Geometry and Visual Space from Antiquity to the Early Moderns

Space ◽  
2020 ◽  
pp. 184-222
Author(s):  
Gary Hatfield
Keyword(s):  
Visual Perception ◽  
Distance Perception ◽  
Visual Space ◽  
Field Of View ◽  
Size Perception ◽  
Mental Calculation ◽  
Straight Lines ◽  
Comparative Examination

This chapter examines the development of a geometrical framework for understanding and explaining spatial aspects of visual perception, including perception of the sizes, shapes, and positions of things in the field of view. The structure of this framework is built on the fact that vision typically occurs in straight lines (rectilinearly). Within this framework, the chapter selectively focuses on size perception. This focus allows for a comparative examination of how a single problem was treated geometrically by various theorists, ancient, medieval, and modern. The theorists examined are Euclid and Ptolemy, who were extramissionists, and Ibn al-Haytham, Kepler, Descartes, and Berkeley, each of whom adopted, in one way or another, an intromissionist scheme. In comparing Descartes and Berkeley, notice is taken of Berkeley’s interpretive bent in treating Descartes’s account of distance perception in a way that requires mental calculation, where Descartes sometimes offered psychophysiological mechanisms (avoiding mental calculation).

Distance Perception within near Visual Space

Perception ◽  
10.1068/p3119 ◽  
2001 ◽  
Vol 30 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Alain Viguier ◽  
Gilles Clément ◽  
Yves Trotter
Keyword(s):  
Distance Perception ◽  
Visual Space

Visual Perception of Apparent Motion Abides by Minimization Principles of Geometry

2021 ◽  
Author(s):  
Yaxin Liu ◽  
Stella F. Lourenco
Keyword(s):  
Visual Perception ◽  
Target Detection ◽  
Apparent Motion ◽  
Visual Space ◽  
Detection Task ◽  
Newtonian Physics ◽  
Kinematic Geometry ◽  
Shed Light ◽  
Target Detection Task ◽  
Perceptual Phenomenon

Apparent motion is a robust perceptual phenomenon in which observers perceive a stimulus traversing the vacant visual space between two flashed stimuli. Although it is known that the “filling-in” of apparent motion favors the simplest and most economical path, the interpolative computations remain poorly understood. Here, we tested whether the perception of apparent motion is best characterized by Newtonian physics or kinematic geometry. Participants completed a target detection task while Pacmen- shaped objects were presented in succession to create the perception of apparent motion. We found that target detection was impaired when apparent motion, as predicted by kinematic geometry, not Newtonian physics, obstructed the target’s location. Our findings shed light on the computations employed by the visual system, suggesting specifically that the “filling-in” perception of apparent motion may be dominated by kinematic geometry, not Newtonian physics.

scholarly journals Influence of the Size of the Field of View on Visual Perception While Running in a Treadmill-Mediated Virtual Environment

2019 ◽  
Vol 10 ◽  
Author(s):  
Martina Caramenti ◽  
Paolo Pretto ◽  
Claudio L. Lafortuna ◽  
Jean-Pierre Bresciani ◽  
Amandine Dubois
Keyword(s):  
Visual Perception ◽  
Virtual Environment ◽  
Field Of View

Independent Effects of Error Magnification and Field of View on Compensatory Tracking Performance

1966 ◽  
Vol 8 (6) ◽  
pp. 563-567
Author(s):  
Russell L. Smith ◽  
David R. Garfinkle ◽  
John Lyman
Keyword(s):  
Visual Perception ◽  
Reaction Times ◽  
Optical Gain ◽  
Field Of View ◽  
Tracking Performance ◽  
Facilitative Effect ◽  
Visual Mode ◽  
Optical Magnification ◽  
Per Se ◽  
Independent Effects

This experiment evaluated the independent effects of error magnification and field of view on compensatory tracking performance. Both display and optical magnification were investigated. In general, the results demonstrated that: (1) the facilitative effect on performance of display magnification was primarily due to the concomitant field of view reduction and not magnification per se; (2) optical magnification facilitated performance but subsequent display gain increases had no further affect; (3) regardless of visual mode employed, optimum performance levels on a complex trajectory converged at approximately the same field of view. In was suggested that increasing the optical gain or decreasing the field of view resulted in subjects reducing their reaction times to target movements. No evidence was found which indicated that magnification facilitated visual perception.

Relationship Between Auditory Context and Visual Distance Perception: Effect of Musical Expertise in the Ability to Translate Reverberation Cues Into Room-Size Perception

Perception ◽  
2018 ◽  
Vol 47 (8) ◽  
pp. 873-880
Author(s):  
Pablo E. Etchemendy ◽  
Ignacio Spiousas ◽  
Ramiro Vergara
Keyword(s):  
Distance Perception ◽  
Anechoic Chamber ◽  
The Other ◽  
Size Perception ◽  
Size Information ◽  
Musical Expertise ◽  
Room Size ◽  
Visual Distance

In a recently published work by our group [ Scientific Reports, 7, 7189 (2017)], we performed experiments of visual distance perception in two dark rooms with extremely different reverberation times: one anechoic ( T ∼ 0.12 s) and the other reverberant ( T ∼ 4 s). The perceived distance of the targets was systematically greater in the reverberant room when contrasted to the anechoic chamber. Participants also provided auditorily perceived room-size ratings which were greater for the reverberant room. Our hypothesis was that distance estimates are affected by room size, resulting in farther responses for the room perceived larger. Of much importance to the task was the subjects’ ability to infer room size from reverberation. In this article, we report a postanalysis showing that participants having musical expertise were better able to extract and translate reverberation cues into room-size information than nonmusicians. However, the degree to which musical expertise affects visual distance estimates remains unclear.

Full Leg Control of a Quadruped Robot Using Linear Visual Servoing with a Stereo Omnidirectional Camera

2011 ◽  
Vol 5 (2) ◽  
pp. 241-246
Author(s):  
Yukinari Inoue ◽  
◽  
Noriaki Maru ◽  
Keyword(s):  
Visual Servoing ◽  
Visual Space ◽  
Quadruped Robot ◽  
The Body ◽  
Field Of View ◽  
Transformation Equation ◽  
Stereo Camera ◽  
Omnidirectional Camera ◽  
Quadruped Robots ◽  
Omnidirectional Image

The authors have previously proposed foot tip control for quadruped robots using linear visual servoing (LVS) with a normal stereo camera. However, a normal stereo camera has a narrow field of view and is incapable of seeing all four legs simultaneously. Consequently, it has been a problem that the control of all the legs have required that the rotatation of the camera be controlled. This article proposes a method by which a stereo omnidirectional camera is provided at a position low on the body to control all four legs through LVS. In this article, we at first present a transformation equation from an omnidirectional image to a binocular visual space, and we develop a servo equation of LVS in which an omnidirectional image is used. Then, through simulation, we confirm trajectories with the LVS applied to foot tip control. We also conduct an experiment using TITAN-VIII to demonstrate the efficacy of the proposed method.

scholarly journals The Mechanisms of Size Constancy

2015 ◽  
Vol 28 (3-4) ◽  
pp. 253-283 ◽  
Author(s):  
Irene Sperandio ◽  
Irene Sperandio ◽  
Philippe A. Chouinard
Keyword(s):  
Visual Experience ◽  
Distance Perception ◽  
Brain Area ◽  
Size Perception ◽  
Retinal Images ◽  
Size Constancy ◽  
Constant Size ◽  
Sensory Modalities ◽  
The Brain

Size constancy is the result of cognitive scaling operations that enable us to perceive an object as having the same size when presented at different viewing distances. In this article, we review the literature on size and distance perception to form an overarching synthesis of how the brain might combine retinal images and distance cues of retinal and extra-retinal origin to produce a perceptual visual experience of a world where objects have a constant size. A convergence of evidence from visual psychophysics, neurophysiology, neuropsychology, electrophysiology and neuroimaging highlight the primary visual cortex (V1) as an important node in mediating size–distance scaling. It is now evident that this brain area is involved in the integration of multiple signals for the purposes of size perception and does much more than fulfil the role of an entry position in a series of hierarchical cortical events. We also discuss how information from other sensory modalities can also contribute to size–distance scaling and shape our perceptual visual experience.

scholarly journals A panoramic synthetic vision model for improving collision avoidance in crowd simulation

2015 ◽  
Vol 6 (2) ◽  
pp. 1
Author(s):  
Ricardo Bustamante de Queiroz ◽  
Teófilo Dutra ◽  
Creto Vidal ◽  
Joaquim Cavalcante-Neto
Keyword(s):  
Virtual Reality ◽  
Visual Perception ◽  
Collision Avoidance ◽  
Vision System ◽  
Crowd Simulation ◽  
Field Of View ◽  
Panoramic View ◽  
Natural Manner ◽  
Synthetic Vision ◽  
The Common

Crowd Simulation is very important in many virtual reality applications, because it improves the sense of immersion of the users by making the population of agents in the environment to move as real crowds do. Recently, models for simulating crowds, in which each agent is equipped with a synthetic vision system, have shown interesting results regarding the natural manner in which the agents navigate inside the environment thanks to their visual perception. In this article, we propose an upgrade to the agent’s visual system with a panoramic view in order to allow an agent to expand its vision beyond the limit of 180o imposed by the common projection provided by rendering APIs. Also, we analyze different parameters, which are used to define the field of view, to investigate the influence they have on the agent’s behavior. The impacts that those changes may cause on the efficiency of the algorithms are also analysed. A visible change on the agent’s behavior is achieved by using the technique, with a slight loss of performance.

scholarly journals Visual Perception from Object Scanning as Revealed by Electrooculography

Ophthalmology ◽  
2018 ◽  
pp. 98-114
Author(s):  
Anwesha Banerjee ◽  
Ankita Mazumder ◽  
Poulami Ghosh ◽  
D. N. Tibarewala
Keyword(s):  
Eye Movements ◽  
Visual Perception ◽  
Field Of View ◽  
Visual Environment ◽  
Human Beings ◽  
Fixational Eye Movements ◽  
Visual Processes ◽  
Points Of Interest ◽  
Do So

We the human beings are blessed by the nature to become well competent for performing highly precise and copious visual processes with how ever a restricted field of view. Howbeit, this process of visual perception is, to a great extent, controlled by the saccades or more commonly the eye movements. The positioning and accommodation of eyes allows an image to be placed (or fixed) in the fovea centralis of the eyes but although we do so to fix our gaze at a particular object, our eyes continuously move. Even though these fixational eye movements includes magnitude that should make them visible to us yet we remain oblivious to them. Microsacades, drifts and tremors that occurs frequently during fixational eye movements, contribute largely to the visual perception. We use saccades several times per second to move the fovea between points of interest and build an understanding of our visual environment.

scholarly journals On Riemannian Geometries of Visual Space

2021 ◽  
Author(s):  
Jacek Turski
Keyword(s):  
Riemannian Geometry ◽  
Physical Space ◽  
Visual Space ◽  
Gaze Direction ◽  
Relative Depth ◽  
Metric Tensor ◽  
The Gaze ◽  
Zero Curvature ◽  
Riemannian Geometries ◽  
Straight Lines

This is a study of the phenomenal geometries constructed in the Riemannian geometry framework from simulated iso-disparity conics in the horizontal visual plane of the binocular system with the asymmetric eyes (AEs). The iso-disparity conic's arcs in the Cyclopean direction are the frontal visual geodesics. For the eyes' resting vergence posture, which depends on parameters of the AE, the iso-disparity conics are frontal straight lines in physical space. For all other fixations, the iso-disparity conics consist of families of the ellipses or hyperbolas depending on both the AE's parameters and the bifoveal fixation. An assumption underlying the relevant architecture of the human visual system is combined with results from simulated iso-disparity straight lines, giving the relative depth as a function of the distance. This establishes the metric tensor in binocular space of fixations for the eyes' resting vergence posture. The resulting geodesics in the gaze direction, give the distance to the horizon and zero curvature. For all other fixations, only the sign of the curvature can be inferred from the global behavior of the simulated iso-disparity conics.

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