Chapter 6 Flashcards
Monocular depth cues
Cues that are based on the retinal image and that provide information about depth even with only one eye open
Oculomotor depth cues
Cues that are based on feedback from the oculomotor muscles controlling the shape of the lens and the position of the eyes
Static monocular depth cues
Cues that provide information about depth on the basis of the position of objects in the retinal image, the size of the retinal image, and the effects of lighting in the retinal image.
Partial occlusion
A position-based depth cue-in scenes whee one object partially hides (occludes) another object, the occlusion indicates that the former is closer than the latter
Relative height
A position-based depth cue-the relative height of the objects in the retinal with respect to eye level if there is no visible horizon-provides information about the objects relative distance from the observer
Size-distance relation
The farther away an object is from the observer, the smaller is its retinal image
Visual angle
The angle subtending by an object in the field of view
Size perspective
A depth cue in scenes in which the size-distance relation is apparent
Familiar size
A size-based depth cue-knowing the retinal image size of a familiar object at a familiar distance lets us use its retinal image size to gauge its distance
Relative size
A size based depth cue-under the assumption that two or more object are about the same size, the relative size of their retinal images can be used to judge their relative distances
Texture gradient
A size-based depth cue-if surface variations or repeated elements of a surface are fairly regular in size and spacing, the retinal image size of these equal-size features decreased as their distance increases
Linear perspective
A size-based depth cue- parallel lines appear to converge as they recede in depth
Linear Perspective
A size-based depth cue parallel lines appear to converge as they recede in depth
Atmospheric perspective
A lighting-based depth cue the farther away an object is, the more air the light must pass through to reach us and the more that light can be scattered, with the result that distant objects appear less distinct than nearby objects
Motion parallax
A dynamic depth cue-the difference in speed and direction with which objects appear to move in the retinal image as an observer moves within the scene.
Optic flow
A dynamic depth cue-the relative motions of objects and surfaces I. The retinal image as the observer moves forward and backward through a scene
Deletion
A dynamic depth cue-the gradual hiding of an object as it passes behind another one
Accretion
A dynamic depth cue-the gradual revealing of an object as it emerges from behind another one
Stereopsis
The vivid sense of depth arising from the visual systems processing of the different retinal images in the two eyes.
Binocular disparity
A depth cue based on differences in relative positions of the retinal images of objects in the two eyes
Corresponding points
A point on the left retina and a point on the right retina that would coincide if the two retinas were superimposed-for example, the fovea of the two eyes
Noncorresponding points
A point on the left retina and a point on the right retina that wouldn’t coincide if the two retinas were superimposed-for example, the fovea of one eye and a point 4mm to the right of the fovea in the other eye
Horopter
An imaginary surface defined by the locations in s scene from which objects would project retinal images at corresponding points
Crossed disparity
A type of binocular disparity produced by an object that is closer than the horopter-you would have to cross your eyes to look at it
Uncrossed disparity
A type of binocular disparity produced by an object that is farther away than the horopter-you would have to uncross your eyes to look at it
Zero disparity
A type of binocular disparity in which the retinal image of an object falls at corresponding points in the two eyes
Correspondence problem
The problem of determining which features in the retinal image in one eye correspond to which features in the retinal image in the other eye
Stereogram
Two depictions of a scene that differ in the same way as an observers two retinal images of that scene do; an observer who simultaneously views one image with one eye and the other image with the one eye and the other image with the other eye (as in a stereoscope) will see a combined image in depth
Anaglyph
A stereo gram in which the two photographs taken from adjacent camera positions are printed in contrasting colors and then superimposed; an observer who views an anaglyph with special glasses in which one lens filters out one of the other colors and the other lens filters out the other color will see a single image in depth
Binocular cells
Neurons that respond best to the stimulation of their receptive fields in both eyes simultaneously
Eemmert’s law
Size-distance invariance of retinal afterimages-the perceived size of an afterimage is proportional to the distance of the surface on which its projected
Shape constancy
A type of perceptual constancy-the tendency to perceive an objects shape as constant despite changes in the shape of the objects retinal image due to the objects changing orientation
Shape-slant invariance
The relation between perceived shape and perceived slant: the perceived shape of an object depends on its perceived slant, and vise versa
Ames room
A room specially designed to create an illusory perception of depth; when viewed with one eye through a peephole, all of the rooms trapezoidal surfaces look rectangular
