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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluation of a Holographic 3D Display

Björk, Jim January 2010 (has links)
An autostereoscopic display based on a Holographic Optical Element(HOE) presents new opportunities for faithful 3D displaying but also presents potential new problems, such as: accuracy of 3D objects, interactivity and user perception. In this evaluation, which is the first of its kind for this type of display, I have explored and tested methods and tools for the evaluation of these potential problems. I have found that the visual quality is comparable to more common display types but with a significant visual delay due to the parallel rendering of graphics and the projectors significant input lag. From this I have concluded that the display system is not yet ready for its intended purpose, cranio-maxillofacial surgery planning. We need projectors with less input lag and preferably better optics. The software needs to be optimized for multimonitor rendering as well.
2

Investigation of the Effects of an Autostereographic Virtual Environment on Recall in Participants of Differing Levels of Field Dependence

Moore, Michael Wilson 14 April 2006 (has links)
Stereographic virtual environments display data in such a way that a user perceives objects within the displayed environment to be separated in depth from the display itself. The effectiveness of stereographic virtual environments as learning tools has been evaluated relative to factors such as multidimensional cues, user interaction, and learner characteristics. This study has examined the relationship between two evaluative factors: the presence of stereographic depth cues and field dependence, a learner characteristic associated with performance on visual tasks. Adult learners were identified on a field dependence continuum based on scores on the Group Embedded Figures Test. Each student received instruction related to the heart using stereographic materials or nonstereographic materials, depending on assignment to treatment group. All participants were given two tests, identification and terminology, following this instruction. The scores on the combination of these tests, denoted as the Modified Total Criterion Test (MTCT), represented the level of visual recall relative to the instructional materials reviewed. Analyses of variance revealed an interaction effect between the level of field dependence and the presence of stereographic depth cues within a virtual environment such that field independent participants scored higher on tests of visual recall within stereographic conditions versus nonstereographic conditions and field dependent participants scored lower within stereographic conditions versus nonstereographic conditions. / Ph. D.
3

Angle Perception On Autostereoscopic Displays

Karaman, Ersin 01 July 2009 (has links) (PDF)
Stereoscopic displays provide 3D vision usually with the help of additional equipment such as shutter glasses and head gears. As a new stereoscopic display technology, autostereoscopic 3D Displays provide 3D vision without additional equipment. Previous studies of depth and distance estimation with autostereoscopic displays indicate the users do not exhibit better performance in 3D. Yet, they claim 3D displays provide higher immersiveness. In this study, perception of the angle of a 3D shape is investigated by comparing 2D, 3D and Real perception cases. An experiment is conducted using an autostereoscopic 3D display. Forty people have participated in the experiment. They were asked to estimate the vertex angle and draw the projections of the object from two different viewpoints. It is found that users can better estimate the angles on a cone when viewed from the top on an autostereoscopic display. This may contribute positively to 3D understanding of the scene. Results revealed that participants make more accurate angle estimation in autostereoscopic 3D displays than in traditional 2D displays. In general, the participants&rsquo / angle drawings were slightly higher than their angle estimations. Moreover, the participants overestimated 35, 65 and 90 degree angles and underestimated 115 degree angle in autostereoscopic 3D display.
4

Zpracování stereoskopické videosekvence / Processing of Stereoscopic Video Sequence

Hasmanda, Martin January 2010 (has links)
The main goal of this master’s thesis was get up used methods for observation the stereoscopic scene with one couple of cameras and find out good solving for processing these resulting pictures for two-view and multiple-view autostereoscopic displays for three-dimensional perception. For methods for acquisition video was introduced two methods. They were method “Off-axis” with parallel camera axis and method “Toe in” with intersections axis. For fit method was choice the method named as “Off-axis“. It was not produces the vertical parallax and in detail was in this work described principle of this method. Further were describe principles off used methods for three-dimensional perception namely from the oldest method named anaglyph after methods for viewing at autostereoscopic displays. The Autostereoscopic displays were main goal of this thesis and so their principles were described in details. For production the result image for autostereoscopic displays was used generation intermediate images between left and right camera. Resulting videos were acquisition for testing scene in created in 3D studio Blender, where was possible setting system of cameras exactly parallel axis. Then were introduce principles processing video where was extract from the couple of cameras where were connected to PC for help digitizing card and next time with two web cameras. Here is not guaranteed exact parallel axis system. Therefore this work try for real cameras achieve exactly parallel axis system by the help of transformations of frames with stereo rectification. Stereo rectification was solving with OpenCV libraries and was used two methods. Both methods work from principles epipolar geometry that was described in this work also in detail. First method rectifies pictures on the basis fundamental matrix and found correspondences points in two images of the scene and second method rectifies pictures from knowledge intrinsic and extrinsic parameters of stereoscopic system of cameras. In the end of this work was described application for implementation introduced methods.

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