Object Recognition Flashcards
(12 cards)
The process of object recognition according to Biederman (1987)
- The visual system detects edges and boundries
- Detection of non-accidental properties, to determine Geon shape
- Detection of regions of concavity, to determine Geon segregation
- Combination of information from step 2, to determine which Geons make the object.
- Compares the identified arrangement of Geons to stored object representations in memory.
How does Beiderman (1987) support Geon Theory
Recognition was impaired when edge information at points of concavity is removed
Viewpoint dependent mechanisms for?
Complex within category decisions
Viewpoint invariance mechanisms for?
Easy categorical decisions
Viewpoint Invariance Theories
Assume the ease of object recognition is not affected by an observers viewpoint (e.g. Biederman, 1987)
Viewpoint Dependant Theories
Assume changes in viewpoint reduce the speed and accuracy of object recognition.
Stage Model of Object Recognition
Object recognition proceeds through a series of distinct, sequential processing stages.
Cascade Model of Object Recognition
Object recognition involves overlapping processes that operate continuously and in parallel.
Apperceptive Agnosia
Problems with early processing (shape extraction)
Apperceptive Agnosia Explained
Affects visual representations directly, difficulties in putting components together to create a good structural description of an object. Effects can be graded, some include difficulties recognising any object while others effect unusual views of objects.
Associative Agnosia
Problems with later processing (recognition)
Associative Agnosia Explained
Visual representations are intact, its possible to create structural representations BUT this cannot be matched to what is stored in memory. Results in difficulties recognising objects.
