What is object recognition?
The ability to categorize and identify objects regardless of differences in viewing conditions.
What is the inverse projection problem?
Different objects can produce the same retinal image.
What is viewpoint invariance?
The ability to recognize an object from different viewpoints.
What is middle vision?
The stage between basic feature extraction and object recognition; involves edge detection and region grouping.
What are illusory contours?
Perceived edges without actual luminance or colour changes; the brain infers missing information.
What does Gestalt psychology state?
The whole is greater than the sum of its parts.
What are Gestalt grouping rules?
Rules describing when visual elements appear to group together.
Define good continuation.
Elements that form a continuous line or contour are grouped together.
Define similarity in Gestalt terms.
Elements similar in colour or shape tend to group together.
Define proximity.
Objects close together are grouped as part of the same object.
Define parallelism.
Parallel elements tend to be grouped together.
Define symmetry.
Symmetrical elements are perceived as belonging together.
Define common region.
Elements within a shared region are grouped, even if not close together.
Define common fate.
Elements moving together are grouped as a single object.
Define synchrony.
Elements that change or move at the same time are grouped together.
Define meaningfulness/familiarity.
Elements forming familiar or meaningful patterns are grouped together (e.g., cloud shapes).
What are perceptual committees?
Neural systems that work together like a committee to interpret visual input by consensus.
What are committee rules?
They obey physical laws and avoid interpreting accidental viewpoints.
What is an ambiguous figure?
A stimulus that can be interpreted in more than one way.
What is an accidental viewpoint?
A rare viewpoint that creates misleading regularities; committees assume such views are uncommon.
What is the Bayesian approach to perception?
A probabilistic model estimating the likelihood of a hypothesis given observed data (P(H|O)).
What is figure-ground assignment?
Determining which parts of an image are object (figure) and which are background (ground).
Which cues help in figure-ground separation?
Symmetry, size, parallelism, meaningfulness, extremal edges, relative motion, and surroundedness.
What are extremal edges?
Edges shaded to appear as if receding into depth, typically seen as figure.
