Thesis (M.Sc.)--York University, 2004. Graduate Programme in Earth and Space Science & Engineering. / Typescript. Includes bibliographical references (leaves 117-123). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11920

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 202-221). Also available on the Internet.

Thesis (MScEng)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: We present all the components needed for a fully-fledged stereo vision system, ranging from object detection through camera calibration to depth perception. We propose an efficient, automatic and practical method to calibrate cameras for use in 3D machine vision metrology. We develop an automated stereo calibration system that only requires a series of views of a manufactured calibration object in unknown positions. The system is tested against real and synthetic data, and we investigate the robustness of the proposed method compared to standard calibration practice. All the aspects of 3D stereo reconstruction is dealt with and we present the necessary algorithms to perform epipolar rectification on images as well as solving the correspondence and triangulation problems. It was found that the system performs well even in the presence of noise, and calibration is easy and requires no specialist knowledge. / AFRIKAANSE OPSOMMING: Ons beskryf al die komponente van 'n omvattende stereo visie sisteem. Die kern van die sisteem is 'n effektiewe, ge-outomatiseerde en praktiese metode om kameras te kalibreer vir gebruik in 3D rekenaarvisie. Ons ontwikkel 'n outomatiese, stereo kamerakalibrasie sisteem wat slegs 'n reeks beelde van 'n kalibrasie voorwerp in onbekende posisies vereis. Die sisteem word getoets met reële en sintetiese data, en ons vergelyk die robuustheid van die metode met die standaard algoritmes. Al die aspekte van die 3D stereo rekonstruksie word behandel en ons beskryf die nodige algoritmes om epipolêre rektifikasie op beelde te doen sowel as metodes om die korrespondensie- en diepte probleme op te los. Ons wys dat die sisteem goeie resultate lewer in die aanwesigheid van ruis en dat kamerakalibrasie outomaties kan geskied sonder dat enige spesialis kennis benodig word.

M.Sc. / The domain of computer graphics has undergone phenomenal changes and improvements over the past decade, to the extent that photorealistic renderings have now become possible. Evidence of the vast potential of such renderings is all too clear in movies such as The Titanic. In the manufacturing arena, however, it is rarely required to produce visualisations of this quality. The rendered image is, in fact, required merely to visualise the required data set effectively and unambiguously, a requirement that can be met without reverting to the latest rendering algorithms. What is considered more important, however, is the functionality that has become available to the user. Virtual-reality-type interfaces and displays, real-time object manipulation and interactive measuring utilities are but a few functions required effectively to reduce costs during the design phase of a project. Although handy, the latter functions serves exponentially to multiply the processing requirements of the underlying hardware platform. In order, therefore, to ensure that interactiveness be maintained, some rendering techniques may have to be omitted so as to render the visualised scene unambiguously. Traditionally, visualisations required specialised graphics workstations. Although this requirement still obtains to medium- and large-scale visualisations, the PC industry has seen a dramatic increase in computing power, to the extent that it might be possible to implement small-scale visualisations at PC level soon. DirectX constitutes a set of graphics libraries developed by Microsoft as a standard for game developers and video accelerator manufacturers. Although DirectX has very rarely been implemented in a non-gaming environment, it is possible through the use of effects such as texture mapping and Gourad shading, which effects are supported by DirectX, to create a small-scale visualisation of acceptable rendering quality. If this could be achieved, companies could use their existing computers to implement visualisations of this kind. In so doing, visualisation capabilities would be made available to a much bigger segment of the market.

The quality control of geometrical coherences and relations in modern automobile production is done by different stationary and flexible measurement systems and strategies. Furthermore, there currently exists possibilities of inline measurements and offline measurements. This project presents the basic research concerning the possibility of a flexible wireless measurement system in modern automobile production, that is able to combine the advantages of both strategies. An investigation of existing measurement techniques was done in order to find a sensor technology, which enables the wireless measurement process. The research project introduces the current location systems and positioning systems. These techniques are compared by a value benefit analysis to expose a suited technology as basis for the measurement system. As result of the value benefit anlysis, the ultrasonic technique was selected for further investigations. The ultrasonic test setup is used to analyze the accuracy of modern sensors and to verify the possibility of a project related integration. The tests are done in different conditions, in order to compare the laboratory application and the industrial application. During the test measurements different physical influencing variables and disturbances occurred. From this research project, it can be concluded that the laboratory application of the system is possible. However, the industrial application is subject to restrictions.

The recent transformation of consumer graphics (CG) cards into powerful 3D rendering processors is due in large measure to the success of game developers in delivering mass market entertainment software that feature highly immersive and captivating virtual environments. Despite this success, 3D CG application development is becoming increasingly handicapped by the inability of traditional content creation methods to keep up with the demand for content. The term content is used here to refer to any data operated on by application code that is meant for viewing, including 3D models, textures, animation sequences and maps or other data-intensive descriptions of virtual environments. Traditionally, content has been handcrafted by humans. A serious problem facing the interactive graphics software development community is how to increase the rate at which content can be produced to keep up with the increasingly rapid pace at which software for interactive applications can now be developed. Research addressing this problem centers around procedural content creation systems. By moving away from purely human content creation toward systems in which humans play a substantially less time-intensive but no less creative part in the process, procedural content creation opens new doors. From a qualitative standpoint, these types of systems will not rely less on human intervention but rather more since they will depend heavily on direction from a human in order to synthesize the desired content. This research draws heavily from the entertainment software domain but the research is broadly relevant to 3D graphics applications in general.

The design of autonomous agents capable of performing a given goal in a 3D domain continues to be a challenge for computer animated story generation systems. We present a novel prototype which consists of a 3D engine and a planner for a simple virtual world. We incorporate the 2D planner into the 3D engine to provide 3D animations. Based on the plan, the 3D world is created and the objects are positioned. Then the plan is linearized into simpler actions for object animation and rendered via the 3D engine. We use JINNI3D as the engine and WARPLAN-C as the planner for the above-mentioned prototype. The user can interact with the system using a simple natural language interface. The interface consists of a shallow parser, which is capable of identifying a set of predefined basic commands. The command given by the user is considered as the goal for the planner. The resulting plan is created and rendered in 3D. The overall system is comparable to a character based interactive story generation system except that it is limited to the predefined 3D environment.

No description available.

Current interest in three-dimensional (3-D) information displays has focused on the use of field-sequential CRT techniques to present binocular stereoscopic images. Although it is widely believed that stereopsis provides a potent depth information cue, numerous monocular cues exist which may augment, detract from, or even supplant stereopsis. Unfortunately, few guidelines or well-controlled analyses on the use of depth cues are available to direct engineering implementations of stereoscopic display systems. This dissertation describes three experiments using 3-D images presented on a Tektronix SGS 620 field-sequential stereoscopic CRT (19-inch diagonal, 120-Hz field rate, passive glasses). In the first experiment, 10 participants with normal vision judged the relative apparent depth ordering of three simple geometric figures (planar circle, square, and triangle). Four sources of depth information (cue types) were factorially combined to construct exemplary images of planar figures in apparent depth: Relative Size (angular subtense decreased with increasing apparent depth); Disparity (binocular disparity varied from crossed to uncrossed with increasing apparent depth); Interposition (closer figures partially occluded ones farther away in apparent depth); and Luminance (luminance decreased with increasing apparent depth). The three monocular cues (Interposition, Size, and Luminance) produced significantly faster depth judgments when used alone; however, when used in combination, Interposition dominated the response time data trends. Although the Disparity cue received moderately high "perceived effectiveness" ratings, response time measures indicated that it played a minor role in the relative depth judgment task. The second experiment was conducted to investigate further the subjective value of the various depth cues. Participants rated subjective image quality (quality of depth) rather than making rapid relative depth judgements. As anticipated, the most satisfactory ratings of depth were made for display images which included stereoscopic depth (Disparity), with the very highest ratings given to display images which included all four depth cues. The results of these first two experiments illustrated a task-demand (objective vs. subjective) discrepancy in the utility of stereoscopic depth cues. The third experiment extended the initial work to include more geometrically complex stimuli in visual search and cursor positioning tasks. In these task environments, stereoscopic disparity and monocular depth cues had an interactive effect on improving visual search times and reducing cursor positioning errors on the depth axis, with the best performance associated with the presence of all depth cues. The complementary nature of these effects was attenuated when depth cue salience was elevated to suprathreshold levels. Based on the results of this research, recommendations are presented for the display of depth information with the stereoscopic CRT. The importance of this research is underscored by the fact that while technological advances have been made in the field of stereoscopic display, very few usability data exist either from laboratory testing or from the implementation of such displays in operational systems. This research provides information to complete cost/performance benefit analyses for 3-D display designs which could in turn significantly impact industry acceptance of the field-sequential stereoscopic CRT. / Ph. D.

The purpose of this study is to model the beam/decking connectors (nails) of a glulam dome cap by beam/connector elements, and to analyze various dome cap models in order to investigate the potential of the beam/connector model to simulate the decking. Two- and three-dimensional beam/connector elements are formulated, tested, and evaluated. The dome cap is modeled with I-DEAS, and the modeling procedures are briefly discussed. Four series of beam/connector dome cap models are created and analyzed: (1) models with the nailed joints at bracing points (rigid link h=0), (2) models with the nailed joints at bracing points (h>0), (3) models with 16 nailed joints per beam element (h=0), and (4) models with 16 nailed joints per beam element (h>0). Their results are compared with the dome cap models with the truss bracings. Finally, conclusions and recommendations for future research are presented. / Master of Science