Visual Rays are Parallel
Abstract
We show that human observers using monocular viewing treat the pencil of 'visual rays' that diverges from the vantage point as experientally parallel. This oddity becomes very noticeable in the case of wide-angle presentations, where the angle subtended by a pair of visual rays may be as large as the angular size of the display. In our presentations such angles subtended over 100 deg. There are various ways to demonstrate the effect; in this study we measure the attitudes of pictorial objects that appear to be situated in mutually parallel attitudes in pictorial space. Our finding is that such objects appear parallel if they are similarly oriented with respect to the local visual rays. This leads to 'errors' in the judgment of mutual orientations of up to 100 deg. Although this appears to be the first quantitative study of the effect, we trace it to qualitative reports by Helmholtz (late 19th century) and Kepler (early 17th century) as well as speculation by early authors (AD 500). The effect has apparently been noticed by visual artists from the late middle ages to the present day.
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Even at close distances, perceptions differ from careful measurements.
“Even at close distances our perceptions differ from our careful measurements (Kappers 1999;Cuijpers et al. 2003;Koenderink et al. 2010;Pont et al. 2012)”
From The Interface Theory of Perception (2015) · cites this paper as Koenderink et al. 2010
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- Authors
- Koenderink, J., van Doorn, A., de Ridder, H., & Oomes, S.
- Affiliations
- Delft University of Technology (NL)
- Delft University of Technology, Faculty of Industrial Design, Landbergstraat 15, 2628 CE Delft, The Netherlands
- Corresponding author
- Koenderink, Jan
- ORCID
- Koenderink, Jan
- Venue
- Perception
- Publisher
- SAGE Publications
- Published
- 2010-01-01
- Volume
- 39
- Issue
- 9
- Pages
- 1163-1171
- ISSN
- 0301-0066 (ISSN-L)
- 1468-4233
- OpenAlex
- W1990282947
- Cited by
- 31
- References
- 14
- Citations by year
- 2025: 3 · 2024: 2 · 2023: 3 · 2021: 1 · 2019: 1 · 2018: 3 · 2017: 2 · 2016: 1 · 2015: 6 · 2014: 3 · 2013: 3
- FWCI
- 1.16
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Perception (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Life Sciences › Neuroscience › Cognitive Neuroscience › Visual perception and processing mechanisms
- Social Sciences › Arts and Humanities › Visual Arts and Performing Arts › Architecture and Art History Studies
- Life Sciences › Neuroscience › Cognitive Neuroscience › Aesthetic Perception and Analysis
- Keywords
- monocular viewing, pictorial space, orientation judgment, Helmholtz, Kepler, visual artists
- MeSH terms
- Female, Humans, Illusions, Male, Photic Stimulation, Space Perception, Visual Perception, Vision, Monocular
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