chapter 5 (beginning) Flashcards
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
one of the reasons why it is difficult to design a perceiving machine
why is it difficult to design a perceiving machine
- inverse projection problem
- objects can be hidden or blurred
- objects look different from different viewpoints
viewpoint invariance
the ability to recognize an object seen from different viewpoints
perceptual organization
the process by which small elements in our visual field become perceptually grouped and segregated to create a scene/perception
what are the two components of perceptual organization
grouping and segregation
grouping
the process by which elements in a visual scene are “put together” into coherent units or objects
segregation
the process of separating one area or object from another
structuralism
a precursor to gestalt psychology - prompted a reaction
idea that perceptions come from the summation of many elementary sensations - gestalt psychologists rejected this
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
provides support for gestalt psychology:
- because apparent movement cannot be created just by sensations along - there is nothing between the objects/images
- so the perceptual system must create the perception of movement where there actually is none
illusory contours
contour that is perceived even though it is not present in the physical stimulus - think: pac man triangle
principles of perceptual organization
principles that describe how elements of a scene become grouped together - started by gestalt psychologists, but carried on by recent researchers
principle of good continuation
we perceive overlapping or partially covered lines as following smooth paths
principle of pragnanz
also good figure or simplicity
- every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
similarity
similar things appear to be grouped together - auditory stimuli as well as visual
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 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
when we see a separate object, it is usually seen as a figure that stands out from its background, which is called the ground
the figure tends to be more “thinglike” than the ground and is usually seen as being in front of the ground
nears the borders it shares with the figure the ground is comparitvely unformed
reversible figure ground
a pattern that perceptually reverses so that the figure and the ground are interchangeable
border ownership
a property of figure ground segregation where the border separating the figure from the ground appears to belong to the figure
figural cues - 2 examples
visual cues that determine how an image is segregated into figure and ground
ex.
1. areas lower in the field of view are more likely to be perceived as figure
- figures are more likely to be perceived on the convex side of borders (borders that bulge outwards)
gestalt psychologists and experience
built in principles tend to overried past experience in perception
- W M example
- look like a W and M when they overlap, but weird shape when they are stacked
meaninfulness
critique of gestalt psychologists’ views on experience
figure ground with sillouette of a woman - shows that formation can be affected by the meaningfulness of a stimulus
recognition by components theory
theory that states that objects are comprised of individual geometric components called geons, and that we recognize objects based on the arrangement of those geons
how many geons does RBC theory identify
36
how does RBC theory account for viewpoint invariance?
geons can be recognized from any viewpoint
what doesn’t RBC theory account for?
- grouping or organization
- objects that typically don’t have geometric components
-distinguishing between objects within a given category
scene
a view a real world environment that contains background elements and multiple objects that a 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
mary potter: asked observers to identify a target picture within 16 rapidly presented pictures - could do this with almost 100% accuracy even when the pictures were only presented for a 1/4 of a second - nearly as accurate when the target picture was only specified by a written description
scenes vs objects
scenes: extended in space and are acted within
objects: compact and acted upon
