Scene perception

9.1 Scene Perception PSYC 579 Topic Presentation, University of British Columbia

Diliara Nasirova

School of Interactive Art and Technology, Simon Fraser University

March 23, 2011

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Outline

1.  Introduction to Scene Perception

2.  Theories of Scene Perception ■  Coherence Theory ■  Virtual Representation ■  Triadic Architecture

3.  Application to visual design ■  Visual Transitions ■  Attentional Coercion

Diliara Nasirova | PSYC 579 | March 23, 2011

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Introduction Scene Perception

•  Scene Perception is a visual perception of an environment as viewed by an observer at any given time.


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Introduction Belief about vision

•  Our brains contain detailed, picture-like representation of the scene


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Introduction Phenomena against the belief •  Inattentional Blindness:

•  The failure to notice the presence of unattended stimuli, even when they are presented within an observer’s field of view

•  Change Blindness: •  The failure to see changes even

when they are large, anticipated and repeatedly made if they are made during a visual disturbance


Simons and Chabris (1999) “Gorillas in Our Midst: Sustained Inattentional Blindness for Dynamic Events”

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Introduction Phenomena against the belief •  Inattentional Blindness:

•  The failure to notice the presence of unattended stimuli, even when they are presented within an observer’s field of view

•  Change Blindness: •  The failure to see changes even

when they are large, anticipated and repeatedly made if they are made during a visual disturbance


Rensink RA (2002). Internal vs. external information in visual perception.

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Introduction Change Blindness demo


http://www.cs.ubc.ca/~rensink/flicker/download/Harborside.mov

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Introduction If a visual buffer existed…


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Introduction If there is no buffer…


1.  How is it possible to see change at all? 2.  How might human vision operate?

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Theories of Scene Perception Coherence theory

•  Coherence theory is based on three related hypotheses 1.  Volatile proto-objects formed rapidly in the visual field (without attention) 2.  Focused attention selects some proto-objects and forms coherence field 3.  Release of focused attention (back to proto-objects)


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•  Coherence theory is based on three related hypotheses 1.  Volatile proto-objects formed rapidly in the visual field (without attention) 2. Focused attention selects some proto-objects and forms coherence field 3. Release of focused attention (back to proto-objects)


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•  Coherence theory is based on three related hypotheses 1.  Volatile proto-objects formed rapidly in the visual field (without attention) 2.  Focused attention selects some proto-objects and forms coherence field 3.  Release of focused attention (back to proto-objects)


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Theories of Scene Perception Coherence theory •  Why observers fail to detect changes in "attended" objects?

■  Small number of items can be attended at any time ■  Not all details can be represented in a coherence field ■  Change blindness results



•  Counterintuitive implications: ■  Only a few items can be

represented ■  The representation details is

limited

•  Why do we not notice these limitations?


Rensink RA (2000a). The dynamic representation of scenes.

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Theories of Scene Perception Virtual Representation


•  For most tasks, only one object is in play at any time:

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Theories of Scene Perception Virtual Representation


•  Idea of virtual representation:

■  Create a coherent, detailed representation only of a few objects needed for the task at hand

■  Details about any object should be available on request

•  Provide large savings in computational

resources: memory & processing time

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Theories of Scene Perception Virtual Representation •  For successful use of virtual representation

eye movements and attentional shifts should be made ■  to the appropriate object ■  at the appropriate time.

•  But what directs these movements and shifts?


Rensink RA (2000). Scene perception.

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Theories of Scene Perception Triadic Architecture •  A possible solution is a triadic architecture with three systems


Rensink RA (2000). Scene perception.

layout gist

object sketch

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Theories of Scene Perception Triadic Architecture


Rensink RA (2002). Internal vs. external information in visual perception.

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Theories of Scene Perception Triadic Architecture •  The representation of a scene

involves the dynamic interaction of three systems.

•  A complete representation of the

scene is never constructed - only one coherent object represented at any one time


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Application to Visual Design Visual Transitions

•  It is possible for displays to promote or prevent the conditions that create change blindness.

■  Saccade ■  Eye blinks ■  Occlusion ■  Movie cuts ■  Gradual transitions ■  Movement

Diliara Nasirova | PSYC 579 | Jan 26, 2011

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Application to Visual Design Visual Transitions

Diliara Nasirova | PSYC 579 | Jan 26, 2011

•  Design of displays robust to change blindness: ■  Minimizing saccades (important

information close together) ■  Minimizing number of dynamic

events in the background & foreground

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Application to Visual Design Visual Transitions •  Change Detection in 3D

Parametric Systems: Human-Centered Interfaces for Change Visualization

1. Change blindness 2. On model (A) and

on periphery (B) visualizations

3. Combined views.


http://www.bentley.com/

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Application to Visual Design Visual Transitions •  Change Detection in 3D

Parametric Systems: Human-Centered Interfaces for Change Visualization

1. Change blindness 2. On model (A) and

on periphery (B) visualizations

3. Combined views.


29 Diliara Nasirova | PSYC 579 | March 23, 2011

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Application to Visual Design Attention Coercion •  Taking control of attention and

making the observer see (or not see) any given part of the display.

•  Can be carried out in different ways:

■  High-level interest


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Application to Visual Design Attention Coercion


•  Taking control of attention and making the observer see (or not see) any given part of the display.

•  Can be carried out in different ways: ■  High-level interest ■  Mid-level directives

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Application to Visual Design Attention Coercion


•  Taking control of attention and making the observer see (or not see) any given part of the display.

•  Can be carried out in different ways: ■  High-level interest ■  Mid-level directives ■  Low-level salience

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Conclusion


1.  Change blindness is very general phenomenon.

2.  Only one coherent object can be attended at a time.

3.  The perception of a scene is inherently dynamic.

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Questions?

•  Thank you…


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References

1.  Rensink RA (2002). Internal vs. external information in visual perception. Proceedings of the Second International Symposium on Smart Graphics: 63-70. [Smart Graphics 2; Hawthorne, NY, USA.]

2.  Rensink RA (2000). Scene perception. In AE Kazdin (ed.), Encyclopedia of Psychology, vol. 7. (pp. 151-155). New York: Oxford University Press.

3.  Rensink RA (2000a). The dynamic representation of scenes. In DJ Simons (ed.) Change Blindness and Visual Memory (pp. 17-42). London: Psychology Press.

4.  Varakin DA, Levin DT, and Fidler R (2008). Unseen and unaware: implications of recent research on failures of visual awareness for human-computer interface design. Hum.-Comput. Interact., 19:389–422


Scene perception

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