Image grid display: A study on automatic scrolling presentation

In this paper we describe a study on image grid display with automatic vertical scrolling. While scroll operations are normally carried out manually by the user, in the context of RSVP (Rapid Serial Visual Presentation) techniques this work considers a presentation mode in which the image grid is automatically scrolled. Through experiments carried out with 50 testers, we have investigated user performance while looking for specific target subjects within large collections of images. Different numbers of columns and scrolling speeds have been considered. The search task implied both clicking on the identified target pictures and simply vocally stating their visual recognition. To this purpose, and to identify possible specific gaze behaviours, eye tracking technology has been exploited. The obtained results show that number of columns and scroll speed do affect search performance. Moreover, the userâs gaze tends to focus on different screen areas depending on the values of these two parameters. Although it is not possible to definitely find an optimal columnsâspeed combination that is valid in all cases, the particular context of use can suggest feasible solutions according to oneâs needs. To the best of our knowledge, image grid display with automatic scrolling has never been studied to date. Keywords: Image grid display, Automatic scrolling, Image presentation modes, Image collections, Rapid serial visual presentatio

Realistic electronic books

People like books. They are convenient and can be accessed easily and enjoyably. In contrast, many view the experience of accessing and exploring electronic documents as dull, cumbersome and disorientating. This thesis claims that modelling digital documents as physical books can significantly improve reading performance. To investigate this claim, a realistic electronic book model was developed and evaluated. In this model, a range of properties associated with physical books---analogue page turning, bookmarks and annotations---are emulated. Advantage is also taken of the digital environment by supporting hyperlinks, multimedia, full-text search over terms and synonyms, automatically cross referencing documents with an online encyclopaedia, and producing a back-of-the-book index. The main technical challenge of simulating physical books is finding a suitable technique for page turning that is sufficiently realistic, yet lightweight, responsive, scalable and accessible. Several techniques were surveyed, implemented and evaluated. The chosen technique allows realistic books to be presented in the Adobe Flash Player, the most widely used browser plug-in on the Web. A series of usability studies were conducted to compare reading performance while performing various tasks with HTML, PDF, physical books, and simulated books. They revealed that participants not only preferred the new interface, but completed the tasks more efficiently, without any loss in accuracy

Uncertainty-aware video visual analytics of tracked moving objects

Vast amounts of video data render manual video analysis useless while recent automatic video analytics techniques suffer from insufficient performance. To alleviate these issues we present a scalable and reliable approach exploiting the visual analytics methodology. This involves the user in the iterative process of exploration hypotheses generation and their verification. Scalability is achieved by interactive filter definitions on trajectory features extracted by the automatic computer vision stage. We establish the interface between user and machine adopting the VideoPerpetuoGram (VPG) for visualization and enable users to provide filter-based relevance feedback. Additionally users are supported in deriving hypotheses by context-sensitive statistical graphics. To allow for reliable decision making we gather uncertainties introduced by the computer vision step communicate these information to users through uncertainty visualization and grant fuzzy hypothesis formulation to interact with the machine. Finally we demonstrate the effectiveness of our approach by the video analysis mini challenge which was part of the IEEE Symposium on Visual Analytics Science and Technology 2009

Survey of image-based representations and compression techniques

In this paper, we survey the techniques for image-based rendering (IBR) and for compressing image-based representations. Unlike traditional three-dimensional (3-D) computer graphics, in which 3-D geometry of the scene is known, IBR techniques render novel views directly from input images. IBR techniques can be classified into three categories according to how much geometric information is used: rendering without geometry, rendering with implicit geometry (i.e., correspondence), and rendering with explicit geometry (either with approximate or accurate geometry). We discuss the characteristics of these categories and their representative techniques. IBR techniques demonstrate a surprising diverse range in their extent of use of images and geometry in representing 3-D scenes. We explore the issues in trading off the use of images and geometry by revisiting plenoptic-sampling analysis and the notions of view dependency and geometric proxies. Finally, we highlight compression techniques specifically designed for image-based representations. Such compression techniques are important in making IBR techniques practical.published_or_final_versio