Virtual laboratories can offer increased availability and flexibility for students along with alleviating scaling issues within educational institutions. Virtual Reality (VR) depicts an interesting option because it can place users into computergenerated environments and allows interactive experiences with increased immersion and presence. Although hardware devices for VR are available off-the-shelf and possess a variety of functionality, the actual realization and integration into an existing course remain challenging. In particular, students should not only be able to gain knowledge and skills in the created virtual environments, but they should be able to transfer these to real-world scenarios. We aim to virtualize a specific physical laboratory for civil engineering (CE) using VR and concurrently demonstrate the entire workflow from the didactic concept, prototype design and implementation up to the evaluation of the lab by CE students. The virtual laboratory (DigiLabVR) is centered on the construction of reinforced concrete beams, requiring custom interaction along a series of different stations. Developing relevant VR content tailored to engineering education is usually complex and resource-intensive. To address this challenge within a small team, DigiLabVR was developed in two stages using a commercial game engine and piloted in two different scenarios. The first pilot was conducted with students from other disciplines and served mainly to obtain general feedback and to drive the development process. The second one was conducted within a regular CE class using an updated and extended prototype. While the first pilot demonstrated increased student motivation, the second one showed reduced temporal effort in comparison with the baseline approach. The feasibility of employing a VR laboratory for this specific course could be confirmed, and VR in such a context was well received by the students. As this first in-class pilot represented content-wise a rather introductory level, notable knowledge gains could not be observed and student feedback indicated a need for instructions at a more advanced level.

Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, optically variable devices such as holograms are important, but difficult to inspect. Augmented Reality can provide all relevant information on standard mobile devices. However, hologram verification on mobiles still takes long and provides lower accuracy than inspection by human individuals using appropriate reference information. We aim to address these drawbacks by automatic matching combined with a special parametrization of an efficient goal-oriented user interface which supports constrained navigation. We first evaluate a series of similarity measures for matching hologram patches to provide a sound basis for automatic decisions. Then a re-parametrized user interface is proposed based on observations of typical user behavior during document capture. These measures help to reduce capture time to approximately 15 s with better decisions regarding the evaluated samples than what can be achieved by untrained users.

Paper documents such as passports, visas and banknotes are frequently checked by inspection of security elements. In particular, view-dependent elements such as holograms are interesting, but the expertise of individuals performing the task varies greatly. Augmented Reality systems can provide all relevant information on standard mobile devices. Hologram verification still takes long and causes considerable load for the user. We aim to address this drawback by first presenting a work flow for recording and automatic matching of hologram patches. Several user interfaces for hologram verification are presented, aiming to noticeably reduce verification time. We evaluate the most promising interfaces in a user study with prototype applications running on off-the-shelf hardware. Our results indicate that there is a significant difference in capture time between interfaces but that users do not prefer the fastest interface.

Verification of paper documents is an important part of checking a person's identity, authorization for access or simply establishing a trusted currency. Many documents such as passports or paper bills include holograms or other view-dependent elements that are difficult to forge and therefore are used to verify the genuineness of that document. View-dependent elements change their appearance based both on viewing direction and dominant light sources, thus it requires special knowledge and training to accurately distinguish original elements from forgeries. We present an interactive application for mobile devices that integrates the recognition of the documents with the interactive verification of view-dependent elements. The system recognizes and tracks the paper document, provides user guidance for view alignment and presents a stored image of the element's appearance depending on the current view of the document also recording user decisions. We describe how to model and capture the underlying spatially varying BRDF representation of view-dependent elements. Furthermore, we evaluate this approach within a user study and demonstrate that such a setup captures images that are recognizable and that can be correctly verified.

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