within a familiar object (or the distance between two objects) is unchanged despite the change in binocular disparity that occurs when the viewing distance changes.
When do absolute and relative vertical disparities exist?
1) When an object is nearer to one eye than to the other
2) When the observer is experiencing the induced effect of aniseikonia
What are vertical disparities used for?
used to scale perceived depth and size of stereoscopic surfaces
Equation for disparity gradient
disparity / separation
Horizontal disparity gradient for objects on the horopter
0 disparity gradient
The horizontal disparity for objects inside the horopter
infinite
the target is independently presented to one eye.
Stereoscopic half-view
two stereoscopic half-views, one of which is presented to the right eye and one to the left eye.
Stereo pair
the complete figure formed by binocularly viewing a stereo pair.
Stereogram
an instrument that alters the relationship between distance and disparity by means of lenses, mirrors, or prisms so that an independent image can be presented to each eye.
stereoscope
disparity in a stereogram is _______ proportional (linear) to the target distance
inversely
What kind of glasses do vectograms (titmus test) use?
anaglyph glasses
