Detection of Non-Stationary Photometric Perturbations on Projection Screens

Interfaces based on projection screens have become increasingly more popular in recent years, mainly due to the large screen size and resolution that they provide, as well as their stereo-vision capabilities. This work shows a local method for real-time detection of non-stationary photometric perturbations in projected images by means of computer vision techniques. The method is based on the computation of differences between the images in the projector’s frame buffer and the corresponding images on the projection screen observed by the camera. It is robust under spatial variations in the intensity of light emitted by the projector on the projection surface and also robust under stationary photometric perturbations caused by external factors. Moreover, we describe the experiments carried out to show the reliability of the method

Evaluating human-centered approaches for geovisualization

Working with two small group of domain experts I evaluate human-centered approaches to application development which are applicable to geovisualization, following an ISO13407 taxonomy that covers context of use, eliciting requirements, and design. These approaches include field studies and contextual analysis of subjects' context; establishing requirements using a template, via a lecture to communicate geovisualization to subjects and by communicating subjects' context to geovisualization experts with a scenario; autoethnography to understand the geovisualization design process; wireframe, paper and digital interactive prototyping with alternative protocols; and a decision making process for prioritising application improvement. I find that the acquisition and use of real user data is key; that a template approach and teaching subjects about visualization tools and interactions both fail to elicit useful requirements for a visualization application. Consulting geovisualization experts with a scenario of user context and samples of user data does yield suggestions for tools and interactions of use to a visualization designer. The complex and composite natures of both visualization and human-centered domains, incorporating learning from both domains, with user context, makes design challenging. Wireframe, paper and digital interactive prototypes mediate between the user and visualization domains successfully, eliciting exploratory behaviour and suggestions to improve prototypes. Paper prototypes are particularly successful at eliciting suggestions and especially novel visualization improvements. Decision-making techniques prove useful for prioritising different possible improvements, although domain subjects select data-related features over more novel alternative and rank these more inconsistently. The research concludes that understanding subject context of use and data is important and occurs throughout the process of engagement with domain experts, and that standard requirements elicitation techniques are unsuccessful for geovisualization. Engagement with subjects at an early stage with simple prototypes incorporating real subject data and moving to successively more complex prototypes holds the best promise for creating successful geovisualization applications

Enhanced visualisation techniques to support access to personal information across multiple devices

The increasing number of devices owned by a single user makes it increasingly difficult to access, organise and visualise personal information (PI), i.e. documents and media, across these devices. The primary method that is currently used to organise and visualise PI is the hierarchical folder structure, which is a familiar and widely used means to manage PI. However, this hierarchy does not effectively support personal information management (PIM) across multiple devices. Current solutions, such as the Personal Information Dashboard and Stuff I’ve Seen, do not support PIM across multiple devices. Alternative PIM tools, such as Dropbox and TeamViewer, attempt to provide a means of accessing PI across multiple devices, but these solutions also suffer from several limitations. The aim of this research was to investigate to what extent enhanced information visualisation (IV) techniques could be used to support accessing PI across multiple devices. An interview study was conducted to identify how PI is currently managed across multiple devices. This interview study further motivated the need for a tool to support visualising PI across multiple devices and identified requirements for such an IV tool. Several suitable IV techniques were selected and enhanced to support PIM across multiple devices. These techniques comprised an Overview using a nested circles layout, a Tag Cloud and a Partition Layout, which used a novel set-based technique. A prototype, called MyPSI, was designed and implemented incorporating these enhanced IV techniques. The requirements and design of the MyPSI prototype were validated using a conceptual walkthrough. The design of the MyPSI prototype was initially implemented for a desktop or laptop device with mouse-based interaction. A sample personal space of information (PSI) was used to evaluate the prototype in a controlled user study. The user study was used to identify any usability problems with the MyPSI prototype. The results were highly positive and the participants agreed that such a tool could be useful in future. No major problems were identified with the prototype. The MyPSI prototype was then implemented on a mobile device, specifically an Android tablet device, using a similar design, but supporting touch-based interaction. Users were allowed to upload their own PSI using Dropbox, which was visualised by the MyPSI prototype. A field study was conducted following the Multi-dimensional In-depth Long-term Case Studies approach specifically designed for IV evaluation. The field study was conducted over a two-week period, evaluating both the desktop and mobile versions of the MyPSI prototype. Both versions received positive results, but the desktop version was slightly preferred over the mobile version, mainly due to familiarity and problems experienced with the mobile implementation. Design recommendations were derived to inform future designs of IV tools to support accessing PI across multiple devices. This research has shown that IV techniques can be enhanced to effectively support accessing PI across multiple devices. Future work will involve customising the MyPSI prototype for mobile phones and supporting additional platforms

Automatic Lecture Recording

Lecture recording has become a very common tool to provide students with additional media for their examination preparations. While its effort has to stay reasonable, only a very basic way of recording is done in many cases. Therefore, watching the resulting videos can get very boring completely independent of how interesting the original topic or session was. This thesis proposes a new approach to lecture recordings by letting distributed computers emulate the work of a human camera team, which is the natural way of creating attractive recordings. This thesis is structured in six chapters, starting with the examination of the current situation, and taking its constraints into account. The first chapter concludes with a reflection on related work. Chapter two is about the design of our prototype system. It is deduced from a human camera team in the real world which gets transferred into the virtual world. Finally, a detailed overview about all parts necessary for our prototype and their planned functionality is given. In chapter three, the implementation of all parts and tasks and the incidents occurring during implementation are described in detail. Chapter four describes the technical experiences made with the different parts during development, testing and evaluation with a view to functionality, performance, and an proposal towards future work. The evaluation of the whole system with students is presented and discussed in the fifth chapter. Chapter six concludes this thesis by summing up the facts and gives an outlook on future work

Enhanced visualisation techniques to support access to personal information across multiple devices

The increasing number of devices owned by a single user makes it increasingly difficult to access, organise and visualise personal information (PI), i.e. documents and media, across these devices. The primary method that is currently used to organise and visualise PI is the hierarchical folder structure, which is a familiar and widely used means to manage PI. However, this hierarchy does not effectively support personal information management (PIM) across multiple devices. Current solutions, such as the Personal Information Dashboard and Stuff I’ve Seen, do not support PIM across multiple devices. Alternative PIM tools, such as Dropbox and TeamViewer, attempt to provide a means of accessing PI across multiple devices, but these solutions also suffer from several limitations. The aim of this research was to investigate to what extent enhanced information visualisation (IV) techniques could be used to support accessing PI across multiple devices. An interview study was conducted to identify how PI is currently managed across multiple devices. This interview study further motivated the need for a tool to support visualising PI across multiple devices and identified requirements for such an IV tool. Several suitable IV techniques were selected and enhanced to support PIM across multiple devices. These techniques comprised an Overview using a nested circles layout, a Tag Cloud and a Partition Layout, which used a novel set-based technique. A prototype, called MyPSI, was designed and implemented incorporating these enhanced IV techniques. The requirements and design of the MyPSI prototype were validated using a conceptual walkthrough. The design of the MyPSI prototype was initially implemented for a desktop or laptop device with mouse-based interaction. A sample personal space of information (PSI) was used to evaluate the prototype in a controlled user study. The user study was used to identify any usability problems with the MyPSI prototype. The results were highly positive and the participants agreed that such a tool could be useful in future. No major problems were identified with the prototype. The MyPSI prototype was then implemented on a mobile device, specifically an Android tablet device, using a similar design, but supporting touch-based interaction. Users were allowed to upload their own PSI using Dropbox, which was visualised by the MyPSI prototype. A field study was conducted following the Multi-dimensional In-depth Long-term Case Studies approach specifically designed for IV evaluation. The field study was conducted over a two-week period, evaluating both the desktop and mobile versions of the MyPSI prototype. Both versions received positive results, but the desktop version was slightly preferred over the mobile version, mainly due to familiarity and problems experienced with the mobile implementation. Design recommendations were derived to inform future designs of IV tools to support accessing PI across multiple devices. This research has shown that IV techniques can be enhanced to effectively support accessing PI across multiple devices. Future work will involve customising the MyPSI prototype for mobile phones and supporting additional platforms

Designing technology for young children: guidelines grounded in a literature investigation on child development and children's technology

This thesis is about the design of technology for children from five to eight years of age. The majority of available guidelines and principles for design or evaluation of technology support the design of products aimed at adults. The limited guidelines available for design of young children's technology do not focus sufficiently on age-related requirements or they offer high-level advice that is only useful in the planning stages of design. Working from the assumption that knowledge available in the literature provides sufficient information to support this process, my aim with this study was to demonstrate how a dependable and useful set of guidelines for the design of technology for children aged five to eight years could be derived from an existing body of knowledge. Development of the guidelines firstly involved research into the psychological theories of children's development to identify those elements of development and the characteristics of children that may have bearing on children's use of technology. Secondly, the literature on children's development of specific skills such as literacy and mathematics was investigated. The available literature on young children's use of technology was studied next and, finally, the applicability of existing design guidelines and principles for children's products evaluated. Throughout this literature investigation the researcher gathered design-relevant factors that could potentially become design guidelines. Using qualitative data analysis techniques, more than five hundred such data elements were systematically coded, processed, analysed and categorised. The result is three hundred and fifty guidelines organised into a framework of six categories and twenty-six subcategories that integrates the relevant theoretical fields and provides practical support for designers. To demonstrate the credibility and usefulness of the emerging guidelines they were used to do an evaluation and re-design of an existing product aimed at the target group. The thesis reports in detail on the different stages of the research, and systematically takes the reader through the process of deriving guidelines from existing theory and research findings, and integrating them into a useful framework.School of ComputingPhD. (Computer Science