Impact of 3D Technologies and Environment Stimuli on Stereo Vision Perception Di Zhang
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Management of Microtropia
Br J Ophthalmol: first published as 10.1136/bjo.58.3.281 on 1 March 1974. Downloaded from Brit. J. Ophthal. (I974) 58, 28 I Management of microtropia J. LANG Zirich, Switzerland Microtropia or microstrabismus may be briefly described as a manifest strabismus of less than 50 with harmonious anomalous correspondence. Three forms can be distinguished: primary constant, primary decompensating, and secondary. There are three situations in which the ophthalmologist may be confronted with micro- tropia: (i) Amblyopia without strabismus; (2) Hereditary and familial strabismus; (3) Residual strabismus after surgery. This may be called secondary microtropia, for everyone will admit that in most cases of convergent strabismus perfect parallelism and bifoveal fixation are not achieved even after expert treatment. Microtropia and similar conditions were not mentioned by such well-known early copyright. practitioners as Javal, Worth, Duane, and Bielschowsky. The views of Maddox (i898), that very small angles were extremely rare, and that the natural tendency to fusion was much too strong to allow small angles to exist, appear to be typical. The first to mention small residual angles was Pugh (I936), who wrote: "A patient with monocular squint who has been trained to have equal vision in each eye and full stereoscopic vision with good amplitude of fusion may in 3 months relapse into a slight deviation http://bjo.bmj.com/ in the weaker eye and the vision retrogresses". Similar observations of small residual angles have been made by Swan, Kirschberg, Jampolsky, Gittoes-Davis, Cashell, Lyle, Broadman, and Gortz. There has been much discussion in both the British Orthoptic Journal and the American Orthoptic journal on the cause of this condition and ways of avoiding it. -
Specific Eye Conditions with Corresponding Adaptations/Considerations
Specific Eye Conditions with Corresponding Adaptations/Considerations # Eye Condition Effect on Vision Adaptations/Considerations 1 Achromotopsia colors are seen as shades of grey, tinted lenses, reduced lighting, alternative nystagmus and photophobia improve techniques for teaching colors will be with age required 2 Albinism decreased visual acuity, photophobia, sunglasses, visor or cap with a brim, nystagmus, central scotomas, strabismus reduced depth perception, moving close to objects 3 Aniridia photophobia, field loss, vision may tinted lenses, sunglasses, visor or cap with fluctuate depending on lighting brim, dim lighting, extra time required to conditions and glare adapt to lighting changes 4 Aphakia reduced depth perception, inability to sunglasses, visor or cap with a brim may accommodate to lighting changes be worn indoors, extra time required to adapt to lighting changes 5 Cataracts poor color vision, photophobia, visual bright lighting may be a problem, low acuity fluctuates according to light lighting may be preferred, extra time required to adapt to lighting changes 6 Colobomas photophobia, nystagmus, field loss, sunglasses, visor or cap with a brim, reduced depth perception reduced depth perception, good contrast required 7 Color Blindness difficulty or inability to see colors and sunglasses, visor or cap with a brim, detail, photophobia, central field reduced depth perception, good contrast scotomas (spotty vision), normal required, low lighting may be preferred, peripheral fields alternative techniques for teaching colors -
Stereoscopic Vision, Stereoscope, Selection of Stereo Pair and Its Orientation
International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Impact Factor (2012): 3.358 Stereoscopic Vision, Stereoscope, Selection of Stereo Pair and Its Orientation Sunita Devi Research Associate, Haryana Space Application Centre (HARSAC), Department of Science & Technology, Government of Haryana, CCS HAU Campus, Hisar – 125 004, India , Abstract: Stereoscope is to deflect normally converging lines of sight, so that each eye views a different image. For deriving maximum benefit from photographs they are normally studied stereoscopically. Instruments in use today for three dimensional studies of aerial photographs. If instead of looking at the original scene, we observe photos of that scene taken from two different viewpoints, we can under suitable conditions, obtain a three dimensional impression from the two dimensional photos. This impression may be very similar to the impression given by the original scene, but in practice this is rarely so. A pair of photograph taken from two cameras station but covering some common area constitutes and stereoscopic pair which when viewed in a certain manner gives an impression as if a three dimensional model of the common area is being seen. Keywords: Remote Sensing (RS), Aerial Photograph, Pocket or Lens Stereoscope, Mirror Stereoscope. Stereopair, Stere. pair’s orientation 1. Introduction characteristics. Two eyes must see two images, which are only slightly different in angle of view, orientation, colour, A stereoscope is a device for viewing a stereoscopic pair of brightness, shape and size. (Figure: 1) Human eyes, fixed on separate images, depicting left-eye and right-eye views of same object provide two points of observation which are the same scene, as a single three-dimensional image. -
Scalable Multi-View Stereo Camera Array for Real World Real-Time Image Capture and Three-Dimensional Displays
Scalable Multi-view Stereo Camera Array for Real World Real-Time Image Capture and Three-Dimensional Displays Samuel L. Hill B.S. Imaging and Photographic Technology Rochester Institute of Technology, 2000 M.S. Optical Sciences University of Arizona, 2002 Submitted to the Program in Media Arts and Sciences, School of Architecture and Planning in Partial Fulfillment of the Requirements for the Degree of Master of Science in Media Arts and Sciences at the Massachusetts Institute of Technology June 2004 © 2004 Massachusetts Institute of Technology. All Rights Reserved. Signature of Author:<_- Samuel L. Hill Program irlg edia Arts and Sciences May 2004 Certified by: / Dr. V. Michael Bove Jr. Principal Research Scientist Program in Media Arts and Sciences ZA Thesis Supervisor Accepted by: Andrew Lippman Chairperson Department Committee on Graduate Students MASSACHUSETTS INSTITUTE OF TECHNOLOGY Program in Media Arts and Sciences JUN 172 ROTCH LIBRARIES Scalable Multi-view Stereo Camera Array for Real World Real-Time Image Capture and Three-Dimensional Displays Samuel L. Hill Submitted to the Program in Media Arts and Sciences School of Architecture and Planning on May 7, 2004 in Partial Fulfillment of the Requirements for the Degree of Master of Science in Media Arts and Sciences Abstract The number of three-dimensional displays available is escalating and yet the capturing devices for multiple view content are focused on either single camera precision rigs that are limited to stationary objects or the use of synthetically created animations. In this work we will use the existence of inexpensive digital CMOS cameras to explore a multi- image capture paradigm and the gathering of real world real-time data of active and static scenes. -
Effects on Visibility and Lens Accommodation of Stereoscopic Vision Induced by HMD Parallax Images
Original Paper Forma, 29, S65–S70, 2014 Effects on Visibility and Lens Accommodation of Stereoscopic Vision Induced by HMD Parallax Images Akira Hasegawa1,2∗, Satoshi Hasegawa3, Masako Omori4, Hiroki Takada5,Tomoyuki Watanabe6 and Masaru Miyao1 1Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan 2Library Information Center, Nagoya Bunri University, 365 Maeda, Inazawa-cho, Inazawa 492-8520, Japan 3Department of Information and Media Studies, Nagoya Bunri University, 365 Maeda, Inazawa-cho, Inazawa 492-8520, Japan 4Faculty of Home Economics, Kobe Women’s University, Suma-ku, Kobe 654-8585, Japan 5Department of Human and Artificial Intelligent Systems, Graduate School of Engineering, University of Fukui, Fukui 910-8507, Japan 6Department of Nutritional Science, Faculty of Psychological and Physical Science, Aichi Gakuin University, Nisshin 470-0195, Japan ∗E-mail address: [email protected] (Received October 31, 2010; Accepted April 22, 2011) The visual function of lens accommodation was measured while subjects used stereoscopic vision with a head mounted display (HMD). Eyesight while viewing stereoscopic Landolt ring images displayed on HMD was also studied. Accommodation to virtual objects was seen when subjects viewed stereoscopic images of 3D computer graphics, but not when the images were displayed without appropriate binocular parallax. This suggests that stereoscopic moving images on HMD induced visual accommodation. Accommodation should be adjusted to the position of virtual stereoscopic images induced by parallax. A difference in the distances of the focused display and stereoscopic image may cause visual load. However, an experiment showed that Landolt rings of almost the same size were distinguished regardless of virtual distance of 3D images if the parallax was not larger than the fusional upper limit. -
Routine Eye Examination
CET Continuing education Routine eye examination Part 3 – Binocular assessment In the third part of our series on the eye examination, Andrew Franklin and Bill Harvey look at the assessment and interpretation of binocular status. Module C8290, one general CET point, suitable for optometrists and DOs he assessment of binocular previous question. Leading questions function is often one of the should be avoided, especially when weaker areas of a routine, dealing with children. If they are out if observation of candidates of line ask the patient ‘Which one is out in the professional qualifica- of line with the X?’ Ttions examination is any guide. Tests are You should know before you start the done for no clearly logical reason, often test which line is seen by which eye. because they always have been, and in If you cannot remember it from last an order which defeats the object of the time, simply look at the target through testing. Binocular vision seems to be one the visor yourself (Figure 1). Even if of those areas that practitioners shy away you think you can remember, check from, and students often take an instant anyway, as it is possible for the polarisa- dislike to. Many retests and subsequent tion of the visor not to match that of the remakes of spectacles are the result of a Mallett Unit at distance or near or both, practitioner overlooking the effects of a Figure 1 A distance fixation disparity target especially if the visor is a replacement. change of prescription on the binocular If both eyes can see both bars, nobody status of the patient. -
Teacher Guide
Neuroscience for Kids http://faculty.washington.edu/chudler/neurok.html. Our Sense of Sight: Part 2. Perceiving motion, form, and depth Visual Puzzles Featuring a “Class Experiment” and “Try Your Own Experiment” Teacher Guide WHAT STUDENTS WILL DO · TEST their depth perception using one eye and then two · CALCULATE the class averages for the test perception tests · DISCUSS the functions of depth perception · DEFINE binocular vision · IDENTIFY monocular cues for depth · DESIGN and CONDUCT further experiments on visual perception, for example: · TEST people’s ability to interpret visual illusions · CONSTRUCT and test new visual illusions · DEVISE a “minimum difference test” for visual attention 1 SETTING UP THE LAB Supplies For the Introductory Activity Two pencils or pens for each student For the Class Experiment For each group of four (or other number) students: Measuring tools (cloth tape or meter sticks) Plastic cups, beakers or other sturdy containers Small objects such as clothespins, small legos, paper clips For “Try Your Own Experiment!” Visual illusion figures, found at the end of this Teacher Guide Paper and markers or pens Rulers Other Preparations · For the Class Experiment and Do Your Own Experiment, students can write results on a plain sheet of paper. · Construct a chart on the board where data can be entered for class discussion. · Decide the size of the student groups; three is a convenient number for these experiments—a Subject, a Tester, and a Recorder. Depending on materials available, four or five students can comprise a group. · For “Try Your Own Experiment!,” prepare materials in the Supply list and put them out on an “Explore” table. -
The Effect of the Fixation Disparity on Photogrammetric Processes
The Effect of the Fixation Disparity on Photogrammetric Processes SANDOR A. VERES, Asst. Proj., Surveying and Mapping, Purdue University ABSTRACT: This paper reviews the function oj the human eyes in photogram metry, and discusses its limitations. The correction of the observation error is presented by mathematical derivations and practical examples. The paper points out the need for continued development of techniques in view of con stantly increasing requirements. INTRODUCTION study of coincidence is most important from the photogrammetric point of view. For a HOTOGRAMMETRIC instrumentation has undergone a revolutionary development study of this kind an instrument called a P horopter has been used. since the second World War. A precision photogrammetric instrument today is able to The horopter designed by Tschermak con provide measurement to within a precision of sists of thirteen steel channels mounted so as ± 3 microns. By using these precision in to converge to the midpoint of the inter struments the compensation of errors in pupillary base line of the two eyes of an volved in the measurements becomes of pri observer. The central channel lies in a median mary importance. The compensation of errors plane, perpendicular to the eyebase of the is based upon the geometrical knowledge of observer, and the others make angles of 1, 2. the source of errors. The human eye is in 4, 8, 12, and 16 degrees on each side of the volved in every photogrammetric measure central channel. A small vertical steel rod can ment; consequently the geometrical knowl slide smoothly in each channel and the rods edge of the errors due to the limi tation of the are mounted for use at visual distances of 20, human eye is very important. -
The Nature, Testing, and Variables Influencing
THE NATURE, TESTING, AND VARIABLES INFLUENCING FIXATION DISPARITY; ROLE OF THE FUSION LOCK 1 by Leland W. Carr with Dr. James J. Saladin I ... *I Tl.e N.-1• .._1 Tufi"), A.l IJ.,.;.,l/.s I.{l..•• :? F1*'/:·.., /);,,_,. ; ~ R.lc. OF 'Tlc. ~="••1•.. C. •• l( I Introduction A fixation disparity is a small angular measurement of the mis alignment of the two eyes which can occur while still permitting single, fused binocular vision. It represents a small error in the aiming of the eyes which occurs without diplopia being detected. Fixation disparity is allowed because of the slight "slippage" pro vided to the fusional system through the existence of Panum's fusional areas. So long as binocular alignment is precise enough to place the two retinal images of a single object within corre sponding Panum's areas, the final perception is likely to be single and fused. Sensory fusion thus occurs in spite of a small error in motor fusion. A slight muscle imbalance is the rule, rather than the excep tion in individuals even with normal assymptomatic binocular systems. It is rare that all twelve extraocular muscles are precisely bal anced in their agonist-antagonist relationships, and thus the inate drive to achieve single vision requires a fusional effort to over come existing imbalance. When binocularity is dissociated (as with a covertest) the fusional drive is interrupted and the eyes deviate out of alignment under the influence of the muscle imbalance. This deviation under dissociation is referred to as the heterophoria. When both eyes are permitted to view without dissociative conditions the fusional drive to achieve single binocular vision pulls the eyes toward alignment in opposition to the phoric "stress" operating to deviate the alignment. -
Visual Secret Sharing Scheme with Autostereogram*
Visual Secret Sharing Scheme with Autostereogram* Feng Yi, Daoshun Wang** and Yiqi Dai Department of Computer Science and Technology, Tsinghua University, Beijing, 100084, China Abstract. Visual secret sharing scheme (VSSS) is a secret sharing method which decodes the secret by using the contrast ability of the human visual system. Autostereogram is a single two dimensional (2D) image which becomes a virtual three dimensional (3D) image when viewed with proper eye convergence or divergence. Combing the two technologies via human vision, this paper presents a new visual secret sharing scheme called (k, n)-VSSS with autostereogram. In the scheme, each of the shares is an autostereogram. Stacking any k shares, the secret image is recovered visually without any equipment, but no secret information is obtained with less than k shares. Keywords: visual secret sharing scheme; visual cryptography; autostereogram 1. Introduction In 1979, Blakely and Shamir[1-2] independently invented a secret sharing scheme to construct robust key management scheme. A secret sharing scheme is a method of sharing a secret among a group of participants. In 1994, Naor and Shamir[3] firstly introduced visual secret sharing * Supported by National Natural Science Foundation of China (No. 90304014) ** E-mail address: [email protected] (D.S.Wang) 1 scheme in Eurocrypt’94’’ and constructed (k, n)-threshold visual secret sharing scheme which conceals the original data in n images called shares. The original data can be recovered from the overlap of any at least k shares through the human vision without any knowledge of cryptography or cryptographic computations. With the development of the field, Droste[4] provided a new (k, n)-VSSS algorithm and introduced a model to construct the (n, n)-combinational threshold scheme. -
Stereoscopic Therapy: Fun Or Remedy?
STEREOSCOPIC THERAPY: FUN OR REMEDY? SARA RAPOSO Abstract (INDEPENDENT SCHOLAR , PORTUGAL ) Once the material of playful gatherings, stereoscop ic photographs of cities, the moon, landscapes and fashion scenes are now cherished collectors’ items that keep on inspiring new generations of enthusiasts. Nevertheless, for a stereoblind observer, a stereoscopic photograph will merely be two similar images placed side by side. The perspective created by stereoscop ic fusion can only be experienced by those who have binocular vision, or stereopsis. There are several caus es of a lack of stereopsis. They include eye disorders such as strabismus with double vision. Interestingly, stereoscopy can be used as a therapy for that con dition. This paper approaches this kind of therapy through the exploration of North American collections of stereoscopic charts that were used for diagnosis and training purposes until recently. Keywords. binocular vision; strabismus; amblyopia; ste- reoscopic therapy; optometry. 48 1. Binocular vision and stone (18021875), which “seem to have access to the visual system at the same stereopsis escaped the attention of every philos time and form a unitary visual impres opher and artist” allowed the invention sion. According to the suppression the Vision and the process of forming im of a “simple instrument” (Wheatstone, ory, both similar and dissimilar images ages, is an issue that has challenged 1838): the stereoscope. Using pictures from the two eyes engage in alternat the most curious minds from the time of as a tool for his study (Figure 1) and in ing suppression at a low level of visual Aristotle and Euclid to the present day. -
Visualization and Visual System Affect Spatial Performance in Augmented
Journal of Vision (2021) 21(8):17, 1–18 1 When virtual and real worlds coexist: Visualization and visual system affect spatial performance in augmented reality Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, Tatjana Pladere University of Latvia, Riga, Latvia Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, University of Latvia, Riga, Latvia Laboratory of Statistical Research and Data Analysis, Faculty of Physics, Mathematics and Optometry, Artis Luguzis University of Latvia, Riga, Latvia Roberts Zabels LightSpace Technologies, Marupe, Latvia Rendijs Smukulis LightSpace Technologies, Marupe, Latvia Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, Viktorija Barkovska University of Latvia, Riga, Latvia Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, Linda Krauze University of Latvia, Riga, Latvia Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, Vita Konosonoka University of Latvia, Riga, Latvia Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, Aiga Svede University of Latvia, Riga, Latvia Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, Gunta Krumina University of Latvia, Riga, Latvia New visualization approaches are being actively environment of augmented reality using a developed aiming to mitigate the effect of head-mounted display that was driven in multifocal and vergence-accommodation conflict in stereoscopic single focal plane modes. Participants matched the augmented reality; however, high interindividual distance of a real object with images projected at three variability in spatial performance makes it difficult to viewing distances, concordant with the display focal predict user gain.