Torsten W. Kuhlen’s research while affiliated with RWTH Aachen University and other places

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Publications (27)


PASCAL - A Collaboration Technique Between Non-Collocated Avatars in Large Collaborative Virtual Environments
  • Article

March 2025

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10 Reads

IEEE Transactions on Visualization and Computer Graphics

David Gilbert

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Abhirup Bose

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Torsten W Kuhlen

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Collaborative work in large virtual environments often requires transitions from loosely-coupled collaboration at different locations to tightly-coupled collaboration at a common meeting point. Inspired by prior work on the continuum between these extremes, we present two novel interaction techniques designed to share spatial context while collaborating over large virtual distances. The first method replicates the familiar setup of a video conference by providing users with a virtual tablet to share video feeds with their peers. The second method called PASCAL (Parallel Avatars in a Shared Collaborative Aura Link) enables users to share their immediate spatial surroundings with others by creating synchronized copies of it at the remote locations of their collaborators. We evaluated both techniques in a within-subject user study, in which 24 participants were tasked with solving a puzzle in groups of two. Our results indicate that the additional contextual information provided by PASCAL had significantly positive effects on task completion time, ease of communication, mutual understanding, and co-presence. As a result, our insights contribute to the repertoire of successful interaction techniques to mediate between loosely- and tightly-coupled work in collaborative virtual environment


Overview of the primary and secondary tasks
The primary listening task was presented through headphones at 60 dB(A). In the visual secondary task, the numbers from 1–9, apart from 5, were presented. In the vibrotactile secondary task, two similar (short-short or long-long) or two different (short-long or long-short) vibration patterns were presented. If background noise was present, it was presented with an SNR of +10 dB (Experiments 1 and 2) or -3 dB (Experiment 3). Adapted from [12].
Timing structure of the primary and secondary tasks
The German texts in the primary listening task were presented through headphones, followed by questions presented on the laptop. Responses had to be typed on a keyboard. In the visual secondary task, digits from 1–9, except 5, were presented visually and participants had to respond whether the digit was less than or greater than 5. Responses were made using the two keys on the keyboard. In the vibrotactile secondary task, similar (short-short or long-long) or different (short-long or long-short) vibration patterns were presented via a game controller and participants had to identify whether the patterns were similar or different using two buttons on the controller.
Performance in the primary listening task across Experiments 1–3
Left: Listening task performance in single-task conditions as a function of acoustic condition (quiet, soft background noise, moderate background noise). Right: Listening task performance in dual-task conditions as a function of acoustic condition and secondary task (visual number-judgment task, vibrotactile pattern recognition task). The boxplots show the data distributions for primary task performance (proportion correct). The boxes represent the interquartile ranges, while the lines contained within the boxes represent the medians. ***p < .001, **p < .01, *p < .05.
Performance in the secondary tasks across Experiments 1–3
Secondary task performance as a function of acoustic condition (quiet, soft background noise, moderate background noise) and secondary task (visual number-judgment task, vibrotactile pattern recognition task). Left: Performance in the secondary tasks in single-task conditions. Right: Performance in the secondary tasks in dual-task conditions. The boxplots show the data distributions for secondary task performance (proportion correct). The boxes represent the interquartile ranges, while the lines contained within the boxes represent the medians. ***p < .001, *p < .05.
Reaction times in milliseconds in the secondary tasks across Experiments 1–3
Secondary task reaction times as a function of acoustic condition (quiet, soft background noise, moderate background noise) and secondary task (visual number-judgment task, vibrotactile pattern recognition task). Left: Reaction times in the secondary tasks in single-task conditions. Right: Reaction times in the secondary task in dual-task conditions. The boxplots illustrate the data distributions for the secondary task reaction times. The boxes represent the interquartile ranges, while the lines contained within the boxes represent the medians. ***p < .001, *p < .05.

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Exploring short-term memory and listening effort in two-talker conversations: The influence of soft and moderate background noise
  • Article
  • Full-text available

February 2025

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38 Reads

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1 Citation

Chinthusa Mohanathasan

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Cosima A. Ermert

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[...]

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Listening to conversations and remembering their content is a highly demanding task, especially in noisy environments. Previous research has mainly focused on short-term memory using simple cognitive tasks with unrelated words or digits. The present study investigates the listeners’ short-term memory and listening effort in conversations under different listening conditions, with and without soft or moderate noise. To this end, participants were administered a dual-task paradigm, including a primary listening task, in which conversations between two talkers were presented, and an unrelated secondary task. In Experiment 1, this secondary task was a visual number-judgment task, whereas in Experiments 2 and 3, it was a vibrotactile pattern recognition task. All experiments were conducted in a quiet environment or under continuous broadband noise. For the latter, the signal-to-noise ratio in Experiments 1 and 2 was +10 dB (soft-noise condition), while in Experiment 3 it was -3 dB (moderate-noise condition). In Experiments 1 and 2, short-term memory of running speech and listening effort were unaffected by soft-noise listening conditions. In Experiment 3, however, the moderate-noise listening condition impaired performance in the primary listening task, while performance in the vibrotactile secondary task was unaffected. This pattern of results could suggest that the moderate-noise listening condition, with a signal-to-noise ratio of -3 dB, required increased listening effort compared to the soft-noise and quiet listening conditions. These findings indicate that listening situations with moderate noise can reduce short-term memory of heard conversational content and increase listening effort, even when the speech signals remain highly intelligible.

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Game Engines for Immersive Visualization: Using Unreal Engine Beyond Entertainment

November 2024

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401 Reads

One core aspect of immersive visualization labs is to develop and provide powerful tools and applications that allow for efficient analysis and exploration of scientific data. As the requirements for such applications are often diverse and complex, the same applies to the development process. This has led to a myriad of different tools, frameworks, and approaches that grew and developed over time. The steady advance of commercial off-the-shelf game engines such as Unreal Engine has made them a valuable option for development in immersive visualization labs. In this work, we share our experience of migrating to Unreal Engine as a primary developing environment for immersive visualization applications. We share our considerations on requirements, present use cases developed in our lab to communicate advantages and challenges experienced, discuss implications on our research and development environments, and aim to provide guidance for others within our community facing similar challenges.


Figure 1: Listening experiment setup. The female ECA is employed in Experiment 1 and 2. The male ECA is employed only in Experiment 2.
Figure 2: Audiovisual angle incongruence in Experiment 1. The female ECA is displayed at an azimuth angle of 0 • on the horizontal plane at a distance of d = 2.5 m from the listener (blue). The possible virtual sound source positions (green) are at the azimuth angles 0 • , ±15 • , ±30 • , and ±60 • at the distance d.
Figure 3: One trial of the avVSR task. Graphic depiction of the trial phases Countdown, Stimulus presentation, Retention interval, and Recall phase over time. In the Recall phase, the cursor is visible as a red cross.
Figure 4: Questionnaire results of Experiment 1. The standard deviation SD difference between the HMD and the Monitor display conditions is shown for each question on the y-axis. Error bars indicate the 95% credible intervals. All questions were rated on a scale of 1 to 7, except for Q Inc, which was asked on a yes/no basis and is thus not displayed here.
Summary of pairwise comparisons between the audiovisual angle incongru- ences and display device combinations with Accuracy as the DV.
Audiovisual angle and voice incongruence do not affect audiovisual verbal short-term memory in virtual reality

October 2024

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61 Reads

Virtual reality (VR) environments are frequently used in auditory and cognitive research to imitate real-life scenarios, presumably enhancing state-of-the-art approaches with traditional computer screens. However, the effects of different display technologies on audiovisual processing remain underexplored. This study investigated how VR displayed with an head-mounted display (HMD) affects serial recall performance compared to traditional computer monitors, focusing on their effects on audiovisual processing in cognitive tasks. For that matter, we conducted two experiments with both an HMD and a computer monitor as display devices and two types of audiovisual incongruences: angle (Exp. 1) and voice (Exp. 2) incongruence. To quantify cognitive performance an audiovisual verbal serial recall (avVSR) task was developed where an embodied conversational agent (ECA) was animated to speak the target digit sequence. Even though subjective evaluations showed a higher sense of presence in the HMD condition, we found no effect of the display device on the proportion of correctly recalled digits. For the extreme conditions of angle incongruence in the computer monitor presentation the proportion of correctly recalled digits increased marginally, presumably due to raised attention, but the effect is likely too small to be meaningful. Response times were not affected by incongruences in either display device across both experiments. These findings suggest that the avVSR task is robust against angular and voice audiovisual incongruences, irrespective of the display device, at least for the conditions studied here. Hence, the study introduces the avVSR task in VR and contributes to the understanding of audiovisual integration.



Figure 4: In our user study, participants interacted with the developed system in a laboratory environment, which allowed us to monitor their behavior and reactions to the system under controlled conditions.
Virtual Reality as a Tool for Monitoring Additive Manufacturing Processes via Digital Shadows

September 2024

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48 Reads

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2 Citations

We present a data acquisition and visualization pipeline that allows experts to monitor additive manufacturing processes, in particular laser metal deposition with wire (LMD-w) processes, in immersive virtual reality. Our virtual environment consists of a digital shadow of the LMD-w production site enriched with additional measurement data shown on both static as well as handheld virtual displays. Users can explore the production site by enhanced teleportation capabilities that enable them to change their scale as well as their elevation above the ground plane. In an exploratory user study with 22 participants, we demonstrate that our system is generally suitable for the supervision of LMD-w processes while generating low task load and cybersickness. Therefore, it serves as a first promising step towards the successful application of virtual reality technology in the comparatively young field of additive manufacturing.


Boxplots illustrating the distribution of (a) primary task performance, (b) secondary task performance, and (c) response times in the secondary task for both single- and dual-tasking conditions, and as a function of voice quality. The color grey for N/A indicates that no speech was presented in this condition. ***p < 0.001, **p < 0.01.
Listening impression ratings for each voice quality and each questionnaire item. Rating scores range from 1 (not at all) to 5 (extremely). ***p < 0.001.
Participant immersed in the virtual seminar room with the virtual professor up front. The close-up of the professor is depicted here for illustrative purposes—it was not displayed on the HMD.
Flow chart of the experimental procedure.
A lecturer’s voice quality and its effect on memory, listening effort, and perception in a VR environment

May 2024

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144 Reads

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4 Citations

Many lecturers develop voice problems, such as hoarseness. Nevertheless, research on how voice quality influences listeners’ perception, comprehension, and retention of spoken language is limited to a small number of audio-only experiments. We aimed to address this gap by using audio-visual virtual reality (VR) to investigate the impact of a lecturer’s hoarseness on university students’ heard text recall, listening effort, and listening impression. Fifty participants were immersed in a virtual seminar room, where they engaged in a Dual-Task Paradigm. They listened to narratives presented by a virtual female professor, who spoke in either a typical or hoarse voice. Simultaneously, participants performed a secondary task. Results revealed significantly prolonged secondary-task response times with the hoarse voice compared to the typical voice, indicating increased listening effort. Subjectively, participants rated the hoarse voice as more annoying, effortful to listen to, and impeding for their cognitive performance. No effect of voice quality was found on heard text recall, suggesting that, while hoarseness may compromise certain aspects of spoken language processing, this might not necessarily result in reduced information retention. In summary, our findings underscore the importance of promoting vocal health among lecturers, which may contribute to enhanced listening conditions in learning spaces.


Game Engines for Immersive Visualization: Using Unreal Engine Beyond Entertainment

March 2024

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99 Reads

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5 Citations

Presence Teleoperators & Virtual Environments

One core aspect of immersive visualization labs is to develop and provide powerful tools and applications that allow for efficient analysis and exploration of scientific data. As the requirements for such applications are often diverse and complex, the same applies to the development process. This has led to a myriad of different tools, frameworks, and approaches that grew and developed over time. The steady advance of commercial off-the-shelf game engines such as Unreal Engine has made them a valuable option for development in immersive visualization labs. In this work, we share our experience of migrating to Unreal Engine as a primary developing environment for immersive visualization applications. We share our considerations on requirements, present use cases developed in our lab to communicate advantages and challenges experienced, discuss implications on our research and development environments, and aim to provide guidance for others within our community facing similar challenges.




Citations (17)


... The heard text recall (HTR 3,8,34 ) served as the primary listening task. The auditory stimuli were spoken coherent texts, each describing three generations of a family (grandparents, parents, and children), considering different aspects such as the family members' age, professions, hobbies, and relationships with one another. ...

Reference:

Listening to two-talker conversations in quiet settings: the role of listeners’ cognitive processing capabilities for memory and listening effort
Exploring short-term memory and listening effort in two-talker conversations: The influence of soft and moderate background noise

... The process consists of a laser beam melting a metallic wire as it is laid onto a substrate. This technique is known as Laser Metal Deposition with wire (LMD-w) [30]. In this process, a metal alloy wire is typically fed into the laser beam at a specified position. ...

Virtual Reality as a Tool for Monitoring Additive Manufacturing Processes via Digital Shadows

... Fintor et al. [11] addressed a research gap by investigating listeners' short-term memory in a listening task that was more complex and closer to real life (cp. [12,13]). In two experiments, memory for running speech was measured by asking participants to answer content-related questions immediately after listening to a two-talker conversation in quiet conditions. ...

A lecturer’s voice quality and its effect on memory, listening effort, and perception in a VR environment

... The avVSR task was configured for both HMD and computer monitor presentations and implemented in Unreal Engine (Epic Games, v4.27) using the following plugins: the StudyFramework plugin [34] (v4.26), which handles the data logging and experiment procedure, the RWTH VR Toolkit plugin [35] (v4.27) for basic VR interaction, and the Character plugin (v4.27) for ECA animation. In the HMD condition, the scene was presented using an HTC Vive Pro Eye (dual AMOLED screens with 3.5 ′′ diagonal display, resolution 1440 × 1600 pixels per eye) and one HTC Vive controller. ...

StudyFramework: Comfortably Setting up and Conducting Factorial-Design Studies Using the Unreal Engine
  • Citing Conference Paper
  • March 2024

... The StudyFramework was already successfully used in 14 experiments (e.g., [7,8,[13][14][15]) and successively updated and improved in that process. All developers of these studies (if not the first author of this paper) were asked to fill out a short subjective evaluation ques-tionnaire after conducting their respective study. ...

Audiovisual Coherence: Is Embodiment of Background Noise Sources a Necessity?
  • Citing Conference Paper
  • March 2024

... In practical terms, the same actions performed in a different environment would not authenticate the user, as the framework would identify that the physical environment differs from the one used at enrolment time. Rupp et al. (2024) created a novel gesture-based authentication system that leverages the interaction with virtual avatars. The VR user is immersed in a virtual office room, populated by virtual agents that act as interaction partners. ...

Authentication in Immersive Virtual Environments through Gesture-Based Interaction with a Virtual Agent

... García et al. [53] described a VR-based interface for a "virtual cockpit" for the remote operation of underwater robots. Schroepfer et al. [54] presented a multi-medium system with a VR interface for controlling underwater and above water crawlers, drones, and AUVs. ...

Navigating Real-World Complexity: A Multi-Medium System for Heterogeneous Robot Teams and Multi-Stakeholder Human-Robot Interaction
  • Citing Conference Paper
  • March 2024

... However, widgets can easily occlude relevant parts of the scene and require the user to focus parts of their attentional resources on their interpretation rather than the actual content. As a result, prior work also investigated more embedded forms of visual guidance such as the playback of a spatial recording in which another user interacts with the environment [14,60] or the use of intelligent virtual agents that are programmed to guide the user through the virtual environment [4,41]. In our work, we make use of guidance cues only to indicate how the user should rotate to face the correct direction, which is a mechanism often employed in cinematic virtual reality (see [51] for a survey). ...

Wayfinding in immersive virtual environments as social activity supported by virtual agents

Frontiers in Virtual Reality

... The StudyFramework was already successfully used in 14 experiments (e.g., [7,8,[13][14][15]) and successively updated and improved in that process. All developers of these studies (if not the first author of this paper) were asked to fill out a short subjective evaluation ques-tionnaire after conducting their respective study. ...

Whom Do You Follow?: Pedestrian Flows Constraining the User's Navigation during Scene Exploration
  • Citing Conference Paper
  • December 2023