Andrea Bönsch, M. Sc.|
Phone: +49 241 80 24922
Fax: +49 241 80 6 24922
Office hours: Whenever the door is open from Monday to Thursday.
As member of the Virtual Reality and Immersive Visualization Group, I take up different roles:
I am a doctoral candidate conducting basic research in the area of Virtual Humans. I supervise master and undergraduate students as well as student assistants. Besides, I am the training supervisor for our Mathematical and Technical Software Developer apprentices.
Furthermore, I am the head of our service team. Our responsibilities include operating our VR Lab and supporting institutes of RWTH Aachen as well as external cooperation partners by integrating virtual reality and immersive visualization technologies into their research projects.
My research focuses on investigating the impact of the presence of virtual, human-like representations, so-called virtual humans (VH), in immersive virtual environments. Currently I do basic research on computer-controlled virtual agents. Here, I examine the influence of personal space requirements as well as agents’ behaviors on users in different scenarios.
I am particularly interested in VH-based training simulations and support systems in which the VHs fulfill the role of assistants, teachers or communication partners.
- Reviewer at
- Subreviewer at
- Visiting Scholar at USC Institute for Creative Technologies, Los Angeles,
USA, working with Ari Shapiro (mid-February till mid-April, 2017)
- Seminar Advisor, regularly in the group's seminars and pro-seminars
- Lecturer, Virtual Humans part in "Advanced Topics on Virtual Reality (VR II)", Summer 2017
- Teaching Assistant, exercises for Virtual Reality (VR I), Winter 2011/2012
- Virtuelle Assistenten: Untersuchung zweier Anwesenheitsstrategien
(bachelor thesis by Jan Hoffmann, 2016, ongoing)
- An Intelligent Recommendation System for an Efficient and Effective Control of Virtual Agents in a Wizard-of-Oz Paradigm
(master thesis by Robert Trisnadi, 2016)
- Do Not Invade - A Virtual Reality Framework to Design Personal Space Studies
(bachelor thesis by Jan Schnathmeier, 2016)
- Virtual Sightseeing - A Virtual Reality Framework for Visualizing Cities Based on CityGML
(bachelor thesis by Timothy A.W. Blut, 2016)
- Clippy revisited – Intelligent, Minimal Virtual Agents in Immersive Virtual Environments
(bachelor thesis by David Gilbert, 2016)
- Automated Generation of High-quality Collision-free Paths through Virtual Environments
(bachelor thesis by Jonathan Wendt, 2014, co-supervised)
- Concept and Implementation of Techniques for Interactively Experiencing Virtual Works of Art in Immersive Virtual Environments
(master thesis by Dennis Scully, 2014, co-supervised, publication)
- Integration eines effizienten Verfahrens zur korrekten Darstellung transparenter Objekte in ViSTA
(bachelor thesis by Joachim Herber, 2013, co-supervised)
- Generating and Animating Virtual Humans (Robert Trisnadi, 2016)
- Customization of the Appearance of Virtual Characters (Yannick Donners, 2016)
- Trainer according to the German Trainer Aptitude Ordinance (AEVO), Chamber of Industry and Commerce Aachen, June 2015
- Master of Science, Computer Science, RWTH Aachen University, January 2015
- Mathematical and Technical Software Developer (MaTSE), Chamber of Industry and Commerce Aachen, August 2010
- Bachelor of Science, Scientific Programming, University of Applied Sciences Aachen, July 2010
It is increasingly common to embed embodied, human-like, virtual agents into immersive virtual environments for either of the two use cases: (1) populating architectural scenes as anonymous members of a crowd and (2) meeting or supporting users as individual, intelligent and conversational agents. However, the new trend towards intelligent cyber physical systems inherently combines both use cases. Thus, we argue for the necessity of multiagent systems consisting of anonymous and autonomous agents, who temporarily turn into intelligent individuals. Besides purely enlivening the scene, each agent can thus be engaged into a situation-dependent interaction by the user, e.g., into a conversation or a joint task. To this end, we devise components for an agent’s behavioral design modeling the transition between an anonymous and an individual agent when a user approaches.
Embodied, virtual agents provide users assistance in agent-based support systems. To this end, two closely linked factors have to be considered for the agents’ behavioral design: their presence time (PT), i.e., the time in which the agents are visible, and the approaching time (AT), i.e., the time span between the user’s calling for an agent and the agent’s actual availability.
This work focuses on human-like assistants that are embedded in immersive scenes but that are required only temporarily. To the best of our knowledge, guidelines for a suitable trade-off between PT and AT of these assistants do not yet exist. We address this gap by presenting the results of a controlled within-subjects study in a CAVE. While keeping a low PT so that the agent is not perceived as annoying, three strategies affecting the AT, namely fading, walking, and running, are evaluated by 40 subjects. The results indicate no clear preference for either behavior. Instead, the necessity of a better trade-off between a low AT and an agent’s realistic behavior is demonstrated.
Traditionally, experimental economics uses controlled and incentivized field and lab experiments to analyze economic behavior. However, investigating peer effects in the classic settings is challenging due to the reflection problem: Who is influencing whom?
To overcome this, we enlarge the methodological toolbox of these experiments by means of Virtual Reality. After introducing and validating a real-effort sorting task, we embed a virtual agent as peer of a human subject, who independently performs an identical sorting task. We conducted two experiments investigating (a) the subject’s productivity adjustment due to peer effects and (b) the incentive effects on competition. Our results indicate a great potential for Virtual-Reality-based economic experiments.
Computer-controlled, human-like virtual agents (VAs), are often embedded into immersive virtual environments (IVEs) in order to enliven a scene or to assist users. Certain constraints need to be fulfilled, e.g., a collision avoidance strategy allowing users to maintain their personal space. Violating this flexible protective zone causes discomfort in real-world situations and in IVEs. However, no studies on collision avoidance for small-scale IVEs have been conducted yet.
Our goal is to close this gap by presenting the results of a controlled user study in a CAVE. 27 participants were immersed in a small-scale office with the task of reaching the office door. Their way was blocked either by a male or female VA, representing their co-worker. The VA showed different behavioral patterns regarding gaze and locomotion.
Our results indicate that participants preferred collaborative collision avoidance: they expect the VA to step aside in order to get more space to pass while being willing to adapt their own walking paths.
Honorable Mention for Best Technote!
Computer-controlled virtual humans can serve as assistants in virtual scenes. Here, they are usually in an almost constant contact with the user. Nonetheless, in some applications assistants are required only temporarily. Consequently, presenting them only when needed, i.e, minimizing their presence time, might be advisable.
To the best of our knowledge, there do not yet exist any design guidelines for such agent-based support systems. Thus, we plan to close this gap by a controlled qualitative and quantitative user study in a CAVE-like environment.We expect users to prefer assistants with a low presence time as well as a low fallback time to get quick support. However, as both factors are linked, a suitable trade-off needs to be found. Thus, we plan to test four different strategies, namely fading, moving, omnipresent and busy. This work presents our hypotheses and our planned within-subject design.
Orientation and wayfinding in architectural Immersive Virtual Environments (IVEs) are non-trivial, accompanying tasks which generally support the users’ main task. World in Miniatures (WIMs)— essentially 3D maps containing a scene replica—are an established approach to gain survey knowledge about the virtual world, as well as information about the user’s relation to it. However, for largescale, information-rich scenes, scaling and occlusion issues result in diminishing returns. Since there typically is a lack of standardized information regarding scene decompositions, presenting the inside of self-contained scene extracts is challenging.
Therefore, we present an automatic WIM generation workflow for arbitrary, realistic in- and outdoor IVEs in order to support users with meaningfully selected and scaled extracts of the IVE as well as corresponding context information. Additionally, a 3D user interface is provided to manually manipulate the represented extract.
Virtual Agents (VAs) are embedded in virtual environments for two reasons: they enliven architectural scenes by representing more realistic situations, and they are dialogue partners. They can function as training partners such as representing students in a teaching scenario, or as assistants by, e.g., guiding users through a scene or by performing certain tasks either individually or in collaboration with the user. However, designing such VAs is challenging as various requirements have to be met. Two relevant factors will be briefly discussed in the talk: Collision Avoidance and Presence Strategies.
Experimental economics uses controlled and incentivized lab and field experiments to learn about economic behavior. By means of three examples, we illustrate how experiments conducted in immersive virtual environments emerge as a new methodological tool that can benefit behavioral economic research.
The knowledge of which places in a virtual environment are interesting or informative can be used to improve user interfaces and to create virtual tours. Viewpoint Quality Estimation algorithms approximate this information by calculating quality scores for viewpoints. However, even though several such algorithms exist and have also been used, e.g., in virtual tour generation, they have never been comparatively evaluated on virtual scenes. In this work, we introduce three new Viewpoint Quality Estimation algorithms, and compare them against each other and six existing metrics, by applying them to two different virtual scenes. Furthermore, we conducted a user study to obtain a quantitative evaluation of viewpoint quality. The results reveal strengths and limitations of the metrics on actual scenes, and provide recommendations on which algorithms to use for real applications.
Visualising volumetric medical images such as computed tomography and magnetic resonance imaging (MRI) on picture archiving and communication systems (PACS) clients is often achieved by image browsing in sagittal, coronal or axial views or three-dimensional (3D) rendering. This latter technique requires fine thresholding for MRI. On the other hand, computing virtual radiograph images, also referred to as digitally reconstructed radiographs (DRR), provides in a single two-dimensional (2D) image a complete overview of the 3D data. It appears therefore as a powerful alternative for MRI visualisation and preview in PACS. This study describes a method to compute DRR from T1-weighted MRI. After segmentation of the background, a histogram distribution analysis is performed and each foreground MRI voxel is labeled as one of three tissues: cortical bone, also known as principal absorber of the X-rays, muscle and fat. An intensity level is attributed to each voxel according to the Hounsfield scale, linearly related to the X-ray attenuation coefficient. Each DRR pixel is computed as the accumulation of the new intensities of the MRI dataset along the corresponding X-ray. The method has been tested on 16 T1-weighted MRI sets. Anterior-posterior and lateral DRR have been computed with reasonable qualities and avoiding any manual tissue segmentations.
Digital works of art are often created using some kind of modeling software, like Cinema4D. Usually they are presented in a non-interactive form, like large Diasecs, and can thus only be experienced by passive viewing. To explore alternative, more captivating presentation channels, we investigate the use of a CAVE virtual reality (VR) system as an immersive and interactive presentation platform in this paper. To this end, in a collaboration with an artist, we built an interactive VR experience from one of his existing works. We provide details on our design and report on the results of a qualitative user study.
Guided tours have been found to be a good approach to introducing users to previously unknown virtual environments and to allowing them access to relevant points of interest. Two important tasks during the creation of guided tours are the definition of views onto relevant information and their arrangement into an order in which they are to be visited. To allow a maximum of flexibility an interactive approach to these tasks is desirable. To this end, we present and evaluate two approaches to the mentioned interaction tasks in this paper. The first approach is a hybrid 2D/3D interaction metaphor in which a tracked tablet PC is used as a virtual digital camera that allows to specify and order views onto the scene. The second one is a purely 3D version of the first one, which does not require a tablet PC. Both approaches were compared in an initial user study, whose results indicate a superiority of the 3D over the hybrid approach.
Correspondence Analysis (CA) is frequently used to interpret correlations between categorical variables in the area of market research. To do so, coherences of variables are converted to a three-dimensional point cloud and plotted as three different 2D-mappings. The major challenge is to correctly interpret these plottings. Due to a missing axis, distances can easily be under- or overestimated. This can lead to a misclustering and misinterpretation of data and thus to faulty conclusions. To address this problem we present CAVIR, an approach for CA in Virtual Reality. It supports users with a virtual three-dimensional representation of the point cloud and different options to show additional information, to measure Euclidean distances, and to cluster points. Besides, the free rotation of the entire point cloud enables the CA user to always have a correct view of the data.
Correspondence Analysis (CA) is used to interpret correlations between categorical variables in the areas of social science and market research. To do so, coherences of variables are converted to a three-dimensional point cloud and plotted as several different 2D-mappings, each containing two axes. The major challenge is to correctly interpret these plottings. Due to a missing axis, distances can easily be under- or overestimated. This can lead to a misinterpretation and thus a misclustering of data.
To address this problem we present CAVIR, an approach for CA in Virtual Reality. It supports users with a three-dimensional representation of the point cloud and different options to show additional information, to measure Euclidean distances, and to cluster points. Besides, the motion parallax and a free rotation of the entire point cloud enable the CA expert to always have a correct view of the data.
Best Presentation Award!
A major challenge in Virtual Reality is to enable users to efficiently explore virtual environments, regardless of prior knowledge. This is particularly true for complex virtual scenes containing a huge amount of potential areas of interest. Providing the user convenient access to these areas is of prime importance, just like supporting her to orient herself in the virtual scene. There exist techniques for either aspect, but combining these techniques into one holistic system is not trivial. To address this issue, we present the Hierarchy Browser. It supports the user in creating a mental image of the scene. This is done by offering a well-arranged, hierarchical visual representation of the scene structure as well as interaction techniques to browse it. Additional interaction allows to trigger a scene manipulation, e.g. an automated travel to a desired area of interest. We evaluate the Hierarchy Browser by means of an expert walkthrough.