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The perception and misperception of optical defocus, shading, and shape.
Scott Wj Mooney1, Phillip J Marlow1, Barton L Anderson1
1School of Psychology, The University of Sydney, Sydney, Australia.
Elife
|July 13, 2019
Summary
The human visual system struggles to differentiate between surface blur and optical defocus. Misperceptions arise when focused shading is seen as blurred, or blur is attributed to surface properties.
Area of Science:
- Visual perception
- Computational vision
- Image processing
Background:
- The visual system interprets retinal images to understand the 3D world.
- Research has explored estimating environmental image structure and optical blur separately.
- Limited understanding exists on distinguishing environmental cues from optical defocus.
Purpose of the Study:
- Investigate how the visual system differentiates environmental image structure from optical defocus.
- Identify conditions under which the visual system succeeds or fails in this distinction.
- Explore the relationship between blur computation and surface properties.
Main Methods:
- Experimental manipulation of focused surface shading and optical blur.
- Analysis of perceptual misjudgments.
- Investigating the influence of shading gradients and sharp contours on perception.
Main Results:
- Fully focused surface shading can be misperceived as defocused.
- Optical blur can be misattributed to surface material properties and shape.
- Misperceptions are linked to the interplay between shading gradients and sharp contours.
Conclusions:
- Distinguishing environmental structure from optical defocus is a fundamental perceptual challenge.
- Blur computations are intrinsically linked to the perception of surface shape, material, and illumination.
- The visual system's ability to solve this problem is context-dependent.
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