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.
- Scott WJ Mooney
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
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.
- Roland W Fleming, University of Giessen, Germany
- Received: May 5, 2019
- Accepted: July 11, 2019
- Accepted Manuscript published: July 12, 2019 (version 1)
© 2019, Mooney et al.
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