Open Access

Computer graphics research strives to synthesize images of a high visual realism that are indistinguishable from real visual experiences. While modern image synthesis approaches enable to create digital images of astonishing complexity and beauty, processing resources remain a limiting factor. Here, rendering efficiency is a central challenge involving a trade-off between visual fidelity and interactivity. For that reason, there is still a fundamental difference between the perception of the physical world and computer-generated imagery. At the same time, advances in display technologies drive the development of novel display devices. The dynamic range, the pixel densities, and refresh rates are constantly increasing. Display systems enable a larger visual field to be addressed by covering a wider field-of-view, due to either their size or in the form of head-mounted devices. Currently, research prototypes are ranging from stereo and multi-view systems, head-mounted devices with adaptable lenses, up to retinal projection, and lightfield/holographic displays. Computer graphics has to keep step with, as driving these devices presents us with immense challenges, most of which are currently unsolved. Fortunately, the human visual system has certain limitations, which means that providing the highest possible visual quality is not always necessary. Visual input passes through the eye’s optics, is filtered, and is processed at higher level structures in the brain. Knowledge of these processes helps to design novel rendering approaches that allow the creation of images at a higher quality and within a reduced time-frame. This thesis presents the state-of-the-art research and models that exploit the limitations of perception in order to increase visual quality but also to reduce workload alike - a concept we call perception-driven rendering. This research results in several practical rendering approaches that allow some of the fundamental challenges of computer graphics to be tackled. By using different tracking hardware, display systems, and head-mounted devices, we show the potential of each of the presented systems. The capturing of specific processes of the human visual system can be improved by combining multiple measurements using machine learning techniques. Different sampling, filtering, and reconstruction techniques aid the visual quality of the synthesized images. An in-depth evaluation of the presented systems including benchmarks, comparative examination with image metrics as well as user studies and experiments demonstrated that the methods introduced are visually superior or on the same qualitative level as ground truth, whilst having a significantly reduced computational complexity.

In mathematical modeling by means of performance models, the Fitness-Fatigue Model (FF-Model) is a common approach in sport and exercise science to study the training performance relationship. The FF-Model uses an initial basic level of performance and two antagonistic terms (for fitness and fatigue). By model calibration, parameters are adapted to the subject’s individual physical response to training load. Although the simulation of the recorded training data in most cases shows useful results when the model is calibrated and all parameters are adjusted, this method has two major difficulties. First, a fitted value as basic performance will usually be too high. Second, without modification, the model cannot be simply used for prediction. By rewriting the FF-Model such that effects of former training history can be analyzed separately – we call those terms preload – it is possible to close the gap between a more realistic initial performance level and an athlete's actual performance level without distorting other model parameters and increase model accuracy substantially. Fitting error of the preload-extended FF-Model is less than 32% compared to the error of the FF-Model without preloads. Prediction error of the preload-extended FF-Model is around 54% of the error of the FF-Model without preloads.

This work addresses the issue of finding an optimal flight zone for a side-by-side tracking and following Unmanned Aerial Vehicle(UAV) adhering to space-restricting factors brought upon by a dynamic Vector Field Extraction (VFE) algorithm. The VFE algorithm demands a relatively perpendicular field of view of the UAV to the tracked vehicle, thereby enforcing the space-restricting factors which are distance, angle and altitude. The objective of the UAV is to perform side-by-side tracking and following of a lightweight ground vehicle while acquiring high quality video of tufts attached to the side of the tracked vehicle. The recorded video is supplied to the VFE algorithm that produces the positions and deformations of the tufts over time as they interact with the surrounding air, resulting in an airflow model of the tracked vehicle. The present limitations of wind tunnel tests and computational fluid dynamics simulation suggest the use of a UAV for real world evaluation of the aerodynamic properties of the vehicle’s exterior. The novelty of the proposed approach is alluded to defining the specific flight zone restricting factors while adhering to the VFE algorithm, where as a result we were capable of formalizing a locally-static and a globally-dynamic geofence attached to the tracked vehicle and enclosing the UAV.

Background: Virtual reality combined with spherical treadmills is used across species for studying neural circuits underlying navigation. New Method: We developed an optical flow-based method for tracking treadmil ball motion in real-time using a single high-resolution camera. Results: Tracking accuracy and timing were determined using calibration data. Ball tracking was performed at 500 Hz and integrated with an open source game engine for virtual reality projection. The projection was updated at 120 Hz with a latency with respect to ball motion of 30 ± 8 ms. Comparison: with Existing Method(s) Optical flow based tracking of treadmill motion is typically achieved using optical mice. The camera-based optical flow tracking system developed here is based on off-the-shelf components and offers control over the image acquisition and processing parameters. This results in flexibility with respect to tracking conditions – such as ball surface texture, lighting conditions, or ball size – as well as camera alignment and calibration. Conclusions: A fast system for rotational ball motion tracking suitable for virtual reality animal behavior across different scales was developed and characterized.

Anne Dreller shows that data sharing offers great opportunities and huge value creation potential for the business world. Despite many opportunities that data sharing promises, the business world has not fully operationalized this fact yet, due to various existing challenges. Thus, an exemplary, future-oriented, and platform-based data sharing business model is developed for the startup Quemey. This business model is also equipped with prioritized implementation advice, including measures like focusing on strong values for all platform participants, growing their business into a powerful monopolist position, and eliminating barriers of technological, contractual and legal or data privacy uncertainties.

Advances in computer graphics enable us to create digital images of astonishing complexity and realism. However, processing resources are still a limiting factor. Hence, many costly but desirable aspects of realism are often not accounted for, including global illumination, accurate depth of field and motion blur, spectral effects, etc. especially in real‐time rendering. At the same time, there is a strong trend towards more pixels per display due to larger displays, higher pixel densities or larger fields of view. Further observable trends in current display technology include more bits per pixel (high dynamic range, wider color gamut/fidelity), increasing refresh rates (better motion depiction), and an increasing number of displayed views per pixel (stereo, multi‐view, all the way to holographic or lightfield displays). These developments cause significant unsolved technical challenges due to aspects such as limited compute power and bandwidth. Fortunately, the human visual system has certain limitations, which mean that providing the highest possible visual quality is not always necessary. In this report, we present the key research and models that exploit the limitations of perception to tackle visual quality and workload alike. Moreover, we present the open problems and promising future research targeting the question of how we can minimize the effort to compute and display only the necessary pixels while still offering a user full visual experience.

In this course, we will take a detailed look at various breeds of spatial navigation interfaces that allow for locomotion in digital 3D environments such as games, virtual environments or even the exploration of abstract data sets. We will closely look into the basics of navigation, unraveling the psychophysics (including wayfinding) and actual navigation (travel) aspects. The theoretical foundations form the basis for the practical skillset we will develop, by providing an in-depth discussion of navigation devices and techniques, and a step-by-step discussion of multiple real-world case studies. Doing so, we will cover the full range of navigation techniques from handheld to full-body, highly engaging and partly unconventional methods and tackle spatial navigation with hands-on-experience and tips for design and validation of novel interfaces. In particular, we will be looking at affordable setups and ways to “trick” out users to enable a realistic feeling of self-motion in the explored environments. As such, the course unites the theory and practice of spatial navigation, serving as entry point to understand and improve upon currently existing methods for the application domain at hand.

HCI and CSCW research as well as practice has strongly indicated the value of integrating (end) users in software development processes. Such integration can help address actual needs and wants, to avoid undesirable developments and to strengthen the User Experience of a product. A user-focused approach to software development has some conceptual overlap with agile software development practices, such as quick and iterative (user) testing. However, out in the wild, organisations seem to have difficulties actually mapping user-centered development with agile processes for a variety of reasons ranging from organisational or hierarchical aspects up to financial issues. This problem seems specially prevalent in Small and Medium sized Enterprises (SMEs) where such constraints can be even tighter than in larger organisations. To help understand those problems and to identify possible solutions, we turned to three quite different German software SMEs, varying in size, market focus and organisational structure. By way of qualitative field studies, we were able to identify key roles and tools as well as methodological, organisational and analytical practices and challenges in integrating (end) users into agile software development.

UX-Professionals stehen vor der Aufgabe ihre Fertigkeiten und Kenntnisse kontinuierlich auszubauen. Eine Möglichkeit dies zu tun sind Communities of Practice, also Gemeinschaften von Personen mit ähnlichen Aufgaben und Schwerpunkten sowie einem gemeinsamen Interesse an Lösungen. Sie agieren weitgehend selbstorganisiert und dienen dem Austausch und der gegenseitigen Unterstützung. So entstehen ein gemeinsamer Wissensschatz sowie ein Netzwerk zwischen allen UX-Interessierten. Der Aufbau einer Community of Practice für UX-Professionals wurde in einem mittelständigen Unternehmen über 18 Monate begleitet und ausgewertet. Die Ergebnisse führten zu Handlungsempfehlungen, um Hindernisse beim Aufbau zu reduzieren und einen Mehrwert für alle Beteiligten herbeizuführen.

Informations- und Kommunikationstechnologie (IKT) in den Bereichen Smart Home und Smart Living ist durch die zunehmende Vernetzung des häuslichen Anwendungsfelds mit der Digitalisierung des Stromnetzes, alternativen Möglichkeiten der Energiegewinnung und -speicherung und neuer Mobilitätskonzepte geprägt und zu einem unverzichtbaren Bestandteil privaten wie unternehmerischen Handelns geworden.

Die Entwicklung intelligenter Technologien zur Unterstützung im Alltag und in den eigenen vier Wänden begleitet unsere Gesellschaft schon seit dem Zeitalter des Personal Computers. Mit dem Aufkommen des Internet der Dinge und begünstigt durch immer kleiner und günstiger werdende Hardware ergeben sich neue Potenziale, die das Thema Smart Home attraktiver als je zuvor werden lassen. Eine Vielzahl der aktuell im Markt verfügbaren Lösungen adressiert die Bedürfnisse Komfort, Sicherheit und effiziente Energienutzung. Die versprochene Intelligenz – smartness, wie sie der Begriff selbst suggeriert – wird vor allem bei Lösungen im privaten Nachrüstbereich überwiegend durch die Interaktion der Nutzer selbst und entsprechende regelbasierte Konfigurationen erzeugt. Diese notwendige Art der Interaktion und die damit verbundenen Aufwände sind jedoch von starker Bedeutung für das gesamte Nutzungserlebnis Smart Home und führen nicht selten zu Frustration oder gar Resignation in der Nutzung.