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Why the visual recognition system might encode the effects of illumination
M J Tarr1, D Kersten, H H Bülthoff
1Department of Cognitive and Linguistic Sciences, Brown University, Providence, RI 02912, USA. michaelvtarr@brown.edu
Vision Research
|November 3, 1998
Summary
Object recognition is sensitive to lighting conditions, impacting visual memory and shape perception. Changes in illumination, particularly shadow edges, affect how we recognize 3-D objects.
Area of Science:
- Cognitive Psychology
- Computer Vision
- Visual Perception
Background:
- Object recognition is challenged by variations in lighting conditions.
- Illumination affects object appearance through shading and cast shadows.
Purpose of the Study:
- To investigate the sensitivity of object recognition to illumination changes.
- To determine if illumination effects influence visual memory and shape interpretation.
Main Methods:
- Experiments using 3-D objects with varying lighting (left/right).
- Tasks included same-different judgments and object naming.
- Manipulated cast shadows, shadow edges, and object familiarity.
Main Results:
- Response time costs observed with illumination changes, especially with cast shadows.
- Sensitivity was affected by illumination changes, particularly for less familiar objects and with white shadows.
- Naming familiar objects showed costs in sensitivity and response time under unfamiliar lighting.
Conclusions:
- Illumination effects, like shadow edges, impact visual memory.
- These effects help disambiguate three-dimensional object shape.
- Visual system models illumination relative to object shape, not just image properties.