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Background: The literature proposes several algorithms that produce “quality-controlled” stereoscopic depth in 3D films by limiting the stereoscopic depth to a defined depth budget. Like stereoscopic displays, spatial sound systems provide the listener with enhanced (auditory) depth cues, and are now commercially available in multiple forms. AIM: We investigate the implications of introducing auditory depth cues to quality-controlled 3D media, by asking: “Is it important to quality-control audio-visual depth by considering audio-visual interactions, when integrating stereoscopic display and spatial sound systems?” Motivation: There are several reports in literature of such “audio-visual interactions”, in which visual and auditory perception influence each other. We seek to answer our research question by investigating whether these audio-visual interactions could extend the depth budget used in quality-controlled 3D media. Method/Conclusions: The related literature is reviewed before presenting four novel experiments that build upon each other’s conclusions. In the first experiment, we show that content created with a stereoscopic depth budget creates measurable positive changes in audiences’ attitude towards 3D films. These changes are repeatable for different locations, displays and content. In the second experiment we calibrate an audio-visual display system and use it to measure the minimum audible depth difference. Our data is used to formulate recommendations for content designers and systems engineers. These recommendations include the design of an auditory depth perception screening test. We then show that an auditory-visual stimulus with a nearer auditory depth is perceived as nearer. We measure the impact of this effect upon a relative depth judgement, and investigate how the impact varies with audio-visual depth separation. Finally, the size of the cross-modal bias in depth is measured, from which we conclude that sound does have the potential to extend the depth budget by a small, but perceivable, amount.

This thesis is particularly concerned with everyday creativity as a social practice that is taking place within the digital environment. Web 2.0 made it much easier for laypersons to produce and publish digital content and to participate in online communities. Through participation community members can acquire domain-relevant knowledge as well as develop their digital competency. In some areas, online communities of highly motivated amateurs (Pro-Ams) work to professional standards and even achieve better results than their professional colleagues. Open Source software projects or Wikis are among areas that rely on committed amateurs and the strength of a community. The empirical stage of the research comprises two studies that aim to investigate the role of ICT and the Internet in everyday creative activities and how the use of digital tools for creativity can be facilitated and improved. An exploratory online survey revealed that the majority of participants are involved in everyday creative activities many of which are performed with the use of digital tools. However, the lack of digital competency and skills has been proved to be among the main barriers to using software tools for everyday creativity and participation in the digital environment. Taking into account the survey data that revealed digital photo-editing and manipulation to be the most popular creative activity among participants, a powerful, free, image-editing program - the GIMP - was chosen for the experiment. A group of people with no professional knowledge of using image editing programs participated in a single-day workshop where they learned how to do basic image processing with a free software editor, the GIMP. Data collection methods involved questionnaires, observation and follow-up telephone interviews. The GIMP tutorial and practice session proved to be successful in engaging non-professionals in image manipulation with the GIMP and facilitating further use and learning through individual effort.

This thesis addresses the problem of modeling human shape in three dimensions. Specifically, this thesis is focused on modeling body shape variation across multiple individuals, pose induced shape deformations and garment deformations that are influenced both by body shape and pose. A methodology for constructing data driven models of human body and garment deformation is provided. Additionally, an application for online fashion retailing is presented. Abstract Firstly, a quantitative and qualitative evaluation, is introduced, of surface representations used in recent statistical models of human shape and pose. It is shown that the Euclidean representation generates a more compact human shape model compared to other representations. A small number of model parameters indicates better convergence in a human body estimation framework. In contrast, a high number of model parameters increases the risk of the optimization getting trapped in a local optimum. Based on these insights a system for human body shape estimation and classification for on-line fashion applications is presented. Given a single image of a subject and the subject's height and weight the proposed framework is able to estimate the 3D human body shape using a learnt statistical model. Results demonstrate that a single image holds sufficient information for accurate shape classification. This technology has been exploited as part of a collaborative project with fashion designers to develop a mobile app to classify body shape for clothing recommendation in online fashion retail. Abstract Next, Shape and Pose Space Deformation (SPSD) is presented, a technique for modeling subject specific pose induced deformations. By exploiting examples of different people in multiple poses, plausible animations of novel subjects can be synthesized by interpolating and extrapolating in a joint shape and pose parameter space. The results show that greater detail is achieved by incorporating subject specific pose deformations as opposed to a subject independent pose model. Finally, SPSD is extended to a three layered data-driven model of human shape, pose and garment deformation. Each layer represents the deformation of a template mesh and can be controlled independently and intuitively. The garment deformation layer is trained on sequences of dressed actors and relies on a novel technique for human shape and posture estimation under clothing.

The Multi-Layered Displays (MLD) comprise two LCD screens mounted one in front of the other, allowing the presentation of information on both screens. This physical separation produces depth without requiring glasses. This research evaluated the utility of the MLD for change detection tasks, particularly in operational environments. Change Blindness refers to the failure to detect changes when the change happens during a visual disruption. The literature equates these visual disruptions with the types of interruptions that occur regularly in work situations. Change blindness is more likely to occur when operators monitor dynamic situations spread over several screens, when there are popup messages, and when there are frequent interruptions which are likely to block the visual transients that signal a change. Four laboratory experiments were conducted to evaluate the utility of the MLD for change detection tasks. The results from the experiments revealed that, when depth is used as a visual cue, the depth of the MLD has a different effect on the detection of expected changes and unexpected events. When the depth of the MLD is used as a comparison tool, the detection of differences is limited to translation differences in simple stimuli with a white background. These results call into question previous claims made for the MLD regarding operational change detection. In addition, observations and interviews were used to explore whether change blindness occurred in an operational command room. The results suggested that operators develop strategies to recover from interruptions and multitasking. These results call into doubt the wisdom of applying change detection theories to real world operational settings. More importantly, the research serves as a reminder that cognitive limitations found in the laboratory are not always found in real world environments.

This doctoral thesis presents new techniques for improving the structural quality of automatically-acquired architectural 3D models. Common architectural properties such as parallelism and orthogonality of walls and linear structures are exploited. The locations of features such as planes and 3D lines are extracted from the model by using a probabilistic technique (RANSAC). The relationships between the planes and lines are inferred automatically using a knowledge-based architectural model. A numerical algorithm is then used to optimise the position and orientations of the features taking constraints into account. Small irregularities in the model are removed by projecting the irregularities onto the features. Planes and lines in the resulting model are therefore aligned properly to each other, and so the appearance of the resulting model is improved. Our approach is demonstrated using noisy data from both synthetic and real scenes.

Surface reconstruction is one of the main research areas in computer graphics. The goal is to find the best surface representation of the boundary of a real object. The typical input of a surface reconstruction algorithm is a point cloud, possibly obtained by a laser 3D scanner. The raw data from the scanner is usually noisy and contains outliers. Apart from creating models of high visual quality, assuring that a model is as faithful as possible to the original object is also one of the main aims of surface reconstruction. Most surface reconstruction algorithms proposed in the literature assess the reconstructed models either by visual inspection or, in cases where subjective manual input is not possible, by measuring the training error of the model. However, the training error underestimates systematically the test error and encourages overfitting. In this thesis, we provide a method for quantitative assessment in surface reconstruction. We integrate a model averaging method from statistics called bootstrap and define it into our context. Bootstrapping is a resampling procedure that provides statistical parameter. In surface fitting, we obtained error estimate which detect error caused by noise or bad fitting. We also define bootstrap method in context of normal estimation. We obtain variance and error estimates which we use as a quality measure of normal estimates. As application, we provide smoothing algorithm for point clouds and normal smoothing that can handle feature area. We also developed feature detection algorithm.

This thesis describes methods for modelling and visualising fabrics and garments on human body shapes by means of computer systems. The focus is on automatic real-time simulation but, at the same time, realistic appearance of garments is important. Very high physical accuracy in the simulation of mechanical properties of cloth is relaxed, however. We first introduce an image-based collision detection (IBCD) mechanism which harnesses the rasterisation, depth buffer and interpolation units of existing graphics hardware for robust and efficient collision detection and response between body-scan and garment surfaces. We introduce directional velocity modification (DVM), a numerical method to overcome a phenomenon called super-elasticity of conventional mass spring particle systems (MSPS). A reverse engineering technique is presented that enables us to extract assembly information and data for realistic visualisation from photographs of real garments. The images used in this technique are acquired in a set-up that includes a high resolution digital imaging device. Body landmark data is used automatically to pre-position garment panels around a body-scan before virtual sewing. We show that DVM generates visually pleasing garments on static and animated body-scans. The efficiency of the IBCD is demonstrated by a comparison with a traditional geometry based method. A system that exploits the developed techniques was created for Bodymetrics Ltd., at their request. This system is integrated with a 3D whole body scanner for fully automatic virtual try-on of clothes in a department store. The system presents a world first installation and was reported in several newspapers and fashion magazines. While it demonstrates the efficiency and robustness of the developed methods, clothes shoppers can benefit in that the system gives quicker fit-feedback than a traditional mirror in a changing room and can display their dressed body from any angle and distance. In collaboration with a garment designer we also tested the system in a design scenario. In an evaluation of the commercial potential of the developed methods the major players in markets closely related to virtual try-on technology are identified and market entry strategies are discussed.

Computing discrete geodesic distance over triangle meshes is one of the fundamental problems in computational geometry and computer graphics. As the “Big Data Era” arrives, a fast and accurate solution to the geodesic computation problem on large scale models with constantly increasing resolutions is desired. However, it is still challenging to deal with the speed, memory cost and accuracy of the geodesic computation at the same time. This thesis addresses the aforementioned challenge by proposing the Edge- based Windows Grouping (EWG) technique. With the local geodesic information encoded in a “window”, EWG groups the windows based on the mesh edges and processes them together. Thus, the interrelationships among the grouped windows can be utilized to improve the performance of geodesic computation on triangle meshes. Based on EWG, a novel exact geodesic algorithm is proposed in this thesis, which is fast, accurate and memory-efficient. This algorithm computes the geodesic distances at mesh vertices by propagating the geodesic information from the source over the entire mesh. Its high performance comes from its low computational redundancy and management overhead, which are both introduced by EWG. First, the redundant windows on an edge can be removed by comparing its distance with those of the other windows on the same edge. Second, the windows grouped on an edge usually have similar geodesic distances and can be propagated in batches efficiently. To the best of my knowledge, the proposed exact geodesic algorithm is the fastest and most memory-efficient one among all existing methods. In addition, the proposed exact geodesic algorithm is revised and employed to construct the geodesic-metric-based Voronoi diagram on triangle meshes. In this application, the geodesic computation is the bottleneck in both the time and memory costs. The proposed method achieves low memory cost from the key observation that the Voronoi diagram boundaries usually only cross a minority of the meshes’ triangles and most of the windows stored on edges are redundant. As a result, the proposed method resolves the memory bottleneck of the Voronoi diagram construction without sacrificing its speed.

--Context-- This project looked at the development of a stereoscopic 3D environment in which a user is able to draw freely in all three dimensions. The main focus was on the storage and manipulation of the ‘digital ink’ with which the user draws. For a drawing and sketching package to be effective it must not only have an easy to use user interface, it must be able to handle all input data quickly and efficiently so that the user is able to focus fully on their drawing. --Background-- When it comes to sketching in three dimensions the majority of applications currently available rely on vector based drawing methods. This is primarily because the applications are designed to take a users two dimensional input and transform this into a three dimensional model. Having the sketch represented as vectors makes it simpler for the program to act upon its geometry and thus convert it to a model. There are a number of methods to achieve this aim including Gesture Based Modelling, Reconstruction and Blobby Inflation. Other vector based applications focus on the creation of curves allowing the user to draw within or on existing 3D models. They also allow the user to create wire frame type models. These stroke based applications bring the user closer to traditional sketching rather than the more structured modelling methods detailed. While at present the field is inundated with vector based applications mainly focused upon sketch-based modelling there are significantly less voxel based applications. The majority of these applications focus on the deformation and sculpting of voxmaps, almost the opposite of drawing and sketching, and the creation of three dimensional voxmaps from standard two dimensional pixmaps. How to actually sketch freely within a scene represented by a voxmap has rarely been explored. This comes as a surprise when so many of the standard 2D drawing programs in use today are pixel based. --Method-- As part of this project a simple three dimensional drawing program was designed and implemented using C and C++. This tool is known as Sketch3D and was created using a Model View Controller (MVC) architecture. Due to the modular nature of Sketch3Ds system architecture it is possible to plug a range of different data structures into the program to represent the ink in a variety of ways. A series of data structures have been implemented and were tested for efficiency. These structures were a simple list, a 3D array, and an octree. They have been tested for: the time it takes to insert or remove points from the structure; how easy it is to manipulate points once they are stored; and also how the number of points stored effects the draw and rendering times. One of the key issues brought up by this project was devising a means by which a user is able to draw in three dimensions while using only two dimensional input devices. The method settled upon and implemented involves using the mouse or a digital pen to sketch as one would in a standard 2D drawing package but also linking the up and down keyboard keys to the current depth. This allows the user to move in and out of the scene as they draw. A couple of user interface tools were also developed to assist the user. A 3D cursor was implemented and also a toggle, which when on, highlights all of the points intersecting the depth plane on which the cursor currently resides. These tools allow the user to see exactly where they are drawing in relation to previously drawn lines. --Results-- The tests conducted on the data structures clearly revealed that the octree was the most effective data structure. While not the most efficient in every area, it manages to avoid the major pitfalls of the other structures. The list was extremely quick to render and draw to the screen but suffered severely when it comes to finding and manipulating points already stored. In contrast the three dimensional array was able to erase or manipulate points effectively while the draw time rendered the structure effectively useless, taking huge amounts of time to draw each frame. The focus of this research was on how a 3D sketching package would go about storing and accessing the digital ink. This is just a basis for further research in this area and many issues touched upon in this paper will require a more in depth analysis. The primary area of this future research would be the creation of an effective user interface and the introduction of regular sketching package features such as the saving and loading of images.