scholarly journals Human Visual Perception of Two-Dimensional Symmetry

2017 ◽  
Author(s):  
Jeremy Cole ◽  
David Reitter ◽  
Yanxi Liu
Keyword(s):  
Visual Perception ◽  
Shortest Path ◽  
Pattern Perception ◽  
Two Dimensional ◽  
Human Visual Perception ◽  
Symmetry Perception ◽  
Wallpaper Groups

Most literature on symmetry perception has focused on bilateralreflection symmetry with some suggesting that it isthe only type of symmetry humans can perceive (Wilson &Wilkinson, 2002). Using image stimuli generated from themathematically well-defined seventeen wallpaper groups, thisstudy demonstrates that humans can discriminate various symmetriesfound in 2D wallpaper patterns (Liu, Hel-Or, Kaplan,Van Gool, et al., 2010). Furthermore, the results demonstratethe features which contribute to wallpaper pattern perception.All wallpaper groups but one were found to be reliably distinguishable(p < 0:05). Additionally, as wallpaper patterns canbe arranged in a hierarchy, we propose a metric to quantify thesimilarity of their perception using the shortest path in this hierarchy.This subgroup distance was found to be a factor in alikely model of pattern perception.

scholarly journals The human visual system preserves the hierarchy of two-dimensional pattern regularity

2021 ◽  
Vol 288 (1955) ◽  
pp. 20211142
Author(s):  
Peter J. Kohler ◽  
Alasdair D. F. Clarke
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Brain Activity ◽  
Natural Scenes ◽  
Two Dimensional ◽  
Fine Grained ◽  
Lower Amplitude ◽  
Symmetry Perception ◽  
High Level ◽  
Wallpaper Groups

Symmetries are present at many scales in natural scenes. Humans and other animals are highly sensitive to visual symmetry, and symmetry contributes to numerous domains of visual perception. The four fundamental symmetries—reflection, rotation, translation and glide reflection—can be combined into exactly 17 distinct regular textures. These wallpaper groups represent the complete set of symmetries in two-dimensional images. The current study seeks to provide a more comprehensive description of responses to symmetry in the human visual system, by collecting both brain imaging (steady-state visual evoked potentials measured using high-density EEG) and behavioural (symmetry detection thresholds) data using the entire set of wallpaper groups. This allows us to probe the hierarchy of complexity among wallpaper groups, in which simpler groups are subgroups of more complex ones. We find that both behaviour and brain activity preserve the hierarchy almost perfectly: subgroups consistently produce lower-amplitude symmetry-specific responses in visual cortex and require longer presentation durations to be reliably detected. These findings expand our understanding of symmetry perception by showing that the human brain encodes symmetries with a high level of precision and detail. This opens new avenues for research on how fine-grained representations of regular textures contribute to natural vision.

scholarly journals A Quantitative Method for Estimation of Quality of Screens Color

2018 ◽  
pp. 39-46
Author(s):  
O. Kupko
Keyword(s):  
Visual Perception ◽  
Color Space ◽  
Three Dimensional ◽  
Dimensional Case ◽  
Two Dimensional ◽  
Color Spaces ◽  
Human Visual Perception ◽  
Insufficient Amount ◽  
History Of ◽  
The Difference

The history of the issue on creation of uniform color spaces is analyzed. It is noted that the calculations based on the results of spectral measurements do not adequately correspond to the human visual perception. For all existing color spaces, it has been proposed to create a uniform metric, a me­thod for determining the length, area and volume in the corresponding spaces, one that corresponds to the human visual perception. The metric is based on MacAdam ellipses, that is, on the threshold perception of the difference in colors. For each point of any color space (two or three measurements) is determined the area of space around each point, within which a person is not able to fix the difference in color. The area is characterized by either an ellipse (two-dimensional case) or an ellipsoid (three-dimensional case). To characterize an ellipse, it is necessary to have three parameters — two axes and the angle of slope. To characterize an ellipsoid, it is necessary to have five parameters — three axes and two angle of slope. The number of sections along a line, along a plane, or in a volume is a measure of length, a plane, or in a volume and sets a metric. The connection of the existing systems for determining color and visual perception of a person is carried out using scales. Scales associate the length, area or volume of any color system with a person’s visual perception. The scale depends on the point of space and the direction in which the movement takes place. As a result, a large number of scales (more than the number of colors, because it is necessary to know the angles of inclination of the ellipses) are needed, which must be agreed by the international community. To use this amount of data and for the corresponding calculations, it is necessary to have an agreed international calculation procedure. It is established, that as a result of the development of computing technology, a large amount of data and a large amount of computation are not a significant obstacle. The obstacle is an insufficient amount of consistent data, that is, it is necessary to perform additional measurements and approvals to determine the areas of space around each point of the color space within which a person is not able to fix the difference in color. A schematic diagram of the measurements and the equipment with the help of which it is possible to carry out the corresponding measurements are proposed. Estimates of the greatest labour intensity of such works are carried out. It is determined what is the most important part of these works is possible to carry out within a few years. For two-dimensional spaces (x, y and u, v), using the results of the classical work of McAdam, we determined the scales for connecting the lengths and areas in these spaces with the visual perception of the human eye. The directions in which the scales are largest or smallest are determined. For these two directions there are given scales that relate the distances and areas of the spaces (x,y and u,v) with the human visual perception. It is noted, that the work on creating the metrics has a clear phased structure, some parts of the work, i.e.: the development of software and programming, the development of stabilized radiation sources, the development of comparing tools and experimental research can be carried out independently. Conclusions and suggestions are made.

An improved line continuation model in human visual perception

1993 ◽  
Vol 26 (6) ◽  
pp. 825-842 ◽  
Author(s):  
Yung-Sheng Chen ◽  
Shih-Liang Chang ◽  
Wen-Hsing Hsu
Keyword(s):  
Visual Perception ◽  
Human Visual Perception

scholarly journals Waveguide combiners for mixed reality headsets: a nanophotonics design perspective

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 41-74
Author(s):  
Bernard C. Kress ◽  
Ishan Chatterjee
Keyword(s):  
Visual Perception ◽  
Mixed Reality ◽  
Deep Understanding ◽  
Large Field ◽  
High Angular Resolution ◽  
List Type ◽  
Human Visual Perception ◽  
Perception System ◽  
Social Comfort ◽  
Hardware Architectures

AbstractThis paper is a review and analysis of the various implementation architectures of diffractive waveguide combiners for augmented reality (AR), mixed reality (MR) headsets, and smart glasses. Extended reality (XR) is another acronym frequently used to refer to all variants across the MR spectrum. Such devices have the potential to revolutionize how we work, communicate, travel, learn, teach, shop, and are entertained. Already, market analysts show very optimistic expectations on return on investment in MR, for both enterprise and consumer applications. Hardware architectures and technologies for AR and MR have made tremendous progress over the past five years, fueled by recent investment hype in start-ups and accelerated mergers and acquisitions by larger corporations. In order to meet such high market expectations, several challenges must be addressed: first, cementing primary use cases for each specific market segment and, second, achieving greater MR performance out of increasingly size-, weight-, cost- and power-constrained hardware. One such crucial component is the optical combiner. Combiners are often considered as critical optical elements in MR headsets, as they are the direct window to both the digital content and the real world for the user’s eyes.Two main pillars defining the MR experience are comfort and immersion. Comfort comes in various forms: –wearable comfort—reducing weight and size, pushing back the center of gravity, addressing thermal issues, and so on–visual comfort—providing accurate and natural 3-dimensional cues over a large field of view and a high angular resolution–vestibular comfort—providing stable and realistic virtual overlays that spatially agree with the user’s motion–social comfort—allowing for true eye contact, in a socially acceptable form factor.Immersion can be defined as the multisensory perceptual experience (including audio, display, gestures, haptics) that conveys to the user a sense of realism and envelopment. In order to effectively address both comfort and immersion challenges through improved hardware architectures and software developments, a deep understanding of the specific features and limitations of the human visual perception system is required. We emphasize the need for a human-centric optical design process, which would allow for the most comfortable headset design (wearable, visual, vestibular, and social comfort) without compromising the user’s sense of immersion (display, sensing, and interaction). Matching the specifics of the display architecture to the human visual perception system is key to bound the constraints of the hardware allowing for headset development and mass production at reasonable costs, while providing a delightful experience to the end user.

Social Attribution and Explanation

2017 ◽  
Author(s):  
Denis Hilton
Keyword(s):  
Visual Perception ◽  
Final Section ◽  
Higher Order ◽  
Situation Models ◽  
Causal Connection ◽  
Human Visual Perception ◽  
Social Attribution ◽  
Text Understanding ◽  
Causal Selection ◽  
Partial Correction

Attribution processes appear to be an integral part of human visual perception, as low-level inferences of causality and intentionality appear to be automatic and are supported by specific brain systems. However, higher-order attribution processes use information held in memory or made present at the time of judgment. While attribution processes about social objects are sometimes biased, there is scope for partial correction. This chapter reviews work on the generation, communication, and interpretation of complex explanations, with reference to explanation-based models of text understanding that result in situation models of narratives. It distinguishes between causal connection and causal selection, and suggests that a factor will be discounted if it is not perceived to be connected to the event and backgrounded if it is perceived to be causally connected to that event, but is not selected as relevant to an explanation. The final section focuses on how interpersonal explanation processes constrain causal selection.

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