The perception and misperception of optical defocus, shading, and shape

Abstract
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Abstract

The human visual system is tasked with recovering the different physical sources of optical structure that generate our retinal images. Separate research has focused on understanding how the visual system estimates (a) environmental sources of image structure and (b) blur induced by the eye's limited focal range, but little is known about how the visual system distinguishes environmental sources from optical defocus. Here, we present evidence that this is a fundamental perceptual problem and provide insights into how and when the visual system succeeds and fails in solving it. We show that fully focused surface shading can be misperceived as defocused and that optical blur can be misattributed to the material properties and shape of surfaces. We further reveal how these misperceptions depend on the relationship between shading gradients and sharp contours, and conclude that computations of blur are inherently linked to computations of surface shape, material, and illumination.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

Scott WJ Mooney

School of Psychology, The University of Sydney, Sydney, Australia

For correspondence
scm2011@med.cornell.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-0094-7638
Phillip J Marlow

School of Psychology, The University of Sydney, Sydney, Australia

Competing interests
The authors declare that no competing interests exist.
Barton Anderson

School of Psychology, The University of Sydney, Sydney, Australia

Competing interests
The authors declare that no competing interests exist.

Funding

Commonwealth of Australia (Australian Postgraduate Award)

Scott WJ Mooney

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Human subjects: Informed consent and consent to publish was obtained from each participant in accordance with experimental protocol 2012/2759 approved by the Human Research Ethics Committee (HREC) at the University of Sydney.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.