Tirin Moore, Robert J. Schafer, and Behrad Noudoost
- Published in print:
- 2010
- Published Online:
- February 2010
- ISBN:
- 9780195326598
- eISBN:
- 9780199864904
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195326598.003.0012
- Subject:
- Psychology, Neuropsychology, Evolutionary Psychology
Primate vision is severely constrained by the fact that fine details in a visual scene can only be resolved by the fovea, where acuity is greatest. This tiny portion of each retina, which amounts to ...
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Primate vision is severely constrained by the fact that fine details in a visual scene can only be resolved by the fovea, where acuity is greatest. This tiny portion of each retina, which amounts to less than half of 1 degree of visual angle, must be moved around and positioned on behaviorally relevant stimuli in order to facilitate visual perception. Saccadic eye movements (saccades) reposition the direction of gaze (and the fovea) some three to five times per second and provide the means by which detailed visual information is accumulated during visual scanning. The ability to move the eyes accurately and precisely among targets of interest is crucial to adaptive behavior. This chapter shows that the neural mechanisms involved in mobilizing the fovea and the focus of attention together are also involved in moving attention by itself.Less
Primate vision is severely constrained by the fact that fine details in a visual scene can only be resolved by the fovea, where acuity is greatest. This tiny portion of each retina, which amounts to less than half of 1 degree of visual angle, must be moved around and positioned on behaviorally relevant stimuli in order to facilitate visual perception. Saccadic eye movements (saccades) reposition the direction of gaze (and the fovea) some three to five times per second and provide the means by which detailed visual information is accumulated during visual scanning. The ability to move the eyes accurately and precisely among targets of interest is crucial to adaptive behavior. This chapter shows that the neural mechanisms involved in mobilizing the fovea and the focus of attention together are also involved in moving attention by itself.
Sebastian Schneegans, John P. Spencer, and Gregor Schöner
- Published in print:
- 2015
- Published Online:
- January 2016
- ISBN:
- 9780199300563
- eISBN:
- 9780190299026
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199300563.003.0008
- Subject:
- Neuroscience, Development
This chapter presents a model of working memory and change detection in visual scenes that addresses the binding problem: When memorizing a group of objects, each with a location and multiple surface ...
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This chapter presents a model of working memory and change detection in visual scenes that addresses the binding problem: When memorizing a group of objects, each with a location and multiple surface features, how are the properties of each individual object bound together and kept separate from the properties of other objects? In the proposed architecture a stack of feature maps forms the neural substrate for scene working memory. Binding makes use of a spatial dimension shared by all feature maps. The operations of attentional selection and space-feature integration act jointly to memorize multiple objects in a bound fashion and detect changes in visual scenes. The need for attentional selection in some task implies sequential processing of individual items, whereas in other tasks, items can be processed in parallel. This aspect of the model’s behavior provides qualitative predictions about human performance.Less
This chapter presents a model of working memory and change detection in visual scenes that addresses the binding problem: When memorizing a group of objects, each with a location and multiple surface features, how are the properties of each individual object bound together and kept separate from the properties of other objects? In the proposed architecture a stack of feature maps forms the neural substrate for scene working memory. Binding makes use of a spatial dimension shared by all feature maps. The operations of attentional selection and space-feature integration act jointly to memorize multiple objects in a bound fashion and detect changes in visual scenes. The need for attentional selection in some task implies sequential processing of individual items, whereas in other tasks, items can be processed in parallel. This aspect of the model’s behavior provides qualitative predictions about human performance.
Laurence T. Maloney
- Published in print:
- 2003
- Published Online:
- March 2012
- ISBN:
- 9780198505006
- eISBN:
- 9780191686764
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198505006.003.0009
- Subject:
- Psychology, Vision
This chapter demonstrates that human surface colour perception can be modelled as algorithms that, over certain ranges of environmental conditions, manage to assign colours to objects that are in ...
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This chapter demonstrates that human surface colour perception can be modelled as algorithms that, over certain ranges of environmental conditions, manage to assign colours to objects that are in correspondence with specific, objective properties of the object's surface, called intrinsic colours. The chapter suggests that under certain circumstances, human observers do seem to estimate intrinsic surface colours accurately. Environmental constraints permit us to succeed in perceiving stable surface colours. These constraints can be thought of as a list of precise assertions concerning a visual scene. If all of the assertions on the list are true of the scene, then human colour vision, confined to a specified environment, will assign colours to surfaces in that scene that are the same as those it assigns to these surfaces in another scene that also satisfies these assertions.Less
This chapter demonstrates that human surface colour perception can be modelled as algorithms that, over certain ranges of environmental conditions, manage to assign colours to objects that are in correspondence with specific, objective properties of the object's surface, called intrinsic colours. The chapter suggests that under certain circumstances, human observers do seem to estimate intrinsic surface colours accurately. Environmental constraints permit us to succeed in perceiving stable surface colours. These constraints can be thought of as a list of precise assertions concerning a visual scene. If all of the assertions on the list are true of the scene, then human colour vision, confined to a specified environment, will assign colours to surfaces in that scene that are the same as those it assigns to these surfaces in another scene that also satisfies these assertions.
Tai Sing Lee and Alan L. Yuille
- Published in print:
- 2006
- Published Online:
- August 2013
- ISBN:
- 9780262042383
- eISBN:
- 9780262294188
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262042383.003.0008
- Subject:
- Neuroscience, Disorders of the Nervous System
Image segmentation is a process that partitions image into regions which can correspond to 3D surfaces in the visual scene or parts of a 3D surface defined by texture or color. This chapter presents ...
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Image segmentation is a process that partitions image into regions which can correspond to 3D surfaces in the visual scene or parts of a 3D surface defined by texture or color. This chapter presents computational theories that perform image segmentation in terms of efficient encoding of regions, and also discusses some neurophysiological experiments which suggest the relevance of the function and mechanism of the primary visual cortex in image segmentation.Less
Image segmentation is a process that partitions image into regions which can correspond to 3D surfaces in the visual scene or parts of a 3D surface defined by texture or color. This chapter presents computational theories that perform image segmentation in terms of efficient encoding of regions, and also discusses some neurophysiological experiments which suggest the relevance of the function and mechanism of the primary visual cortex in image segmentation.
Hector J. Levesque
- Published in print:
- 2012
- Published Online:
- August 2013
- ISBN:
- 9780262016995
- eISBN:
- 9780262301411
- Item type:
- book
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262016995.001.0001
- Subject:
- Computer Science, Artificial Intelligence
This book guides students through an exploration of the idea that thinking might be understood as a form of computation. Students make the connection between thinking and computing by learning to ...
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This book guides students through an exploration of the idea that thinking might be understood as a form of computation. Students make the connection between thinking and computing by learning to write computer programs for a variety of tasks that require thought, including solving puzzles, understanding natural language, recognizing objects in visual scenes, planning courses of action, and playing strategic games. The material is presented with minimal technicalities and is accessible to undergraduate students with no specialized knowledge or technical background beyond high school mathematics. Students use Prolog, learning to express what they need as a Prolog program and letting Prolog search for answers. After an introduction to the basic concepts, the book offers three chapters on Prolog, covering back-chaining, programs and queries, and how to write the sorts of Prolog programs used in the book. The book follows this with case studies of tasks that appear to require thought, then looks beyond Prolog to consider learning, explaining, and propositional reasoning. Most of the chapters conclude with short bibliographic notes and exercises.Less
This book guides students through an exploration of the idea that thinking might be understood as a form of computation. Students make the connection between thinking and computing by learning to write computer programs for a variety of tasks that require thought, including solving puzzles, understanding natural language, recognizing objects in visual scenes, planning courses of action, and playing strategic games. The material is presented with minimal technicalities and is accessible to undergraduate students with no specialized knowledge or technical background beyond high school mathematics. Students use Prolog, learning to express what they need as a Prolog program and letting Prolog search for answers. After an introduction to the basic concepts, the book offers three chapters on Prolog, covering back-chaining, programs and queries, and how to write the sorts of Prolog programs used in the book. The book follows this with case studies of tasks that appear to require thought, then looks beyond Prolog to consider learning, explaining, and propositional reasoning. Most of the chapters conclude with short bibliographic notes and exercises.
