DOCSLIB.ORG

Durham E-Theses

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Durham E-Theses Durham E-Theses Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study FRONER, BARBARA How to cite: FRONER, BARBARA (2011) Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/3324/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study by Barbara Froner A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy School of Engineering and Computing Sciences Durham University United Kingdom Copyright °c 2011 by Barbara Froner Abstract Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study Barbara Froner In the last decade an increasing number of application ¯elds, including medicine, geoscience and bio-chemistry, have expressed a need to visualise and interact with data that are inherently three-dimensional. Stereoscopic 3D technologies can o®er a valid support for these operations thanks to the enhanced depth representation they can provide. However, there is still little understanding of how such technologies can be used e®ectively to support the performance of visual tasks based on accurate depth judgements. Existing studies do not provide a sound and complete explanation of the impact of di®erent visual and technical factors on depth perception in stereoscopic 3D environments. This thesis presents a new interpretative and contextualised analysis of the vision sci- ence literature to clarify the role of di®erent visual cues on human depth perception in such environments. The analysis identi¯es luminance contrast, spatial frequency, colour, blur, transparency and depth constancies as influential visual factors for depth perception and provides the theoretical foundation for guidelines to support the performance of accurate stereoscopic depth tasks. A novel assessment framework is proposed and used to conduct an empirical study to evaluate the performance of four distinct classes of 3D display technologies. The results suggest that 3D displays are not interchangeable and that the depth representation pro- vided can vary even between displays belonging to the same class. The study also shows that interleaved displays may su®er from a number of aliasing artifacts, which in turn may a®ect the amount of perceived depth. The outcomes of the analysis of the influential visual factors for depth perception and the empirical comparartive study are used to propose a novel universal 3D cursor prototype suitable to support depth-based tasks in stereoscopic 3D environments. The contribution includes a number of both qualitative and quantitative guidelines that aim to guarantee a correct perception of depth in stereoscopic 3D environments and that should be observed when designing a stereoscopic 3D cursor. ii Declaration The material contained within this thesis has not previously been submitted for a degree at Durham University or any other university. The research reported within this thesis has been conducted by the author unless indicated otherwise. This research has been documented, in part, within the following publications: ² B. Froner, N.S. Holliman and S.P. Liversedge. A comparative study of ¯ne depth perception on two-view 3D displays. Displays, 29(5):440-450, December 2008. ² N.S. Holliman, B. Froner and S.P. Liversedge. An application driven comparison of depth perception on desktop 3D displays. In Stereoscopic Displays and Virtual Reality Systems XIV, Proceedings of SPIE-IS&T Electronic Imaging, Volume 6490A, January 2007. Further relevant research conducted by the author has been documented in the following publications: ² N.S. Holliman, C. Baugh, C. Frenk, A. Jenkins, B. Froner, D. Hassaine, J. Helly, N. Metcalfe and T. Okamoto. Cosmic cookery: making a stereoscopic 3D animated movie. In Stereoscopic Displays and Virtual Reality Systems XVII, Proceedings of SPIE-IS&T Electronic Imaging, Volume 6055A, San Jose (CA-USA), January 2006. ² B. Froner and N.S. Holliman. Implementing an Improved Stereoscopic Camera Model, in Eurographics Theory and Practice of Computer Graphics 2005, Canter- bury (UK), June 2005. iii Copyright Notice The copyright of this thesis rests with the author. No quotation from it should be published without the author's prior written consent and information derived from it should be acknowledged. iv Acknowledgements I would like to express my gratitude to my academic supervisors Dr Nick Holliman and Prof Malcolm Munro, for providing me with the opportunity to pursue a PhD and for their advice and guidance during my research. A heartfelt thank you and love go to my husband Dr Nikolaos Galiatsatos for standing by me throughout these six years of part time studies and for putting up with my moods; I do not know how I would have been able to accomplish this without your continuous support, encouragement and patience. An equally heartfelt thanks goes to my parents Maria Grazia and Mario, for believing in me and supporting me throughout my entire education. Many thanks also to the rest of my family for their care and understanding. I am grateful to Prof Simon Liversedge, Dr Gustav Kuhn and Prof John Findley for their invaluable advice on statistics and perceptual psychology, and to Prof Luisa Mich for her encouragement and counsel. I also wish to thank my current employer, Foster Findley Associate, for their flexibility and for allowing me the time to complete my studies. Special thanks go to Dale Norton, Dr Oliver Vogt, Tamzin Cloke and Simon McConway for their excellent job in proof reading my draft and their suggestions, and to Dr James Lowell for the brilliant time we had when we were sharing the o±ce at uni. For their contribution to this work thanks also go to my research group members Dr Djamel Hassaine, Paul Gorley and Geng Sun. I would like to express a very special thank you to Stefano Pellegrini for his invaluable support and friendship, and for standing by me in di±cult times. Finally, I wish to thank Roberta Cristelli, Dr Adam Eckersley, Prof Keith Gallagher, Dr John Bailey, Dr Pim van 't Hof, Andrea Bonf¶aand all my other friends for their encouragement and continual belief. v Dedicated to my parents, Maria Grazia and Mario Hibiscus, Copyright °c by anaglyph (original title \Another flower, anaglyph", from anaglyph.deviantart.com) vi Contents 1 Introduction 1 1.1 Context of Work . 2 1.2 Statement of the Problem . 3 1.3 Aim and Objectives . 4 1.4 Thesis Overview and Research Contributions . 6 2 Depth Perception and Stereoscopic 3D Environments 9 2.1 Introduction . 9 2.2 Human Vision and Depth Perception . 10 2.2.1 Introduction . 10 2.2.2 Seeing in 3D . 10 2.2.3 Oculomotor Depth Cues . 11 2.2.4 Monocular Depth Cues . 14 2.2.5 Binocular Depth Cues and Stereopsis . 18 2.2.6 Depth Cues Integration . 20 2.3 Electronic 3D Display Systems . 21 2.3.1 Introduction to 3D Technologies . 21 2.3.2 Stereoscopic versus Autostereoscopic Systems . 22 2.3.3 3D Display Taxonomy . 22 vii CONTENTS viii Two-View Displays . 24 Multi-View Displays . 27 Volumetric Displays . 29 Others . 30 Summary . 31 2.3.4 Depth Perception on 3D Displays . 32 2.4 Depth-Based Tasks and Stereoscopic 3D Technologies . 34 2.4.1 Application Fields . 34 2.4.2 Previous Work on Stereoscopic 3D Cursors . 35 Medical Imaging . 36 Computer Graphics and 3D Aided Design . 36 Virtual Reality, Augmented Reality and Interaction Techniques . 41 Perception and Other Relevant Studies . 45 2.5 Conclusions . 47 3 Design of a Stereoscopic 3D Cursor 49 3.1 Introduction . 49 3.2 Visual Factors . 50 3.2.1 Luminance Contrast . 50 3.2.2 Spatial Frequency . 57 3.2.3 Colour . 61 3.2.4 Perspective, Distance and Depth Constancies . 70 3.2.5 Blur and Depth of Focus . 76 3.2.6 Occlusion and Transparency . 81 3.2.7 Summary of Visual Factors . 86 3.3 Technical Factors . 88 3.3.1 Display Resolution . 88 CONTENTS ix 3.3.2 Sampling and Aliasing Artifacts . 90 3.3.3 Image Interleaving . 91 3.3.4 Summary of Technical Factors . 92 3.4 Synthetic Cues . 93 3.5 General Discussion . 96 3.6 Conclusions . 98 4 Assessment of 3D Technologies: Methodology 100 4.1 Introduction . 100 4.2 Background . 101 4.3 Research Method . 103 4.3.1 Experimental Design . 103 4.3.2 Task and Stimuli . 104 4.3.3 Procedure . 107 4.4 Geometric Predictions . 108 4.4.1 Terminology and De¯nitions . 109 4.4.2 3D Display Classi¯cation . 110 4.4.3 Theoretical Predictions and Hypotheses . 111 4.5 Pilot Experiment . 115 4.5.1 Participants . 116 4.5.2 Experimental Conditions and Trial Blocks . 116 4.5.3 Apparatus . 117 4.5.4 Stimuli Details . 117 4.5.5 Results . 118 Score . 118 Response Time . 125 Subjective Results . 134 CONTENTS x 4.6 Conclusions . 137 5 Assessment of 3D Technologies: Results 139 5.1 Introduction . 139 5.2 Experimental Details .
Load more

Recommended publications
  • What Is Wrong with the No-Report Paradigm and How to Fix It Ned Block New York University Correspondence: [email protected]
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by PhilPapers Forthcoming in Trends in Cognitive Sciences What is wrong with the no-report paradigm and how to fix it Ned Block New York University Correspondence: [email protected] Key words: consciousness, perception, rivalry, frontal, global workspace, higher order Abstract Is consciousness based in prefrontal circuits involved in cognitive processes like thought, reasoning, and memory or, alternatively, is it based in sensory areas in the back of the neocortex? The no-report paradigm has been crucial to this debate because it aims to separate the neural basis of the cognitive processes underlying post-perceptual decision and report from the neural basis of conscious perception itself. However, the no-report paradigm is problematic because, even in the absence of report, subjects might engage in post-perceptual cognitive processing. Therefore, to isolate the neural basis of consciousness, a no-cognition paradigm is needed. Here, I describe a no-cognition approach to binocular rivalry and outline how this approach can help resolve debates about the neural basis of consciousness. Acknowledgement: Thanks to Jan Brascamp, Susan Carey, Thomas Carlson, David Carmel, David Chalmers, Christof Koch, Hakwan Lau, Matthias Michel, Michael Pitts, Dawid Potgieter and Giulio Tononi for comments on an earlier version. What is the Neural Basis of Consciousness? In recent years the scientific study of consciousness (see Glossary) has focused on finding the neural basis of consciousness in the brain. There are many theories of the neural basis of consciousness, but in broad strokes theories tend to divide on whether consciousness is rooted in the ‘front’ or the ‘back’ of the brain.
    [Show full text]
  • Spacespex™ Anaglyph—The Only Way to Bring 3Dtv to the Masses
    SPACESPEX™ ANAGLYPH—THE ONLY WAY TO BRING 3DTV TO THE MASSES By Michael Starks © M. Starks 2009 May be reproduced provided nothing is added, omitted or changed-- including this copyright notice. SpaceSpex™ is the name I applied to my versions of the orange/blue anaglyph technique in 1993. In fact the Gang Li/ColorCode and some models of SpaceSpex use amber or orange/brown rather than yellow, but they are on a continuum. Like all the bicolor anaglyph methods it is compatible with all video equipment and displays and I think it’s the best of the methods using inexpensive paper glasses with colored lenses. Until someone comes up with a way to put hundreds of millions of new 3D TV’s in homes which can use polarized glasses or LCD shutter glasses, anaglyph is going to be the only way for mass distribution of full color high quality 3D over cable, satellite, the web or on DVD. However the solution I have proposed for Set Top Boxes, PC’s, TV sets and DVD players for the last 20 years is to have user controls, so those with display hardware that permits polarized or shutter glasses or even autostereo viewing or who want 2D can make that choice from the single 3D video file. This is the method of the TDVision codec, Next3D, and of Peter Wimmer’s famous StereoScopic Player (a new version due end of 2009), (all of which should appear in hardware soon) and probably the best stereoplayer of all in Masuji Suto’s StereoMovie Maker, and is being incorporated in most well known software DVD and media players.
    [Show full text]
  • Visible Binocular Beats from Invisible Monocular Stimuli During Binocular Rivalry Thomas A
    Brief Communication 1055 Visible binocular beats from invisible monocular stimuli during binocular rivalry Thomas A. Carlson and Sheng He When two qualitatively different stimuli are presented in rivalry [14–16]. Random dot stereograms can be seen at the same time, one to each eye, the stimuli can either superimposed on, but not interacting with two orthogonal integrate or compete with each other. When they gratings engaged in rivalry, a phenomenon that Wolfe compete, one of the two stimuli is alternately termed ‘trinocular vision’ [5]. Hastorf and Myro also suppressed, a phenomenon called binocular rivalry reported that form and color rivalry could be de-coupled [1,2]. When they integrate, observers see some form of from one another ([17]; and see [5,18] for a general review). the combined stimuli. Many different properties (for Nevertheless, there are also challenges to the coexistence example, shape or color) of the two stimuli can induce of stereopsis and rivalry, particularly for the claim that they binocular rivalry. Not all differences result in rivalry, can be perceived at the same spatial location [6,7]. however. Visual ‘beats’, for example, are the result of integration of high-frequency flicker between the two During the experiment, an observer’s left eye was pre- eyes [3,4], and are thus a binocular fusion phenomenon. sented with a red triangle facing left and the right eye a It remains in dispute whether binocular fusion and green triangle facing right (each side of the triangle rivalry can co-exist with one another [5–7]. Here, we extended 2.1° visual angle), and each was illuminated, report that rivalry and beats, two apparently opposing respectively, with red or green light-emitting diodes (LEDs) phenomena, can be perceived at the same time within from behind a plastic diffuser.
    [Show full text]
  • British Orthoptic Journal Volume 1, 1939
    British Orthoptic Journal Volume 1, 1939 Loss of Central Fixation 15-19 I.Yoxall Some Observations on Partial Occlusion in Accommodative Squints 20- 22 E.Pemberton A few samples of Traumatic Heterophoria 23-27 S.Mayou Operative Impressions in Orthoptic Training 28-33 OM Duthie Summary of routine treatment given at the Manchester Royal 34-37 Eye Hospital E.Stringer Voluntary Diplopia 38-43 S.Mayou Paralysis of External Rectus; Treatment of Muscle Grafting 44-45 P.Jameson Evans Some Observations on Squint Operations 46-49 Dr Gordon Napier Suitability of cases for Orthoptic Training 50-53 CH.Bamford Occlusion 54-57 K.Bastow Some Recent Methods used in an Attempt to shorten Orthoptic treatment 58-62 S.Jackson History of Orthoptic treatment 63-65 CL Gimblett Occasional Divergent Squint 66 S.Jackson Unusual cases of divergent squint treated at the Manchester Royal Eye 67 Hospital E.Stringer Divergent Strabismus and its treatments 68-69 K.Bastow Divergent Squint 70 J.Strickland Approach to the Phorias 71-104 Wing Commander Livingstone Certain aspects of the Evolution of the eye 105 I.Mann BOJ Volume 2, 1944 Some Observations on accommodative squint 13-15 M.Parsons Some Observations on experimental work on the relation of squint 16-20 to emotional disturbances carried out at the Oxford Eye Hospital B.Hare Our Failures 21-24 E.Stringer Graded Squint Operations 25-32 J.Foster, EC Pemberton, SS Freedman Prognosis of postoperative Diplopia in adult Squints 33-35 EC Pemberton Some notes on treatment of abnormal retinal correspondence 36-37 B.Hare Convergence
    [Show full text]
  • Chromostereo.Pdf
    ChromoStereoscopic Rendering for Trichromatic Displays Le¨ıla Schemali1;2 Elmar Eisemann3 1Telecom ParisTech CNRS LTCI 2XtremViz 3Delft University of Technology Figure 1: ChromaDepth R glasses act like a prism that disperses incoming light and induces a differing depth perception for different light wavelengths. As most displays are limited to mixing three primaries (RGB), the depth effect can be significantly reduced, when using the usual mapping of depth to hue. Our red to white to blue mapping and shading cues achieve a significant improvement. Abstract The chromostereopsis phenomenom leads to a differing depth per- ception of different color hues, e.g., red is perceived slightly in front of blue. In chromostereoscopic rendering 2D images are produced that encode depth in color. While the natural chromostereopsis of our human visual system is rather low, it can be enhanced via ChromaDepth R glasses, which induce chromatic aberrations in one Figure 2: Chromostereopsis can be due to: (a) longitunal chro- eye by refracting light of different wavelengths differently, hereby matic aberration, focus of blue shifts forward with respect to red, offsetting the projected position slightly in one eye. Although, it or (b) transverse chromatic aberration, blue shifts further toward might seem natural to map depth linearly to hue, which was also the the nasal part of the retina than red. (c) Shift in position leads to a basis of previous solutions, we demonstrate that such a mapping re- depth impression. duces the stereoscopic effect when using standard trichromatic dis- plays or printing systems. We propose an algorithm, which enables an improved stereoscopic experience with reduced artifacts.
    [Show full text]
  • How Does Binocular Rivalry Emerge from Cortical
    HOW DOES BINOCULAR RIVALRY EMERGE FROM CORTICAL MECHANISMS OF 3-D VISION? Stephen Grossberg, Arash Yazdanbakhsh, Yongqiang Cao, and Guru Swaminathan1 Department of Cognitive and Neural Systems and Center for Adaptive Systems Boston University 677 Beacon Street, Boston, MA 02215 Phone: 617-353-7858 Fax: 617-353-7755 Submitted: July, 2007 Technical Report CAS/CNS-2007-010 All correspondence should be addressed to Professor Stephen Grossberg Department of Cognitive and Neural Systems Boston University 677 Beacon Street Boston, MA 02215 Phone: 617-353-7858/7857 Fax: 617-353-7755 Email:[email protected] 1 SG was supported in part by the National Science Foundation (NSF SBE-0354378) and the office of Naval Research (ONR N00014-01-1-0624). AY was supported in part by the Air Force Office of Scientific Research (AFOSR F49620-01-1-0397) and the Office of Naval Research (ONR N00014-01-1-0624). YC was supported by the National Science Foundation (NSF SBE-0354378). GS was supported in part by the Air Force Office of Scientific Research (AFOSR F49620-98-1-0108 and F49620-01-1-0397), the National Science Foundation (NSF IIS-97-20333), the Office of Naval Research (ONR N00014-95-1-0657, N00014- 95-1-0409, and N00014-01-1-0624), and the Whitaker Foundation (RG-99-0186). Abstract Under natural viewing conditions, a single depthful percept of the world is consciously seen. When dissimilar images are presented to corresponding regions of the two eyes, binocular rivalry may occur, during which the brain consciously perceives alternating percepts through time. How do the same brain mechanisms that generate a single depthful percept of the world also cause perceptual bistability, notably binocular rivalry? What properties of brain representations correspond to consciously seen percepts? A laminar cortical model of how cortical areas V1, V2, and V4 generate depthful percepts is developed to explain and quantitatively simulate binocular rivalry data.
    [Show full text]
  • Depth Inversion Despite Stereopsis: the Appearance of Random-Dot Stereograms on Surfaces Seen in Reverse Perspective
    Perception, 1979, volume 8, pages 135-142 Depth inversion despite stereopsis: the appearance of random-dot stereograms on surfaces seen in reverse perspective John I Yellott, Jr, Jerry L Kaiwi Cognitive Science Group, School of Social Sciences, University of California at Irvine, Irvine, California 92717, USA Received 20 October 1977, in revised form 18 October 1978 Abstract. Inside-out relief masks of faces can be depth-inverted (i.e. seen in reverse perspective) during close-up binocular viewing. If a random-dot stereogram is projected onto such a mask, stereopsis can be achieved for the stereogram, and its depth planes are correctly seen while the mask itself, including the region covered by the stereogram, is simultaneously perceived as depth- inverted. This demonstration shows that binocular depth inversion cannot be explained by a complete loss of stereoscopic information (e.g. through monocular suppression), or by a process analogous to pseudoscopic viewing whereby retinal disparities are incorporated into perception, but with their signs uniformly reversed. 1 Introduction Reversible perspective is probably most often thought of in connection with ambiguous pictures like the Necker cube (figure la), but it is also well-known that depth reversals can sometimes be experienced with solid objects, and with far more dramatic perceptual consequences. [Gregory (1970) describes these in detail; Helmholtz (1925) reviews references back to 1712, and Hochberg (1972) and Robinson (1972) review the modern literature, which is surprisingly thin.] In this note we use 'depth inversion' to refer specifically to this second kind of reversible perspective, in which real objects (rather than depicted ones) are perceived, from the standpoint of depth, as inside-out, so that their concave surfaces appear convex and vice versa.
    [Show full text]
  • A Survey of 3DTV Displays: Techniques and Technologies
    IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 17, NO. 11, NOVEMBER 2007 1647 A Survey of 3DTV Displays: Techniques and Technologies Philip Benzie, Member, IEEE, John Watson, Senior Member, IEEE, Phil Surman, Ismo Rakkolainen, Klaus Hopf, Hakan Urey, Member, IEEE, Ventseslav Sainov, and Christoph von Kopylow (Invited Paper) Abstract—The display is the last component in a chain of ac- both vertical and horizontal parallax and several viewers are able tivity from image acquisition, compression, coding transmission to see a 3-D image that exhibits no accommodation/convergence and reproduction of 3-D images through to the display itself. rivalry. However, the principal disadvantages of these displays There are various schemes for 3-D display taxonomy; the basic are: the images are generally transparent, the hardware tends categories adopted for this paper are: holography where the image to be complex and non-Lambertian intensity distribution cannot is produced by wavefront reconstruction, volumetric where the be displayed. Multiple image displays take many forms and it is image is produced within a volume of space and multiple image likely that one or more of these will provide the solution(s) for the displays where two or more images are seen across the viewing first generation of 3DTV displays. field. In an ideal world a stereoscopic display would produce Index Terms—Holography, TV, 3-D displays. images in real time that exhibit all the characteristics of the original scene. This would require the wavefront to be reproduced accurately, but currently this can only be achieved using holo- graphic techniques. Volumetric displays provide both vertical and I.
    [Show full text]
  • Course Notes
    Siggraph ‘97 Stereo Computer Graphics for Virtual Reality Course Notes Lou Harrison David McAllister Martin Dulberg Multimedia Lab Department of Computer Science North Carolina State University ACM SIGGRAPH '97 Stereoscopic Computer Graphics for Virtual Reality David McAllister Lou Harrison Martin Dulberg MULTIMEDIA LAB COMPUTER SCIENCE DEPARTMENT NORTH CAROLINA STATE UNIVERSITY http://www.multimedia.ncsu.edu Multimedia Lab @ NC State Welcome & Overview • Introduction to depth perception & stereo graphics terminology • Methods to generate stereoscopic images • Stereo input/output techniques including head mounted displays • Algorithms in stereoscopic computer graphics Multimedia Lab @ NC State Speaker Biographies: David F. McAllister received his BS in mathematics from the University of North Carolina at Chapel Hill in 1963. Following service in the military, he attended Purdue University, where he received his MS in mathematics in 1967. He received his Ph. D. in Computer Science in 1972 from the University of North Carolina at Chapel Hill. Dr. McAllister is a professor in the Department of Computer Science at North Carolina State University. He has published many papers in the areas of 3D technology and computer graphics and has given several courses in these areas at SPIE, SPSE, Visualization and SIGGRAPH. He is the editor of a book on Stereo Computer Graphics published by Princeton University Press. Lou Harrison received his BS in Computer Science from North Carolina State University in 1987 and his MS in Computer Science, also from NCSU, in 1990. Mr. Harrison has taught courses in Operating Systems and Computer Graphics at NCSU and is currently Manager of Operations for the Department of Computer Science at NCSU while pursuing his Ph.
    [Show full text]
  • A Primer on Binocular Rivalry, Including Current Controversies
    A Primer on Binocular Rivalry, Including Current Controversies Randolph Blake Vanderbilt Vision Research Center Vanderbilt University Nashville TN 37240 USA running head: Binocular Rivalry email: [email protected] voice: 615-343-7010 FAX: 615-343-5029 Binocular Rivalry Abstract. Among psychologists and vision scientists, binocular rivalry has enjoyed sustained interest for decades dating back to the 19th century. In recent years, however, rivalry’s audience has expanded to include neuroscientists who envision rivalry as a “tool” for exploring the neural concomitants of conscious visual awareness and perceptual organization. For rivalry’s potential to be realized, workers using this “tool” need to know details of this fascinating phenomenon, and providing those details is the purpose of this article. After placing rivalry in a historical context, I summarize major findings concerning the spatial characteristics and the temporal dynamics of rivalry, discuss two major theoretical accounts of rivalry (“eye” vs “stimulus” rivalry) and speculate on possible neural concomitants of binocular rivalry. key words: binocular rivalry, suppression, conscious awareness, neural model, perceptual organization 1. Introduction The human brain has been touted as the most complex structure in the known universe (Thompson, 1985). This may be true, but despite its awesome powers the brain can behave like a confused adolescent when it is confronted with conflicting visual messages. When dissimilar visual stimuli are imaged on corresponding retinal regions of the two eyes, the brain lapses into an unstable state characterized by alternating periods of perceptual dominance during which one visual stimulus or the other is seen at a time. This confusion is understandable, for the eyes are signalling the brain that two different objects exist at the same location in space at the same time.
    [Show full text]
  • Towards Quantifying Depth and Size Perception in Virtual
    Jannick P. Rolland Towards and Quantifying Depth William Gibson and Size Perception in Virtual Department of Computer Science, Environments CB3I75 University of North Carolina Chapel Hill, North Carolina 27599 Dan Ariely Department of Psychology, CB 3270 Abstract University of North Carolina Chapel Hill, North Carolina 27599 With the rapid advance of real-time computer graphics, head-mounted displays (HMDs) have become popular tools for 3D visualization. One of the most promising and chal- lenging future uses of HMDs, however, is in applications where virtual environments enhance rather than replace real environments. In such applications, a virtual ¡mage is superimposed on a real image. The unique problem raised by this superimposition is the difficulty that the human visual system may have in integrating information from these two environments. As a starting point to studying the problem of information integration in see-through environments, we investigate the quantification of depth and size perception of virtual objects relative to real objects in combined real and virtual environments. This starting point leads directly to the important issue of system calibra- tion, which must be completed before perceived depth and sizes are measured. Finally, preliminary experimental results on the perceived depth of spatially nonoverlapping real and virtual objects are presented. I Introduction Head-mounted displays (HMDs) have become popular tools for 3D visu- alization following the rapid advance of real-time computer graphics. They pro- vide 3D information to the user by presenting stereoscopic images to his eyes, similar to a simple slide stereoscope. The main difference is that the two images are scanned on two head-mounted miniature displays and can be updated in real time using fast computer graphics.
    [Show full text]
  • Durham E-Theses
    Durham E-Theses Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study FRONER, BARBARA How to cite: FRONER, BARBARA (2011) Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/3324/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study by Barbara Froner A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy School of Engineering and Computing Sciences Durham University United Kingdom Copyright °c 2011 by Barbara Froner Abstract Stereoscopic 3D Technologies for Accurate Depth Tasks: A Theoretical and Empirical Study Barbara Froner In the last decade an increasing number of application ¯elds, including medicine, geoscience and bio-chemistry, have expressed a need to visualise and interact with data that are inherently three-dimensional.
    [Show full text]