Publikationen

Fragestellung Am Beispiel der Urosonographie wurde die Nützlichkeit eines simulationsbasierten Lernspiels für die Ultraschallausbildung untersucht. Material und Methodik Das im Rahmen eines Hochschulprojekts entwickelte Ultraschall-Lernspiel SonoGame wurde in einem Urosonographie-Grundkurs eingesetzt und evaluiert. Insgesamt 32 Teilnehmer in sechs Gruppen nutzten das Lernspiel für jeweils 30 Minuten pro Gruppe. Mit simulierten Ultraschallsonden wurden virtuelle 3D-Volumen mittels 2D-Schnittbildern untersucht. Folgende Aufgaben wurden dabei gestellt: 1. Mit simulierter Konvex-Sonde: Untersuchung eines unbekannten Volumens, das aus verschiedenen geometrischen Körpern zusammengesetzt wurde, und a) Identifizierung des Volumens mit Hilfe einer Auswahl von vier in 3D-Darstellung präsentierten möglichen Lösungen sowie b) Erzeugen eines vorgegebenen Schnittbilds 2. Mit simulierter transrektaler Sonde: Training einer Prostatabiopsie mit Nadelführungshilfe, wobei in einem vereinfachten virtuellen Anatomiemodell vorgegebene Zielstrukturen mittels eines im Ultraschallbild visualisierten Nadelpfades erreicht werden mussten Die 2D-Schnittbilder wurden dabei je nach Schwierigkeitsstufe farbig oder ultraschallartig dargestellt. Die Teilnehmer wurden gebeten, die Nützlichkeit des Lernspiels bezüglich verschiedener Aspekte mit den Antwortmöglichkeiten 1 (keine Zustimmung) bis 5 (volle Zustimmung) zu bewerten. Ergebnisse 29 Teilnehmer gaben eine Bewertung ab. Die allgemeine Nützlichkeit für die Ultraschallausbildung wurde mit 4,3 (±0,9) bewertet, die Steigerung des Raumvorstellungsvermögens mit 4,6 (±0,7), die Steigerung des Verständnisses für die Handhabung des Schallkopfes mit 4,4 (±0,7) und die Steigerung der Lernmotivation für Ultraschall-Themen mit 4,4 (±0,9). Schlussfolgeurng Ein simulationsbasiertes Lernspiel kann eine nützliche Ergänzung in der Ultraschallausbildung darstellen, insbesondere zur Steigerung der visuell-räumlichen und visuell-motorischen Fähigkeiten.

Common approaches for gamepad-based navigation in desktop 3D games are often not suited for inexperienced players. In particular, novices have difficulties in simultaneously controlling movement and viewing direction in a virtual 3D scene. Here, we compare the currently predominant 3D navigation approach with an alternative approach that is inspired by early 3D games. 20 test users with little or no 3D gaming experience used both approaches to walk along a test course in a virtual 3D scene containing different obstacles. Using the alternative navigation approach, the users finished the course faster and with fewer errors than with the predominant navigation approach. In addition, the pragmatic and the hedonic quality of the alternative approach were rated higher. As a conclusion, the presented alternative approach should be given consideration when designing 3D (serious) games or similar applications for inexperienced players, not only for gamepad-based navigation, but also for comparable interfaces like the typical combination of keyboard and mouse control.

Sensory perception is an important part of reading. Physical books are experiencedhaptically, for instance when turning pages using one s fingers. When browsing e-bookson current reader devices, this tangibility is missing. Our research investigates if the userexperience of e-book readers can be improved by adding haptic feedback to the act of browsing. For this purpose an e-book reader with applied nylon wires has beendeveloped, with which browsing becomes tangible. The prototype has been tested withusers and compared to an e-book reader with a common touch-controlled scrollbar usingquantitative and qualitative methods. The results show that the scrollbar version enabledparticipants to navigate faster. However, the prototype with haptic feedback receivedbetter ratings in terms of pragmatic and hedonic quality as well as attractiveness.Additionally, tangible browsing enabled users to navigate more precisely. This wouldexplain, why participants appreciated the pragmatic qualities, even though the act of browsing was slower. Therefore haptic feedback can improve the acceptance of e-books.

The resolution of current head-mounted displays leads to poor readability of text inrealistic virtual reality (VR) simulations. This results in unnatural user behavior. Here, three approaches for improving the readability of text in VR have been investigated:1) constantly magnifying a part of the screen (version "lens"), 2) magnifying sceneelements such as signs depending on the gaze direction (version "magnify") and3) augmenting the scene by adding floating texts (version "AR"). These approaches havebeen implemented as prototypes and tested by twelve users, using a virtual supermarketas an exemplary VR scene. The participants filled out a questionnaire, rating theirexperience with the different approaches. Additionally, the time required for readinggiven texts (price tags) has been measured and compared for each approach. With theAR version, the reading time was significantly shorter than the reading time without anyaids. The other versions offered no advantages. The AR version was also rated best in thequalitative evaluation. However, the other versions offer potential for improvement, which can be addressed in future research.

Six Degrees of Freedom (6DoF) controllers are usually expensive and/or complex to set up. A smartphone as 6DoF controller could be a cost-effective and simple alternative. Within the scope of this research, the application context of medical ultrasound training is addressed, in which the smartphone could be used to control a virtual probe. For this purpose, the difference in rotation and position tracking has been examined between an HTC Vive Tracker as an established reference system and a smartphone using ARCore. Additionally, the usability of the smartphone for controlling a virtual ultrasound probe has been qualitatively evaluated by nine subjects using a simplified test system. ARCore s 6DoF tracking is generally less reliable and accurate than the HTC Vive tracker. However, both the characteristics of the measured tracking errors and the qualitative evaluation show that an ARCore-based 6DoF tracking can be used as a simple and acceptable solution for controlling a virtual ultrasound probe.