Topic 5: Object Perception Flashcards
Object Recognition
the ability to identify objects
Inverse Projection Problem
the idea that a particular image on the retina could have been caused by an infinite number of different objects
this means that the retinal image does not unambiguously specify a stimulus
Viewpoint Invariance
the condition in which object properties don’t change when viewed from different angles
responsible for our ability to recognize objects when viewed from different angles
Perceptual Organization
the process by which small elements become perceptually grouped into larger objects
Grouping
in perceptual organization, the process by which visual events are “put together” into units or objects
Segregation
the process of separating one area or object from another
Gestalt Psychologists
an approach to psychology that developed as a reaction to structuralism
the Gestalt approach proposes principles of perceptual organization and figure-ground segregation and states that “the whole is different than the sum of its parts”
Structuralism
the approach to psychology, prominent in the late 19th and early 20th centuries, that postulated that perceptions result from the summation of many elementary sensations
the Gestalt approach to perception was, in part, a reaction to structuralism
Apparent Movement
an illusion of movement that occurs when two objects separated in space are presented rapidly, one after another, separated by a brief time interval
Illusory Contours
contour that is perceived even though it is not present in the physical stimulus
Principles of Perceptual Organization
principles describe how elements in a scene become grouped together
many of these principles were originally proposed by the Gestalt psychologists, but new principles have also been proposed by recent researchers
Principle of Good Continuation
points that, when connected, result in straight or smoothly curving lines are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path
Pragnaz
a Gestalt principle of perceptual organization that states that every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
also called the principle of good figure or the principle of simplicity
Principle of Similarity
similar things appear to be grouped together
Principle of Proximity
things that are near each other appear to be grouped together
Principle of Common Fate
things that are moving in the same direction appear to be grouped together
Principle of Common Region
elements that are within the same region of space appear to be grouped together
Principle of Uniform Connectedness
a connected region of the same visual properties, such as lightness, color, texture, or motion, is perceived as a single unit
Figure-Ground Segregation
the perceptual separation of an object from its background
Figure
when an object is seen as separate from the background (the “ground”), it is called a figure
Ground
in object perception, the background is called the ground
Reversible Figure-Ground
a figure-ground pattern that perceptually reverses as it is viewed, so that the figure becomes the ground and the ground becomes the figire
the best known reversible figure-ground pattern is Rubin’s vase-face pattern
Border Ownership
when two areas share a border, as occurs in figure-ground displays, the border is usually perceived as belonging to the figure
Figural Cues
visual cues that determine how an image is segregated into figure and ground
Recognition By Components (RBC) Theory
theory that states that objects are comprised of individual geometric components called geons, and we recognize objects based on the arrangements of those geons
Geons
according to recognition by components (RBC) theory, individual geometric components that comprise objects
Scene
a view of a real-world environment that contains (a) background elements and (b) multiple objects that are organized in a meaningful way relative to each other and the background
Gist of a Scene
general description of a scene
people can identify most scenes after viewing them for only a fraction of a second, as when they flip rapidly from one TV channel to another
it takes longer to identify the details within a scene
Persistence of Vision
a phenomenon in which perception of any stimulus persists for about 250 ms after the stimulus is physically terminated
Visual Masking Stimulus
a visual pattern that, when presented immediately after a visual stimulus, decreases a person’s ability to perceive the stimulus
this stops the persistence of vision and therefore limits the effective duration of the stimulus
Global Image Features
information that may enable observers to rapidly perceive the gist of a scene
features associated with specific types of scenes include degree of naturalness, degree of openness, degree of roughness, degree of expansion, and color
Regularities of the Environment
characteristics of the environment that occur regularly and in many different situations
Physical Regularities
regularly occurring physical properties of the environment
for example, there are more vertical than horizontal orientations in the environment than oblique (angled) orientations
Light-From-Above Assumption
the assumption that light usually comes from above, which influences our perception of form in some situations
Semantic Assumptions
characteristics associated with the functions associated with different types of scenes
these characteristics are learned from experience
for example, most people are aware of the kinds of activities and objects that are usually associated with kitchens
Scene Schema
an observer’s knowledge about what is contained in typical scenes
an observer’s attention by knowledge of what is usually found in the scene
Likelihood Principle
the idea proposed by Helmholtz that we perceive the object that is most likely to have caused the pattern of stimuli we have received
Unconscious Principle
the idea proposed by Helmholtz that some of our perceptions are the result of unconscious assumptions that we make about the environment
Bayesian Influence
a statistical approach to perception in which perception is determined by taking probabilities into account
these probabilities are based on past experiences in perceiving properties of objects and scenes
Prior Probability
in Bayesian influence, a person’s initial estimate of the probability of an outcome
Likelihood
in Bayesian influence, the extent to which the available evidence is consistent with a particular outcome
