Outline: Depth Perception
Depth cues: Information in the stimulus (or observer) useful in
determining depth
Types of depth cues:
Monocular vs Binocular
Pictorial vs Motion
Physiological
Depth cue information
Specifying cue availability (e.g. J. J.
Gibson)
Describing how that information is extracted (computer vision/"Shape
from X")
Cue information quality
Ordinal
Relative
Absolute
Various kinds of depth ambiguity
Pictorial depth cues
Geometry: Image Size is proportional to
Object Size/Object Distance
Size: relative, familiar
Brightness
Occlusion
Illumination
Shading
Cast shadows
Types of cast shadows
Crater illusion, assumption of light from above
Elevation
Aerial Perspective: Farther is lower contrast and bluer
Perspective
Linear
Assumption of perpendicular/parallel
Texture
Density
Size
Foreshortening
2D contour
Other static, monocular cues
Accommodation
Blur
[Astigmatism, chromatic aberration]
Motion cues
Motion Parallax (observer moves,
environment is static), optic flow
Kinetic Depth Effect (observer is static, object rotates)
Depth ambiguity, reversal of depth sign
and rotation direction
Kinetic occlusion (texture accretion/deletion)
Binocular cues
Convergence
Stereopsis/binocular disparity
Geometry
Definition of disparity: a difference in the position of the image of
an object in the two eyes
Crossed vs uncrossed disparity
Crossed: an object's image is
more to the right in the left eye's image, hence that object is closer
to the observer than the fixation point and the eyes would need to
cross (converge) more to fixate this object
Uncrossed: an object's image is
more to the right in the right eye's image, hence that object is
farther from the observer than the fixation point and hence the eyes
would need to uncross (diverge) more to fixate this object
Matching, the correspondence problem
Random dot stereograms (Julesz)
The horopter: the locus of points with
zero disparity
Binocular fusion vs diplopia, binocular
rivalry
Stereoacuity (2'' of arc)
Stereo blindness and amblyopia (strabismic, in particular)
Types of stereo blindness vs types of cortical disparity sensitivity
Near, far, and tuned excitatory cells
The Pulfrich effect
Cue Combination as a statistical estimation problem