Publications

@inproceedings{klank2026,

title = {Testing before Building? Strengths and Weaknesses of VR-Based Usability Testing of a Gesture Interface},

author = {R Klank and F Heinrich and D Schott and C Hansen and F Joeres },

year  = {2026},

date = {2026-11-16},

urldate = {2026-11-16},

booktitle = {ACM Symposium on Virtual Reality Software and Technology (VRST)},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{schwadtke2026,

title = {Striving for Stability: Evaluating the Feasibility of Dynamic Balance Skills Across the Reality–Virtuality Continuum},

author = {A Schwadtke and S Pastel and M Kunz and P Müller and R Braun-Dullaeus and C Hansen and K Witte and D Schott},

year  = {2026},

date = {2026-10-07},

urldate = {2026-10-07},

booktitle = {IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct)},

journal = {ISMAR 2026 Posters},

abstract = {Dynamic balance assessment is important in sports and rehabilitation. Mixed Reality (MR) offers new opportunities for portable diagnostics. This study investigated whether the standardized YBalance Test Lower Quarter (YBT) can be administered in MR nvironments. Twenty-four participants performed the YBT in a real environment (RE), Augmented Reality (AR), Augmented Virtuality (AV), and Virtual Environment (VE) on two test days. Despite higher perceived demands, MR-based YBT outcomes were comparable to RE across all MR conditions (p > 0.05), with good to-moderate test-retest reliability. These findings support the feasibility of MR-based YBT assessment for diagnostics, warranting further validation.},

howpublished = {ISMAR Posters},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{klus2026,

title = {Curriculare Akzeptanz von XR in der medizinischen Ausbildung: Einfluss von XR-Erleben, Wissenszuwachs und Vorerfahrungen in einer Pilotstudie mit Medizinstudierenden},

author = {C Klus and J Bosch and C Ludwig and M Kunz and C Hansen and D Stoevesandt and R Braun-Dullaeus and D Schott},

url = {https://series.publisso.de/en/conferences/gma2026/26gma022},

doi = {10.3205/26gma022},

year  = {2026},

date = {2026-09-17},

urldate = {2026-09-17},

booktitle = {Jahrestagung der Gesellschaft für Medizinische Ausbildung (GMA)},

address = {Dresden, Germany},

note = {DocV-0404},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schwenderling2026,

title = {Augmented Reality Training of Attention Allocation in Medical Dual-Task Learning Applications},

author = {L Schwenderling and M Schotte and F Joeres and F Heinrich and C Hansen},

year  = {2026},

date = {2026-08-31},

urldate = {2026-08-31},

booktitle = {ACM International Conference on Mobile Human-Computer Interaction 2026 (MobileHCI 2026)},

journal = {The ACM International Conference on Mobile Human-Computer Interaction 2026 (MobileHCI 2026)},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{nokeyc,

title = {Usability Assessment of Low-cost Sensor Kits for Educational Air Quality Sensing},

author = {V Batz and P Cavkovski and JM Loebel and P Lameski and V Trajkovik and C Hansen and MA Herzog},

url = {https://link.springer.com/chapter/10.1007/978-3-032-30542-8_2},

doi = {10.1007/978-3-032-30542-8_2},

year  = {2026},

date = {2026-07-07},

urldate = {2026-07-07},

booktitle = {HCI International (HCII), Lecture Notes in Computer Science},

volume = {16731},

pages = {23-42},

abstract = {This study assesses the usability of the Pulse.Eco Combo Cube v3 particulate‑matter sensor kit and examines its suitability as an educational toolkit for citizen science in schools. The goal is to develop a low-cost DIY sensor kit that can be used for participatory data collection in school MAKER workshops, thereby promoting environmental awareness and environmentally conscious behavior among students. We further show that our design-thinking workflow generalizes to other educational sensing toolkits.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schreiter2026,

title = {Touch-Based Interaction and Clutching Strategies in Collaborative Robotics across Task Types},

author = {J Schreiter and P Pandi and R Klank and C Hansen and F Heinrich},

year  = {2026},

date = {2026-06-30},

urldate = {2026-06-30},

booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{esmaeili2026,

title = {When Tissue Speaks: Vibroacoustic Monitoring of Tissue Response during Electrosurgery},

author = {N Esmaeili and R Urrutia and D Espejo and A Boese and P Horvath and C Hansen and J Hagenah and A Illanes},

year  = {2026},

date = {2026-06-19},

urldate = {2026-06-19},

publisher = {Medical Image Computing and Computer Assisted Intervention (MICCAI)},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{urrutia2026,

title = {Where Is the Needle Tip? Vibroacoustic Sensing Reveals Hidden Needle-Tissue Transitions During Ultrasound Guidance},

author = {R Urrutia and N Esmaeili and S Matinfar and A Boese and N Davaris and C Arens and C Hansen and A Illanes},

year  = {2026},

date = {2026-06-18},

urldate = {2026-06-18},

issuetitle = {Medical Image Computing and Computer Assisted Intervention (MICCAI)},

publisher = {Medical Image Computing and Computer Assisted Intervention (MICCAI)},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{illanes2026,

title = {Ex Vivo Tissue Differentiation Using Vibroacoustic Sensing at the Proximal End of Laparoscopic Instruments},

author = {A Illanes and N Esmaeili and R Urrutia and D Espejo and J Hagenah and C Hansen and A Boese},

year  = {2026},

date = {2026-06-17},

urldate = {2026-06-17},

booktitle = { IEEE Engineering in Medicine and Biology Society (EMBC)},

keywords = {},

pubstate = {forthcoming},

tppubtype = {inproceedings}

}

@inproceedings{weiss2026,

title = {Bridging the Reality Gap: Immersive VR Simulation for Enhancing Stress Resilience in Medical Students},

author = {S Weiss and L Hanke and E Schröder and M Weinberg and T Dicks and C Castell and M Wessels and H Hecht and P Dietz and T Huber and C Hansen},

doi = {10.1109/VRW70859.2026.00156},

year  = {2026},

date = {2026-05-01},

urldate = {2026-05-01},

booktitle = {IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

journal = {2026 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = { 814-818},

abstract = {Medical students often face a “reality gap” between theory and clinical practice, leading to burnout. We present a system to induce stress as first step for later stress resilience trainings through immersive simulations of clinical conflicts. Based on a survey of 374 professionals, we developed four scenarios targeting stressors like “conflict with superiors” and “time pressure,” utilizing realistic locations and NPCs. Our framework uses a Meta Quest 3 and a custom Android app for real-time experimenter control. To overcome static training limitations, we explore local Large Language Models (LLMs) for generative NPC behavior. We detail a work-in-progress evaluation protocol using physiological measures (HR, HRV, BF) and questionnaires, providing a scalable framework for medical stress inoculation training.},

howpublished = { IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{heinrich2026b,

title = {Towards Simulating Projector-Based Augmented Reality in Virtual Reality for Interventional Evaluation},

author = {F Heinrich and L Schülke and M Kohpeiss and D Schott and C Hansen},

doi = {10.1109/VRW70859.2026.00145},

year  = {2026},

date = {2026-05-01},

urldate = {2026-05-01},

booktitle = {IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {758-763},

publisher = {IEEE},

abstract = {Evaluating projector-based augmented reality (AR) systems for interventional guidance in clinical environments is costly, timeconsuming, and subject to strict safety constraints. We present a virtual reality (VR)–based simulation approach that enables earlystage evaluation of projector-based AR guidance concepts without requiring physical hardware. A virtual interventional room was created based on a real CT suite and combined with hand-tracked needle interaction and a simulated projector-based guidance visualization. We evaluated the system in a virtual needle insertion task using performance metrics as well as established presence and user experience questionnaires. Results indicate high perceived presence and user experience, while revealing limitations in absolute insertion accuracy. Our initial findings suggest that VR-based simulation is a promising tool for early interventional evaluation of projector-based AR concepts, particularly for usability and user experience studies.},

howpublished = { IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Sabir2026,

title = {Evaluation of a State-Aware conversational AI agent for Immersive Anatomy Education},

author = {A Sabir and E Ringler and J Mandel and C Hansen and D Schott},

url = {https://ieeexplore.ieee.org/document/11489889},

doi = {10.1109/VRW70859.2026.00151},

year  = {2026},

date = {2026-04-30},

urldate = {2026-04-30},

booktitle = {IEEE Conference on Virtual Reality and 3D User Interfaces (VRW)},

pages = {790-794},

abstract = {The dynamic 3D morphology and temporal complexity of embryonic heart development make it difficult to comprehend. We introduce Reinheart, a conversational AI tutor for anatomy education that is state-aware and integrated into a mixed-reality learning environment. The AI tutor uses OpenAI services to provide voice-based tutoring in real-time with interactive 3D visualization. Using a mixed-method analysis, ten anatomy experts assessed pedagogical performance, usability, and trust. The results indicated high ease-of-use and positive social presence, while qualitative feedback revealed limited uncertainty in communication and instability in challenge tasks. Experts supported the tutor’s potential for conceptual reinforcement and guided exploration. To improve contextual reasoning and instructional reliability in MR anatomy learning, future work should extend this framework with domain-specific, uncertainty-aware AI.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Schreiter2026,

title = {Exploring Augmented Reality Visualizations for Communicating Robot Intent in Robotic Ultrasound},

author = {J Schreiter and M Tan and R Klank and C Hansen and F Joeres},

doi = {10.1109/VRW70859.2026.00142},

year  = {2026},

date = {2026-04-30},

urldate = {2026-04-30},

booktitle = {IEEE Conference on Virtual Reality and 3D User Interfaces (VRW)},

pages = {739-744},

abstract = {Working safely in close proximity to robots, such as during robot-assisted medical procedures, requires communication of robot intent. We investigated how augmented reality (AR) visualizations can convey robot poses, trajectories, and motion progress by comparing several designs in a laboratory study with six participants. Results showed that arrow-based visualizations are preferred for representing robot poses and trajectories. Explicit progress displays were perceived as clearer and safer, but trajectory-based cues were preferred overall due to reduced distraction. Overall, visualizations that conveyed essential information while minimizing occlusion were rated most valuable. This work contributes an initial perspective towards structuring the AR design space for human-robot interaction with a robotic arm, illustrated through the example of robotic ultrasound},

howpublished = { IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{holonote,

title = {HoloNote: Exploring Augmented Reality Notifications for Ergonomic Feedback in Laparoscopic Training},

author = {F Heinrich and T Mielke and R Klank and F Ortega and C Hansen and T Huber and F Huettl},

url = {https://dl.acm.org/doi/10.1145/3772363.3799086},

doi = {10.1145/3772363.3799086},

year  = {2026},

date = {2026-04-13},

urldate = {2026-03-01},

booktitle = {Extended Abstracts of the CHI Conference on Human Factors in Computing Systems (CHI EA)},

number = {368},

pages = {1-6},

publisher = {Association for Computing Machinery},

abstract = {Laparoscopic surgery is a physically demanding task that can lead to ergonomic strain. While notification-based approaches have been used to support ergonomics in other domains, their application in laparoscopic surgery remains limited.

Therefore, an augmented reality (AR) notification concept was implemented using lightweight optical see-through AR glasses, examining their suitability for laparoscopic training.

A pilot study with ten surgeons was conducted using a laparoscopic simulator, where participants performed a stitching and knot-tying task with and without AR-based notifications.

All participants were able to complete the tasks while wearing the AR glasses. While task completion times were longer in the AR condition, no conclusive differences in perceived workload were observed. User experience and wearing comfort were rated positively, whereas the notifications were perceived as useful but not consistently effective. The findings suggest that lightweight AR glasses are a feasible platform for ergonomic feedback in laparoscopic training and motivate further investigation.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{nokeyd,

title = {Enhancing Gesture-Based Human–Robot Interaction: Investigating the Role of Force Automation},

author = {T Mielke and M Georgiades and O Grosser and M Pech and C Hansen and F Heinrich},

doi = {10.1145/3757279.3785568},

year  = {2026},

date = {2026-03-16},

urldate = {2026-03-16},

booktitle = {ACM/IEEE International Conference on Human-Robot Interaction (HRI)},

pages = {619-628},

abstract = {Directly controlling robot motion through human–robot interaction enables the integration of human expertise into robot control. However, this requires efficient interaction methods. While previous work has shown that hand gestures offer potential for natural control, the lack of haptic feedback remains a key challenge. One solution is partial automation, in which the contact force is autonomously controlled. We implemented force automation enhanced gesture control, as well as the state-of-the-art baseline of hand-guiding, to systematically investigate hand gesture interaction for robot control. A user study (n=28) was conducted to investigate the efficiency and workload of these interaction concepts. As the interaction method efficiency may depend on task demands, two tasks with different precision requirements were evaluated in the context of robotic ultrasound. The results indicate that force automation significantly reduces perceived workload and task duration when using hand gestures. Moreover, gesture-based interaction can match the efficiency of hand-guiding for broad tasks and even outperform it in precise tasks. These findings highlight the potential of gesture-based interaction for robot control, particularly when the absence of haptic feedback is compensated by partial automation.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{mielke_gesturing_2025,

title = {Gesturing Towards Efficient Robot Control: Exploring Sensor Placement and Control Modes for Mid-Air Human-Robot Interaction},

author = {T Mielke and F Heinrich and C Hansen},

doi = {10.1109/ICRA55743.2025.11127519},

year  = {2025},

date = {2025-09-02},

urldate = {2025-09-02},

booktitle = {2025 IEEE International Conference on Robotics and Automation (ICRA)},

publisher = {IEEE},

abstract = {While collaborative robots effectively combine robotic precision with human capabilities, traditional control methods such as button presses or hand guidance can be slow and physically demanding. This has led to an increasing interest in natural user interfaces that integrate hand gesturebased interactions for more intuitive and flexible robot control. Therefore, this paper systematically explores mid-air robot control by comparing position and rate control modes with different state-of-the-art and novel sensor placements. A user study was conducted to evaluate each combination in terms of accuracy, task duration, perceived workload, and physical exertion. Our results indicate that position control is more efficient than rate control. Traditional desk-mounted sensors can provide a good balance between accuracy and comfort. However, robot-mounted sensors are a viable alternative for short-term, accurate control with less spatial requirements. Legmounted sensors, while comfortable, pose challenges to handeye coordination. Based on these findings, we provide design implications for improving the usability and comfort of midair human-robot interaction. Future research should extend this evaluation to a wider range of tasks and environments.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{mielke_enhancing_2025,

title = {Enhancing AR-to-Robot Registration Accuracy: A Comparative Study of Marker Detection Algorithms and Registration Parameters},

author = {T Mielke and F Heinrich and C Hansen},

doi = {10.1109/ICRA55743.2025.11128039},

year  = {2025},

date = {2025-09-02},

urldate = {2025-09-02},

booktitle = {2025 IEEE International Conference on Robotics and Automation (ICRA)},

publisher = {IEEE},

abstract = {Augmented Reality (AR) offers potential for enhancing human-robot collaboration by enabling intuitive interaction and real-time feedback. A crucial aspect of AR-robot integration is accurate spatial registration to align virtual content with the physical robotic workspace. This paper systematically investigates the effects of different tracking techniques and registration parameters on AR-to-robot registration accuracy, focusing on paired-point methods. We evaluate four marker detection algorithms - ARToolkit, Vuforia, ArUco, and retroreflective tracking - analyzing the influence of viewing distance, angle, marker size, point distance, distribution, and quantity. Our results show that ARToolkit provides the highest registration accuracy. While larger markers and positioning registration point centroids close to target locations consistently improved accuracy, other factors such as point distance and quantity were highly dependent on the tracking techniques used. Additionally, we propose an effective refinement method using point cloud registration, significantly improving accuracy by integrating data from points recorded between registration locations. These findings offer practical guidelines for enhancing AR-robot registration, with future work needed to assess the transferability to other AR devices and robots.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Joeres.2025,

title = {The necessity of parallel needle placement for tumor ablation using irreversible electroporation: a myth?},

author = {F Joeres and T Paetz and C Hansen and A Schenk},

url = {https://link.springer.com/article/10.1007/s11548-025-03373-6},

doi = {10.1007/s11548-025-03373-6},

year  = {2025},

date = {2025-05-29},

urldate = {2025-05-29},

booktitle = {CARS 2025—Computer Assisted Radiology and Surgery Proceedings of the 39th International Congress and Exhibition Berlin, Germany, June 17–20, 2025

},

pages = {90–91},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schwenderling_teach_2025,

title = {Teach Me Where to Look: Dual-task Attention Training in Augmented Reality},

author = {L Schwenderling and M Schotte and F Joeres and F Heinrich and L Hanke and F Huettl and T Huber and C Hansen},

url = {https://dl.acm.org/doi/10.1145/3706599.3720198},

doi = {10.1145/3706599.3720198},

isbn = {979-8-4007-1395-8},

year  = {2025},

date = {2025-04-01},

urldate = {2025-04-01},

booktitle = {Proceedings of the Extended Abstracts of the CHI Conference on Human Factors in Computing Systems},

pages = {1–8},

publisher = {ACM},

address = {Yokohama Japan},

abstract = {Regular eye contact is essential in medicine to recognize signs of pain. However, it is difficult to remember this during training as attention is tied up in learning. While augmented reality (AR) has shown promising results for medical education, there is no training for attention allocation yet. Therefore, three auditory and three visual attention guidance tools in AR are evaluated for their use in medical dual-task training settings. In expert reviews with six participants in human-computer interaction and medical didactics, advantages, disadvantages, and refinements for the cues were developed. For visual cues, an overt but less occluding cue was preferred for constant visibility of the primary task. A more diegetic cue design was proposed for the auditory cues to use a patient simulation as a reminder of the regular face glance. In general, several cues were found to be suitable for gaze guidance training, requiring only minor changes for improvement.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{mielke_virtual_2025,

title = {Virtual Studies, Real Results? Assessing the Impact of Virtualization on Human-Robot Interaction},

author = {T Mielke and M Allgaier and D Schott and C Hansen and F Heinrich},

url = {https://dl.acm.org/doi/10.1145/3706599.3719724},

doi = {10.1145/3706599.3719724},

isbn = {979-8-4007-1395-8},

year  = {2025},

date = {2025-04-01},

urldate = {2025-04-01},

booktitle = {Proceedings of the Extended Abstracts of the CHI Conference on Human Factors in Computing Systems},

pages = {1–8},

publisher = {ACM},

address = {Yokohama Japan},

abstract = {Extended Reality (XR) shows potential for human-centered evaluation of real-world scenarios and could improve efficiency and safety in robotic research. However, the validity of XR Human-Robot Interaction (HRI) studies remains underexplored. This paper investigates the transferability of HRI studies across virtualization levels for three tasks. Our results indicate XR study validity is task-specific, with task virtualization as a key influencing factor. Partially virtualized settings with virtual tasks and a real robot, as well as fully virtualized setups with a simulated robot, yielded results comparable to real setups for pick-and-place and robotic ultrasound. However, for precision-dependent peg-in-hole, differences were observed between real and virtualized conditions regarding completion time, perceived workload, and ease. Demonstrating the task dependency of XR transferability and comparing virtualization levels, our work takes an important step in assessing XR study validity. Future work should isolate factors affecting transferability and assess relative validity in the absence of absolute validity.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{heinrich_you_2025,

title = {Do You See What I See? Evaluating Relative Depth Judgments Between Real and Virtual Projections},

author = {F Heinrich and D Schott and L Schwenderling and C Hansen},

url = {https://doi.org/10.1145/3706599.3720157},

doi = {10.1145/3706599.3720157},

isbn = {979-8-4007-1395-8},

year  = {2025},

date = {2025-04-01},

urldate = {2025-04-01},

booktitle = {Proceedings of the Extended Abstracts of the CHI Conference on Human Factors in Computing Systems},

pages = {1–8},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {CHI EA '25},

abstract = {Projector-based augmented reality (AR) is promising in different domains with less issues in discomfort or shortage of space. However, due to limitations like high costs and cumbersome calibration, this AR modality remains underused. To address this problem, a stereoscopic projector-based AR simulation was implemented for a cost-effective video see-through AR headset. To evaluate the validity of this simulation, a relative depth judgment experiment was conducted to compare this method with a physical projection system. Consistent results suggest that a known interaction effect between visualization and disparity mode could be successfully reproduced using both the physical projection and the virtual simulation. In addition, first findings indicate that there are no significant differences between these projection modalities. The results indicate that other perception-related effects observed for projector-based AR may also be applicable to virtual projection simulations and that future findings determined using only these simulations may also be applicable to real projections.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{allgaier_impact_2025,

title = {Impact of Input and Output Devices on a Virtual Ultrasound Training},

author = {M Allgaier and E Dangszat and F Huettl and L Hanke and T Huber and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/10972939/},

doi = {10.1109/VRW66409.2025.00191},

isbn = {979-8-3315-1484-6},

year  = {2025},

date = {2025-03-01},

urldate = {2025-03-01},

booktitle = {2025 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {937–941},

publisher = {IEEE},

address = {Saint Malo, France},

abstract = {Performing ultrasound requires mental skills that have to be trained hands on. Virtual simulations can be employed to provide novice surgeons with a safe training environment prior to performing ultrasound on the patient. For both input and output there is a wide range of devices that are used in existing ultrasound simulations. Because the devices have their limitations and benefits regarding realism, costs, and access, we compared three technical setups: desktop with mouse interaction, desktop with a haptic device, and virtual reality with a haptic device. In a user study with 19 participants we investigated the usability and assessed qualitative user feedback in a semi-structured interview. Significant differences regarding usability and training time were found between both versions with the haptic device and the desktop with mouse version. Based on the feedback, using a haptic device seems to be more relevant than the two output devices in this training case.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{herbrich_prototype_2025,

title = {Prototype development of a cross-reality digital twin ecosystem: the web, open source and open data},

author = {W Herbrich and P Zittlau and F Joeres and C Hansen},

url = {https://ieeexplore.ieee.org/abstract/document/10972895},

doi = {10.1109/VRW66409.2025.00100},

year  = {2025},

date = {2025-03-01},

urldate = {2025-03-01},

booktitle = {2025 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {459–462},

abstract = {This work contributes to a broader initiative aimed at transforming a former industrial port area into a dynamic Knowledge Transfer Space (KTS). To support this transformation, we explore the development of a cross-reality (CR) digital twin of the port area, which integrates user interfaces with varying degrees of virtuality. We evaluate different web technologies, focusing on the balance between accessibility, immersion, scalability, and performance. By comparing client-side rendering with pixel streaming approaches, we aim to identify suitable solutions for prototyping a CR digital twin ecosystem. The development of a prototype is ongoing, based on a client-side rendering approach. The outcomes contribute to developing an open and transferable CR digital twin applicable to similar urban projects in other cities.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schreiter_exploring_2025,

title = {Exploring Interaction Concepts for the Manipulation of a Collaborative Robot: A Comparative Study},

author = {J Schreiter and T Mielke and M Georgiades and M Pech and C Hansen and F Heinrich},

url = {https://ieeexplore.ieee.org/document/10974113},

year  = {2025},

date = {2025-01-01},

urldate = {2025-01-01},

booktitle = {ACM/IEEE International Conference on Human-Robot Interaction},

pages = {55–64},

publisher = {IEEE Press},

address = {Melbourne, Australia},

series = {HRI '25},

abstract = {Robotic systems have the potential to enhance a wide range of domains, such as medical workflows, by automating individual steps of complex processes. However, human-robot interaction (HRI) is of critical importance, as effective collaboration between humans and robots is essential even in highly automated environments. Recent research has predominantly focused on the development of interaction methods rather than systematically comparing existing approaches. Therefore, we conducted a user study (n=20) to compare different HRI concepts for end effector manipulation combined with clutching mechanisms for manipulation activation in an alignment task using the example of robotic ultrasound (US). Manipulation methods included hand-guiding, teleoperation, and touchless interaction, while clutching mechanisms were realized through hand, voice, and foot interaction. The results indicate advantages of hand-guiding for manipulation. While no significant differences were observed between clutching mechanisms, strong evidence suggests comparable performance across these modalities. Notably, significant interaction effects on perceived workload reveal that the optimal clutching mechanism depends on the selected manipulation technique. This work underscores the critical importance of selecting appropriate HRI concepts and understanding the dependencies of manipulation techniques with clutching mechanisms. While our study included the usage of a robotic US, the insights gained are broadly transferable across various domains involving robotic manipulation tasks in human-robot collaboration.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bashkanov_augmenting_2025,

title = {Augmenting Prostate MRI Dataset with Synthetic Volumetric Images from Zone-Conditioned Diffusion Generative Model},

author = {O Bashkanov and M Rak and L Engelage and C Hansen},

editor = {A Mukhopadhyay and I Oksuz and S Engelhardt and D Merhof and Y Yuan},

doi = {10.1007/978-3-031-72744-3_16},

isbn = {978-3-031-72744-3},

year  = {2025},

date = {2025-01-01},

urldate = {2025-01-01},

booktitle = {Deep Generative Models},

pages = {160–168},

publisher = {Springer Nature Switzerland},

address = {Cham},

abstract = {The need for artificial intelligence (AI)-driven computer-assist ed diagnosis (CAD) tools drives up the demand for large high-quality datasets in medical imaging. However, collecting the necessary amount of data is often impractical due to patient privacy concerns or restricted time for medical annotation. Recent advances in generative models in medical imaging with a focus on diffusion-based techniques could provide realistic-looking synthetic samples as a supplement for real data. In this work, we study whether synthetic volumetric MRIs generated by the diffusion model can be used to train downstream models, e.g., semantic segmentation. We can create an arbitrarily large dataset with ground truth by conditioning the diffusion model with a segmentation mask. Thus, the additional synthetic data can be used to control the dataset diversity. Experiments revealed that downstream tasks profit from additional synthetic data. However, the effect will eventually diminish when sufficient real samples are available. We showcase the strength of the synthetic data and provide practical recommendations for using the generated data in zonal prostate segmentation.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{batz2025enhancing,

title = {Enhancing Public Awareness of Air Quality: Evaluating Communication Strategies and Design Prototypes Using a Design-Based Implementation Research Approach},

author = {V Batz and VB Liedtke and P Lameski and V Trajkovik and S Hußlein and C Hansen and MA Herzog},

url = {https://link.springer.com/chapter/10.1007/978-3-031-93221-2_1},

year  = {2025},

date = {2025-01-01},

urldate = {2025-01-01},

booktitle = {International Conference on Human-Computer Interaction},

pages = {3–25},

organization = {Springer},

abstract = {Despite the health risks associated with air pollution and the availability of data, public awareness of air quality remains limited. This paper examines communication strategies to enhance awareness in Germany and North Macedonia. Using the Design-Based Implementation Research approach, literature reviews, stakeholder interviews and surveys were conducted with 307 participants to identify knowledge gaps and effective methods.



Three citizen workshops led to the development and evaluation of five design prototypes, including an interactive installation (“Pollution Booth”), a VR application (“Visible Particulate Matter”), and a gamified learning experience (“End Game”). These prototypes addressed information accessibility, data representation, and environmentally conscious behavior. The results show that region-specific communication, interactive designs, and passive information methods in public spaces significantly improve the perception and understanding of air pollution data. Gamified approaches, such as the “End Game” prototype, were particularly effective in educating children about air pollution.



Thirty-two requirements for effective educational strategies were identified, including simplified data visualization, reduced content, and personalized information. The findings highlight the importance of local and personalized approaches, as well as methods for collective knowledge sharing, in promoting awareness and environmentally friendly behavior. Future work should further explore the long-term engagement and sustainable impact of such communication strategies.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{joeres_concept_2024,

title = {Concept development of a cross-reality ecosystem for urban knowledge transfer spaces},

author = {F Joeres and P Zittlau and W Herbrich and F Heinrich and G Rose and C Hansen},

url = {https://ieeexplore.ieee.org/abstract/document/10765174},

doi = {10.1109/ISMAR-Adjunct64951.2024.00043},

year  = {2024},

date = {2024-10-01},

urldate = {2024-10-01},

booktitle = {2024 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct)},

pages = {166–169},

abstract = {This paper presents the development of a cross-reality (CR) ecosystem designed for an urban knowledge transfer space (KTS) in a post-industrial urban environment. The project is part of a larger initiative aimed at transforming a former industrial river port into a dynamic KTS, facilitating interactions between scientific, commercial, residential, and cultural stakeholders. Our research explores the potential of multimodal mixed reality (XR) technologies to enhance engagement with the content and stakeholders of the KTS. Through a three-phase process, we identified key stakeholders and their target audiences, selected appropriate XR technologies, and developed initial use cases that integrate web applications, mobile augmented reality (AR), and XR head-mounted displays. The preliminary findings indicate that these technologies can effectively cater to diverse user groups, providing different levels of virtuality and interaction. However, challenges remain, particularly in stakeholder engagement and the evolving nature of the KTS initiative. Ongoing work includes the development of a Web-XR-based prototype, which will be iteratively refined to better meet user needs and adapt to future technological advancements. This research contributes to the understanding of how CR technologies can be employed in urban transformation processes, offering insights into the design of flexible and scalable CR ecosystems.},

note = {ISSN: 2771-1110},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schwenderling_novel_2024,

title = {A Novel Framework for Hand Visualization in Web-Based Collaborative XR},

author = {L Schwenderling and W Herbrich and F Joeres and C Hansen},

url = {https://ieeexplore.ieee.org/document/10536317/},

doi = {10.1109/VRW62533.2024.00010},

isbn = {979-8-3503-7449-0},

year  = {2024},

date = {2024-03-01},

urldate = {2024-03-01},

booktitle = {2024 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {18–23},

publisher = {IEEE},

address = {Orlando, FL, USA},

abstract = {Many extended reality (XR) applications are platform-specific, making accessibility and cross-platform collaboration difficult. Web-based collaborative XR can enhance adoption of XR technologies, using the browser as a platform-independent interface. However, challenges arise from the browser environment, such as performance limitations. To this end, we present a WebXR-based framework for hand interaction in cross-platform collaboration in XR. A network structure and methods for collaborative and individual object manipulation complement the integrated hand tracking. Three different fidelity levels to represent the hands of remote users were implemented to accommodate different performance capabilities. Concepts ranged from virtual hands to discrete poses with abstract objects. A sample application was implemented with a puzzle task. Two users collaborated in the browsers of the Microsoft HoloLens 2 and the Meta Quest 2. Qualitative and quantitative data on user performance (n=9), and frame rate recordings (n=1) were collected. All users were able to solve the puzzle together quickly and intu-itively. The Quest environment was preferred, as there were more performance issues with the HoloLens. Hand interaction was well-received and proved to be sufficient as the only form of communication. Simpler representations of the hands lead to a higher frame rate, whereby the effects were device-dependent. The impact on task performance was low. Hand interaction enables an intuitive exchange of objects and basic communication in cross-platform collaboration via browsers. Depending on the XR environment, however, device-specific performance limitations must be taken into account by modulating the amount of data and rendering effort.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_ar-based_2024,

title = {An AR-Based Multi-User Learning Environment for Anatomy Seminars},

author = {D Schott and M Kunz and J Mandel and L Schwenderling and R Braun-Dullaeus and C Hansen},

url = {https://ieeexplore.ieee.org/document/10536568/},

doi = {10.1109/VRW62533.2024.00271},

isbn = {979-8-3503-7449-0},

year  = {2024},

date = {2024-03-01},

urldate = {2024-03-01},

booktitle = {2024 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {949–950},

publisher = {IEEE},

address = {Orlando, FL, USA},

abstract = {Understanding the intricate and rapid changes in shape during em-bryonic formation is vital for medical students. Using the example of embryonic human heart development, we introduce an AR-based multi-user approach to enhance understanding and foster a participatory learning environment. Through a user-centered approach, we created a prototype accommodating two player roles and enabling multi-modal inputs to encourage dynamic group discussions. We in-vited four anatomy experts to evaluate three system configurations in an interdisciplinary workshop to assess the feasibility of integration into anatomy seminars. The gathered data and feedback indicate the potential of our collaborative concept for integration into the medical curriculum.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bashkanov_automatic_2024,

title = {Automatic Patient-level Diagnosis of Prostate Disease with Fused 3D MRI and Tabular Clinical Data},

author = {O Bashkanov and M Rak and L Engelage and C Hansen},

url = {https://proceedings.mlr.press/v227/bashkanov24a.html},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

booktitle = {Medical Imaging with Deep Learning},

pages = {1225–1238},

publisher = {PMLR},

abstract = {Computer-aided diagnosis systems for automatic prostate cancer diagnosis can provide radiologists with decision support during image reading. However, in this case, patient-relevant information often remains unexploited due to the greater focus on the image recognition side, with various imaging devices and modalities, while omitting other potentially valuable clinical data. Therefore, our work investigates the performance of recent methods for the fusion of rich image data and heterogeneous tabular data. Those data may include patient demographics as well as laboratory data, e.g., prostate-specific antigen (PSA). Experiments on the large dataset (3800 subjects) indicated that when using the fusion method with demographic data in clinically significant prostate cancer (csPCa) detection tasks, the mean area under the receiver operating characteristic curve (ROC AUC) has improved significantly from 0.736 to 0.765. We also observed that the naïve concatenation performs similarly or even better than the textbackslashmboxstate-of-the-art fusion modules. We also achieved better prediction quality in grading prostate disease by including more samples from longitudinal PSA profiles in the tabular feature set. Thus, by including the three last PSA samples per patient, the best-performing model has reached AUC of 0.794 and a quadratic weighted kappa score (QWK) of 0.464, which constitutes a significant improvement compared with the image-only method, with ROC AUC of 0.736 and QWK of 0.342.},

note = {ISSN: 2640-3498},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{wagnerberger_empowering_2024,

title = {Empowering Patients: Improve Gender-Sensitive Medical Knowledge Through Interactive Edutainment},

author = {D Wagnerberger and D Schott and L Schwenderling and C Hansen and D Schumacher},

url = {https://dl.acm.org/doi/10.1145/3679318.3685500},

doi = {10.1145/3679318.3685500},

isbn = {979-8-4007-0966-1},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

booktitle = {Proceedings of the 13th Nordic Conference on Human-Computer Interaction},

pages = {1–12},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {NordiCHI '24},

abstract = {Disregarding crucial gender-specific differences and potential risks in medicine leads to widespread gender inequalities. This paper introduces interactive edutainment concepts developed through a user-centered design approach to raise awareness of gender medicine. An interactive exhibition course and an accompanying deck of cards provide an engaging and sensitizing experience of medical gender inequalities. Qualitative feedback, self-assessment, and user experience and behavior were evaluated during a public display of the concepts (n=14). The results highlight the potential of our playful approach to raising awareness among the public as well as health-related professionals, paving new ways for communication and empowerment of patients of all genders. We believe these insights have broader applicability across various domains, supporting efforts to address all forms of inequality.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{allgaier_gamification_2024,

title = {Gamification Concepts for a VR-based Visuospatial Training for Intraoperative Liver Ultrasound},

author = {M Allgaier and F Huettl and L Hanke and T Huber and B Preim and S Saalfeld and C Hansen},

url = {https://doi.org/10.1145/3613905.3650736},

doi = {10.1145/3613905.3650736},

isbn = {979-8-4007-0331-7},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

booktitle = {Extended Abstracts of the CHI Conference on Human Factors in Computing Systems},

pages = {1–8},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {CHI EA '24},

abstract = {Gamification is widely used due to its positive influence on learning by adding emotions and steering behavior. In medical VR training applications, the use of gamification is rare, and when it is implemented, it often lacks thoughtful design decisions and empirical evaluation. Using a VR-based training for intraoperative ultrasound for liver surgery, we analyzed game elements regarding their suitability and examined two in more detail: difficulty levels and a kit, where the user has to assemble a virtual liver using US. In a broad audience study, levels achieved significantly better results regarding enjoyment. Qualitative feedback from medical students directly comparing the elements revealed that they prefer the kit as well as levels for training. Our studies indicate that levels and the more interactive kit improve the learning experience, which could also be taken as a basis for similar VR-based medical training applications.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{polenz_simulating_2024,

title = {Simulating projective Augmented Reality Visualizations in Virtual Reality: Is VR a feasible Environment for medical AR Evaluations?},

author = {L Polenz and F Joeres and C Hansen and F Heinrich},

url = {https://doi.org/10.1145/3613905.3650843},

doi = {10.1145/3613905.3650843},

isbn = {979-8-4007-0331-7},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

booktitle = {Extended Abstracts of the CHI Conference on Human Factors in Computing Systems},

pages = {1–8},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {CHI EA '24},

abstract = {Augmented Reality (AR) has demonstrated potential in medical applications, such as enhancing surgical navigation. However, evaluating medical AR visualizations entails high costs and effort to provide suitable hardware solutions. This is particularly crucial in projective AR, as these systems require several error-prone calibration and registration steps. This work investigates the suitability of Virtual Reality (VR) as a cost-effective and controlled study environment for evaluating projective AR visualizations. A virtual twin of a real laboratory environment was created, and a user study comparing two needle navigation visualizations was conducted. The study simulated identical experiments in both AR and VR to assess if similar results would emerge. Our findings indicate that both AR and VR experiments exhibited comparable effects in terms of performance and workload of both needle insertion visualizations. This study serves as a preliminary step in demonstrating the feasibility of using VR as an evaluation environment for projective AR visualizations.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_stand_2024,

title = {Stand Alone or Stay Together: An In-situ Experiment of Mixed-Reality Applications in Embryonic Anatomy Education},

author = {D Schott and M Kunz and F Heinrich and J Mandel and A Albrecht and R Braun-Dullaeus and C Hansen},

url = {https://dl.acm.org/doi/10.1145/3641825.3687706},

doi = {10.1145/3641825.3687706},

isbn = {979-8-4007-0535-9},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

booktitle = {Proceedings of the 30th ACM Symposium on Virtual Reality Software and Technology},

pages = {1–11},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {VRST '24},

abstract = {Where traditional media and methods reach their limits in anatomy education, mixed-reality (MR) environments can provide effective learning support because of their high interactivity and spatial visualization capabilities. However, the underlying design and pedagogical requirements are as diverse as the technologies themselves. This paper examines the effectiveness of individual- and collaborative learning environments for anatomy education, using embryonic heart development as an example. Both applications deliver the same content using identical visualizations and hardware but differ in interactivity and pedagogical approach. The environments were evaluated in a user study with medical students (n = 90) during their examination phase, assessing usability, user experience, social interaction/co-presence, cognitive load, and personal preference. Additionally, we conducted a knowledge test before and after an MR learning session to determine educational effects compared to a conventional anatomy seminar. Results indicate that the individual learning environment was generally preferred. However, no significant difference in learning effectiveness could be shown between the conventional approach and the MR applications. This suggests that both can effectively complement traditional seminars despite their different natures. Our study contributes to understanding how different MR settings could be tailored for anatomical education.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_cardiocolab_2024,

title = {CardioCoLab: Collaborative Learning of Embryonic Heart Anatomy in Mixed Reality},

author = {D Schott and F Heinrich and M Kunz and J Mandel and A Albrecht and R Braun-Dullaeus and C Hansen},

url = {https://diglib.eg.org/handle/10.2312/vcbm20241191},

doi = {10.2312/VCBM.20241191},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

booktitle = {Eurographics Workshop on Visual Computing for Biology and Medicine},

abstract = {The complexity of embryonic heart development presents significant challenges for medical education, particularly in illustrating dynamic morphological changes over short time periods. Traditional teaching methods, such as 2D textbook illustrations and static models, are often insufficient for conveying these intricate processes. To address this gap, we developed a multi-user Mixed Reality (MR) system designed to enhance collaborative learning and interaction with virtual heart models. Building on previous research, we identified the needs of both students and teachers, implementing various interaction and visualization features iteratively. An evaluation with teachers and students (N = 12) demonstrated the system's effectiveness in improving engagement and understanding of embryonic heart development. The study highlights the potential of MR in medical seminar settings as a valuable addition to medical education by enhancing traditional learning methods.},

note = {Artwork Size: 5 pages 

Edition: 1191 

ISBN: 9783038682448 

Publisher: The Eurographics Association},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{mielke_interactive_2023,

title = {Interactive Registration Methods for Augmented Reality in Robotics: A Comparative Evaluation},

author = {T Mielke and F Joeres and D Schott and C Hansen},

url = {https://ieeexplore.ieee.org/document/10322246/},

doi = {10.1109/ISMAR-Adjunct60411.2023.00109},

isbn = {979-8-3503-2891-2},

year  = {2023},

date = {2023-10-01},

urldate = {2023-10-01},

booktitle = {2023 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct)},

pages = {501–506},

publisher = {IEEE},

address = {Sydney, Australia},

abstract = {Augmented Reality (AR) visualization has shown potential for supporting intuitive and efficient human-robot interaction in a range of tasks. Since all these tasks are spatially related to the robot, the precise positioning of the AR content is critical to the applicability. However, most research has primarily focused on developing visualizations rather than exploring methods for aligning AR content in the robotic workspace. This paper aims to bridge this gap by implementing and comparing different interactive registration methods, including two point-based and one manual approach. We comparatively evaluated these registration methods in a user study (n=21), measuring registration accuracy, duration, and subjective user feedback. Our results indicate that the point-based methods outperform the manual approach in terms of both accuracy and perceived workload. Furthermore, participants achieved significantly faster performance with a point-based approach using physically defined registration points compared to a point-based approach using markers attached to the robot.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_is_2023,

title = {Is this the vReal Life? Manipulating Visual Fidelity of Immersive Environments for Medical Task Simulation},

author = {D Schott and F Heinrich and L Stallmeister and J Moritz and B Hensen and C Hansen},

url = {https://ieeexplore.ieee.org/document/10316533/},

doi = {10.1109/ISMAR59233.2023.00134},

isbn = {979-8-3503-2838-7},

year  = {2023},

date = {2023-10-01},

urldate = {2023-10-01},

booktitle = {2023 IEEE International Symposium on Mixed and Augmented Reality (ISMAR)},

pages = {1171–1180},

publisher = {IEEE},

address = {Sydney, Australia},

abstract = {Recent developments and research advances contribute to an ever-increasing trend towards quality levels close to what we experience in reality. In this work, we investigate how different degrees of these quality characteristics affect user performance, qualia of user experience (UX), and sense of presence in an example medical task. To this end, a two-way within-subjects design user study was conducted, in which three different levels of visual fidelity were compared. In addition, two different interaction modalities were considered: (1) the use of conventional VR controllers and (2) natural hand interaction using 3D-printed, spatially-registered replicas of medical devices, to interact with their virtual representations. Consistent results indicate that higher degrees of visual fidelity evoke a higher sense of presence and UX. However, user performance was less affected. Moreover, no differences were detected between both interaction modalities for the examined task. Future work should investigate the discovered interaction effects between quality levels and interaction modalities in more detail and examine whether these results can be reproduced in tasks that require more precision. This work provides insights into the implications to consider when studying interactions in VR and paves the way for investigations into early phases of medical product development and workflow analysis.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{allgaier_livrsono_2023,

title = {LiVRSono - Virtual Reality Training with Haptics for Intraoperative Ultrasound},

author = {M Allgaier and F Huettl and L Hanke and H Lang and T Huber and B Preim and S Saalfeld and C Hansen},

url = {https://ieeexplore.ieee.org/document/10316488/},

doi = {10.1109/ISMAR59233.2023.00114},

isbn = {979-8-3503-2838-7},

year  = {2023},

date = {2023-10-01},

urldate = {2023-10-01},

booktitle = {2023 IEEE International Symposium on Mixed and Augmented Reality (ISMAR)},

pages = {980–989},

publisher = {IEEE},

address = {Sydney, Australia},

abstract = {One of the biggest challenges in using ultrasound (US) is learning to create a spatial mental model of the interior of the scanned object based on the US image and the probe position. As intraoperative ultrasound (IOUS) cannot be easily trained on patients, we present LiVRSono, an immersive VR application to train this skill. The immersive environment, including an US simulation with patientspecific data as well as haptics to support hand-eye coordination, provides a realistic setting. Four clinically relevant training scenarios were identified based on the described learning goal and the workflow of IOUS for liver. The realism of the setting and the training scenarios were evaluated with eleven physicians, of which six participants are experts in IOUS for liver and five participants are potential users of the training system. The setting, handling of the US probe, and US image were considered realistic enough for the learning goal. Regarding the haptic feedback, a limitation is the restricted workspace of the input device. Three of the four training scenarios were rated as meaningful and effective. A pilot study regarding learning outcome shows positive results, especially with respect to confidence and perceived competence. Besides the drawbacks of the input device, our training system provides a realistic learning environment with meaningful scenarios to train the creation of a mental 3D model when performing IOUS. We also identified important improvements to the training scenarios to further enhance the training experience.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_uuxr-framework_2023,

title = {The UUXR-Framework: A Draft Classification for Using Extended Reality in Usability and User Experience Research},

author = {D Schott and J Moritz and C Hansen and F Joeres},

url = {https://ieeexplore.ieee.org/document/10322234/},

doi = {10.1109/ISMAR-Adjunct60411.2023.00100},

isbn = {979-8-3503-2891-2},

year  = {2023},

date = {2023-10-01},

urldate = {2023-10-01},

booktitle = {2023 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct)},

pages = {460–465},

publisher = {IEEE},

address = {Sydney, Australia},

abstract = {Conducting human-centered evaluations in extended reality (XR) environments is a growing trend in user research and usability engineering. However, there has been little to no systematic investigation of the emerging methods in this field published to date. The motivation behind our work is to explore and classify strategies and methods for utilizing XR technologies in the context of usability and user experience (UUX) activities. This paper proposes a draft classification framework for the use of XR technologies in UUX activities, combining an informal exploration of relevant literature with established UUX methods. Within this framework, we propose 12 dimensions that we consider potentially relevant for determining whether and how the use of XR technologies can benefit product development and user research. To evaluate the structure and phrasing of our proposed dimensions, we conducted an initial evaluation with UUX professionals (N = 11). We believe that our dimensions form an early-stage foundation for future guidelines aimed at UUX researchers. The framework serves as a tool for assessing different levels of virtualization in UUX work and facilitating knowledge transfer between academia and industry.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{chheang_virtual_2023,

title = {Virtual Resection Planning using Bezier Surface Interactions in Collaborative VR Environments},

author = {V Chheang and R Bruggernann and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/10108900},

doi = {10.1109/VRW58643.2023.00041},

year  = {2023},

date = {2023-03-01},

urldate = {2023-03-01},

booktitle = {2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {166–169},

abstract = {The use of virtual reality (VR) has been proposed for collaborative planning or training scenarios to aid surgeons in preparing surgical interventions. In this paper, we explore the usage of cubic Bezier surfaces and their respective interactions in collaborative VR environments to define atypical resection surfaces for planning abdominal organ tumor resections. We conducted a pilot study (n = 10) to evaluate the usability of the Bezier surface interaction compared to a free deformation approach using the example of liver surgery planning. Moreover, we showed the prototype to an expert and conducted an interview to collect clinical feedback. The results show potential benefits of both interaction techniques that could be essential for virtual resection planning and training. The expert highlighted that combining both techniques could speed up the workflow and provide various options for planning.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gulamhussene_deep_2023,

title = {Deep Learning-based Marker-less Pose Estimation of Interventional Tools using Surrogate Keypoints},

author = {G Gulamhussene and J Spiegel and A Das and M Rak and C Hansen},

editor = {T Deserno and H Handels and A Maier and K Maier-Hein and C Palm and T Tolxdorff},

doi = {10.1007/978-3-658-41657-7_63},

isbn = {978-3-658-41657-7},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

booktitle = {Bildverarbeitung für die Medizin 2023},

pages = {292–298},

publisher = {Springer Fachmedien},

address = {Wiesbaden},

abstract = {Estimating the position of an intervention needle is an important ability in computer-assisted interventions. Currently, such pose estimations rely either on radiation-intensive CT imaging or need additional optical markers which add overhead to the clinical workflow. We propose a novel deep-learning-based technique for pose estimation of interventional tools which relies on detecting visible features on the tool itself without additional markers.We also propose a novel and fast pipeline for creating vast amounts of robustly labeled and markerless ground truth data for training such neural networks. Initial evaluations suggest that with needle base and needle tip localization errors of about 1 and 4 cm, Our approach can yield a search corridor that can be used to find the needle in a low-dose CT image, reducing radiation exposure.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gulamhussene_needle_2023,

title = {Needle Tip Tracking During CT-guided Interventions using Fuzzy Segmentation},

author = {G Gulamhussene and A Das and J Spiegel and D Punzet and M Rak and C Hansen},

editor = {T Deserno and H Handels and A Maier and K Maier-Hein and C Palm and T Tolxdorff},

doi = {10.1007/978-3-658-41657-7_62},

isbn = {978-3-658-41657-7},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

booktitle = {Bildverarbeitung für die Medizin 2023},

pages = {285–291},

publisher = {Springer Fachmedien},

address = {Wiesbaden},

abstract = {CT-guided interventions are standard practice for radiologists to treat lesions in various parts of the human body. In this context, accurate tracking of instruments is of paramount importance for the safety of the procedure and helps radiologists avoid unintended damage to adjacent organs. In this work, a novel method for the estimation of 3D needle tip coordinates in a CT volume using only two 2D projections in an interventional setting is proposed. The method applies a deep learning model for the fuzzy segmentation of the region containing the tip on 2D projections and automatically extracts the position of the tip. A simple UNet achieves a Dice score of 0.9906 for the fuzzy segmentation and an average euclidean distance of 2.96 mm for the needle tip regression task.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gulamhussene_using_2023,

title = {Using Training Samples as Transitive Information Bridges in Predicted 4D MRI},

author = {G Gulamhussene and O Bashkanov and J Omari and M Pech and C Hansen and M Rak},

editor = {Z Xue and S Antani and G Zamzmi and F Yang and S Rajaraman and S Huang and M Linguraru and Z Liang},

doi = {10.1007/978-3-031-44917-8_23},

isbn = {978-3-031-44917-8},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

booktitle = {Medical Image Learning with Limited and Noisy Data},

pages = {237–245},

publisher = {Springer Nature Switzerland},

address = {Cham},

abstract = {The lack of real-time techniques for monitoring respiratory motion impairs the development of guidance systems for image-guided interventions. Recent works show that U-Net based real-time 4D MRI prediction methods are promising, but prone to bad image quality when small training data sets and inputs with multiple MR contrast are used. To overcome this problem, we propose a more efficient use of the spare training data and re-utilize 2D training samples as a secondary input for construction of transitive information bridges between the navigator slice primary input and the data slice prediction. We thus remove the need for a separate 3D breath-hold MRI with different MR contrast as the secondary input. Results show that our novel construction leads to improved prediction quality with very sparse training data, with a significant decrease in root mean squared error (RMSE) from 0.3 to 0.27 (p$$<2.2eˆ-16$$<2.2e-16},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bublak_virtual_2022,

title = {A Virtual Environment for Emergency Ultrasound Training during Cardiopulmonary Resuscitation},

author = {T Bublak and M Bofferding and C Olson and H Jonas and J Rademeier and C Hansen},

url = {https://doi.org/10.1145/3543758.3547516},

doi = {10.1145/3543758.3547516},

isbn = {978-1-4503-9690-5},

year  = {2022},

date = {2022-09-01},

urldate = {2022-09-01},

booktitle = {Proceedings of Mensch und Computer 2022},

pages = {608–610},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {MuC '22},

abstract = {We propose a virtual reality (VR) communication training environment to train cardiopulmonary resuscitation (CPR) and ultrasound (US) imaging simultaneously. Existing simulators only allow separate training of the two procedures. Our method separates the users spatially, as they each work on their own manikin. One manikin is part of a US simulator commonly used in medical training, and the other manikin is a CPR manikin. Our VR application simulates the users working on the same virtual patient. This allows for an immersive training experience in which communication skills, which are especially important in such critical situations, can be practiced by medical professionals. The prototype has the potential to provide an important foundation for advanced VR-based emergency medical training.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{heinrich_2d_2022,

title = {2D versus 3D: A Comparison of Needle Navigation Concepts between Augmented Reality Display Devices},

author = {F Heinrich and L Schwenderling and F Joeres and C Hansen},

url = {https://ieeexplore.ieee.org/document/9756753},

doi = {10.1109/VR51125.2022.00045},

year  = {2022},

date = {2022-03-01},

urldate = {2022-03-01},

booktitle = {2022 IEEE Conference on Virtual Reality and 3D User Interfaces (VR)},

pages = {260–269},

abstract = {Surgical procedures requiring needle navigation assistance suffer from complicated hand-eye coordination and are mentally demanding. Augmented reality (AR) can help overcome these issues. How-ever, only an insufficient amount of fundamental research has focused on the design and hardware selection of such AR needle navigation systems. This work contributes to this research area by presenting a user study (n=24) comparing three state-of-the-art navigation concepts displayed by an optical see-through head-mounted display and a stereoscopic projection system. A two-dimensional glyph visualization resulted in higher targeting accuracy but required more needle insertion time. In contrast, punctures guided by a three-dimensional see-through vision concept were less accurate but faster and were favored in a qualitative interview. The third concept, a static representation of the correctly positioned needle, showed too high target errors for clinical accuracy needs. This concept per-formed worse when displayed by the projection system. Besides that, no meaningful differences between the evaluated AR display devices were detected. User preferences and use case restrictions, e.g., sterility requirements, seem to be more crucial selection criteria. Future work should focus on improving the accuracy of the see-through vision concept. Until then, the glyph visualization is recommended.},

note = {ISSN: 2642-5254},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{hombeck_evaluating_2022,

title = {Evaluating Perceptional Tasks for Medicine: A Comparative User Study Between a Virtual Reality and a Desktop Application},

author = {J Hombeck and M Meuschke and L Zyla and A Heuser and J Toader and F Popp and C Bruns and C Hansen and R Datta and K Lawonn},

url = {https://ieeexplore.ieee.org/abstract/document/9756759},

doi = {10.1109/VR51125.2022.00071},

year  = {2022},

date = {2022-03-01},

urldate = {2022-03-01},

booktitle = {2022 IEEE Conference on Virtual Reality and 3D User Interfaces (VR)},

pages = {514–523},

abstract = {Since for most consumers the Virtual Reality (VR) experience exceeds that of desktop applications, an increasing number of applications is being transferred from desktop to VR. Industrial and entertainment applications primarily expect for a richer consumer experience, while others, such as surgical applications, seek for improved precision over their desktop counterparts. One way to improve the performance of precision-based VR applications is to provide suitable visualizations. Today, these "suitable" visualizations are mostly transferred from desktop to VR without considering their spatial and temporal performance might change in VR. This may not lead to an optimal solution, which can be crucial for precision-based tasks. Misinterpretation of shape or distance in a surgical or pre-operative simulation can affect the chosen treatment and thus directly impact the outcome. Therefore, we evaluate the performance differences of multiple visualizations for 3D surfaces based on their shape and distance estimation for desktop and VR applications. We conducted a quantitative user study with 56 participants evaluating seven visualizations (Phong, Toon, Fresnel, Pseudo-Chromadepth, Heatmap, Isolines, and Arrow Glyphs). Our results show that the performance of each visualization varies depending on the task, system, and surface type, with VR generally providing improved results. While Isolines are able to improve distance estimation, Phong and Heatmaps are beneficial for shape estimation.},

note = {ISSN: 2642-5254},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{chheang_group_2022,

title = {Group WiM: A Group Navigation Technique for Collaborative Virtual Reality Environments},

author = {V Chheang and F Heinrich and F Joeres and P Saalfeld and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/9757426},

doi = {10.1109/VRW55335.2022.00129},

year  = {2022},

date = {2022-03-01},

urldate = {2022-03-01},

booktitle = {2022 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {556–557},

abstract = {In this work, we present a group World-in-Miniature (WiM) navigation technique that allows a guide to navigate a team in collaborative virtual reality (VR) environments. We evaluated the usability, discomfort, and user performance of the proposed technique compared to state-of-the-art group teleportation in a user study łeft(ntextbackslash,=textbackslash,21textbackslashright). The results show that the proposed technique induces less discomfort for the guide and has slight usability advantages. Additionally, the group WiM technique seems superior in regards to task completion time for obstructed target destination. However, it performs similarly to the group teleportation technique in direct line of sight cases. The group WiM technique provides potential benefits for effective group navigation in complex virtual environments and harder-to-reach target locations.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{chheang_towards_2022,

title = {Towards Virtual Teaching Hospitals for Advanced Surgical Training},

author = {V Chheang and D Schott and P Saalfeld and L Vradelis and T Huber and F Huettl and H Lang and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/9757460},

doi = {10.1109/VRW55335.2022.00089},

year  = {2022},

date = {2022-03-01},

urldate = {2022-03-01},

booktitle = {2022 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {410–414},

abstract = {Existing virtual training environments in medicine usually focus only on the training of a specific medical skill and are conducted in a single virtual room. However, medical challenges are often in the context of the planning procedure and operating room intervention. Therefore, it is crucial to provide a training environment that tackles these issues. In this paper, we present a prototype of surgical department within a virtual teaching hospital. It supports multiple users, photo-realistic avatars, and training scenarios ranging from planning procedures to laparoscopic surgery in the virtual operating room. Medical data for each virtual patient is synchronized across the different rooms, allowing users to view, analyze and train on key decision points from diagnosis to surgical incision for each patient. The environment was evaluated in a pilot study with five surgical residents and one medical student. The experts assessed the environment as an essential tool to evaluate and improve surgical planning as well as the training during critical situations of the surgical procedures. We conclude that the development of the virtual teaching hospital components described here has the potential to be a basis for future generations of medical training simulators.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{batz_accessible_2022,

title = {Accessible Design of Serious Games for People with Intellectual Disabilities in Inclusive Vocational Education},

author = {V Batz and I Lipowski and M Morfeld and C Hansen and M Herzog},

url = {https://dl.digra.org/index.php/dl/article/view/1372},

doi = {10.26503/dl.v2022i1.1372},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

booktitle = {Proceedings of DiGRA 2022 Conference: Bringing Worlds Together},

abstract = {People with disabilities are often denied the opportunity to obtain a vocational qualification. There is a lack of an appropriate infrastructure for an inclusive education system and recognized degrees. Therefore, didactic methods for inclusive learning situations are needed. This paper describes the user-centered development and evaluation of a serious game for inclusive vocational training in kitchen professions. The theoretical teaching content in the module “hygiene” is taught to people with and without cognitive impairments using a gamified learning application. The prototype was evaluated with 22 participants when used in an inclusive teaching setting with a mixed-methods design. The learning application caused an increase in motivation and the knowledge quiz achieved good results across all target groups (15 trainee cooks, 4 trainees as kitchen assistants, 3 employees of the sheltered workshop). The results from questioning, learning quiz, observation, and video analysis form design guidelines for future digital, interactive teaching methods for inclusive vocational education.},

note = {ISSN: 2342-9666},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{hombeck_distance_2022,

title = {Distance Visualizations for Vascular Structures},

author = {J Hombeck and M Meuschke and S Lieb and N Lichtenberg and R Datta and M Krone and C Hansen and B Preim and K Lawonn},

doi = {10.2312/vcbm.20221182},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

booktitle = {Eurographics Workshop on Visual Computing for Biology and Medicine},

pages = {1-10},

abstract = {The role of expressive surface visualizations in rendering vascular structures has seen an increased impact over the last years. Surface visualizations provide an overview of complex anatomical structures and support treatment planning as well as medical education. To support decision-making, physicians need visualizations that depict anatomical structures and their spatial relations to each other, i.e., well perceivable visual encodings of egocentric and endocentric distances.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{mielke_natural_2022,

title = {Natural 3D Object Manipulation for Interactive Laparoscopic Augmented Reality Registration},

author = {T Mielke and F Joeres and C Hansen},

editor = {JYC Chen and G Fragomeni},

doi = {10.1007/978-3-031-05939-1_21},

isbn = {978-3-031-05939-1},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

booktitle = {Virtual, Augmented and Mixed Reality: Design and Development},

pages = {317–328},

publisher = {Springer International Publishing},

address = {Cham},

abstract = {Due to the growing focus on minimally invasive surgery, there is increasing interest in intraoperative software support. For example, augmented reality can be used to provide additional information. Accurate registration is required for effective support. In this work, we present a manual registration method that aims at mimicking natural manipulation of 3D objects using tracked surgical instruments. This method is compared to a point-based registration method in a simulated laparoscopic environment. Both registration methods serve as an initial alignment step prior to surface-based registration refinement. For the evaluation, we conducted a user study with 12 participants. The registration methods were compared in terms of registration accuracy, registration duration, and subjective usability feedback. No significant differences could be found with respect to the previously mentioned criteria between the manual and the point-based registration methods. Thus, the manual registration did not outperform the reference method. However, we found that our method offers qualitative advantages, which may make it more suitable for some application scenarios. Furthermore we identified possible approaches for improvement, which should be investigated in the future to strengthen possible advantages of our registration method.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gabele_effects_2022,

title = {Effects and Combination of Tailored Browser-Based and Mobile Cognitive Software Training},

author = {M Gabele and A Thoms and S Schröer and S Hußlein and C Hansen},

editor = {BÞ Jónsson and C Gurrin and M Tran and D Dang-Nguyen and A Hu and BHT Thanh and B Huet},

doi = {10.1007/978-3-030-98355-0_24},

isbn = {978-3-030-98355-0},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

booktitle = {MultiMedia Modeling},

pages = {279–291},

publisher = {Springer International Publishing},

address = {Cham},

abstract = {Software-based training supports maintenance or recovery of cognitive abilities. However, regular use needs a high self-motivation. For this, the individual needs of users should be taken into account during the development process. Thus, in this work, two possibilities for tailoring in combination of application, and media devices in practice are investigated in an explorative between-subject design and hypothesis-generating study (N = 68). First, the effect of a browser-based training without gamification or with assignment of gamification appropriate to mean user characteristic on training duration is investigated. Second, the effect of this training and a subsequent serious game app on perception and possible combinations of different media is investigated. The results of behavior lead to the hypothesis that with tailored gamification in browsers, users may train longer in the middle range of training duration. The results of perception show a significant difference and higher perceived value/usefulness and overall rating, as well as the assumption of a higher effect in computer and mobile training in the group with tailored gamification. This could therefore provide a basis for combinations. A combination of both usage scenarios is perceived by users as most reasonable for a positive training effect. Nevertheless, there is a high variance for self-assessed usage. Thus, the results support developing multiple combinable scenarios, tailored to the user, in media devices and game integration to address intended effects, development and user needs to support the effect of cognitive software training in practice.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{heinrich_effects_2021,

title = {Effects of Surface Visualizations on Depth Perception in Projective Augmented Reality},

author = {F Heinrich and L Schwenderling and M Streuber and K Bornemann and K Lawonn and C Hansen},

url = {https://ieeexplore.ieee.org/document/9582452},

doi = {10.1109/ICHMS53169.2021.9582452},

year  = {2021},

date = {2021-09-01},

urldate = {2021-09-01},

booktitle = {2021 IEEE 2nd International Conference on Human-Machine Systems (ICHMS)},

pages = {1–6},

abstract = {Depth perception is a common issue in augmented reality (AR). Projective AR, where the spatial relations between the projection surface and displayed virtual contents need to be represented properly, is particularly affected. This is crucial in the medical domain, e.g., for the distances between the patient’s skin and projected inner anatomical structures, but not much research was conducted in this context before. To this end, this work investigates the applicability of surface visualization techniques to support the perception of spatial relations in projective AR. Four methods previously explored in different domains were combined with the projection of inner anatomical structures on a human torso phantom. They were evaluated in a comparative user study (n=21) with respect to a distance estimation and a sorting task. Measures included Task completion time, accuracy, total Head movement and Confidence of the participants. Consistent results across variables show advantages of more occluding surface visualizations for the distance estimation task. Opposite results were obtained for the sorting task. This suggests that the amount of needed surface preservation depends on the use case and individual occlusion compromises need to be explored in future work.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{ernst_trajectory_2021,

title = {Trajectory Upsampling for Sparse Conebeam Projections Using Convolutional Neural Networks},

author = {P Ernst and M Rak and C Hansen and G Rose and A Nürnberger},

editor = {G Schramm and A Rezaei and K Thielemans and J Nuyts},

url = {https://arxiv.org/abs/2110.04143},

year  = {2021},

date = {2021-07-19},

urldate = {2021-07-19},

booktitle = {Proceedings of the 16th Virtual International Meeting on Fully 3D Image Reconstruction in Radiology and Nuclear Medicine},

pages = {285–288},

abstract = {In this paper, we present an approach based on a combination of convolutional neural networks and analytical algorithms to interpolate between neighboring conebeam projections for upsampling along circular trajectories. More precisely, networks are trained to interpolate the angularly centered projection between the input projections of different angular distances. Experiments show that an analytical interpolation as additional input is more beneficial than adding more neighboring projections. Using our best model, we achieve an x8 upsampling by repeating the interpolation three times. Though not depending on a specific reconstruction algorithm, we show that FDK reconstructions substantially benefit from this upsampling for removing streak artifacts. Using this FDK reconstruction as initialization for ART is also superior to other initializations but comes with a higher computation time and therefore cannot be considered as an option in an interventional setting.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gabele_effects_2021,

title = {Effects and Ways of Tailored Gamification in Software-Based Training in Cognitive Rehabilitation},

author = {M Gabele and J Weicker and S Wagner and A Thoms and S Hußlein and C Hansen},

url = {https://dl.acm.org/doi/10.1145/3450613.3456828},

doi = {10.1145/3450613.3456828},

isbn = {978-1-4503-8366-0},

year  = {2021},

date = {2021-06-01},

urldate = {2021-06-01},

booktitle = {Proceedings of the 29th ACM Conference on User Modeling, Adaptation and Personalization},

pages = {158–168},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {UMAP '21},

abstract = {A high level of motivation and frequent training are relevant in software-based rehabilitation to improve cognitive functioning after acquired brain injury. We evaluated the benefit of tailored user-centered gamification elements in a clinical study with N=83 outpatients undergoing three weeks of cognitive training in their home environment. The use of gamification in relation to the patient’s player type was explored in three steps. First, we determined the individual player types and related requests for specific game elements by means of questionnaires. Afterwards, we examined the effect of gamified training based on a non-player character and training progress within a metaphor. We considered secondly the individual perception and emotional effect and thirdly the performance based on training duration. 37 elements were requested by patients of all types, 18 elements were partially requested, and 4 elements were rejected. A comparison shows that the requested game elements partly differ between healthy persons and patients. Overall, gamification was perceived positively and gamified training leads to an increase in enjoyment compared to non-gamified training. In detail, however, there were different effects on the individual player types: socialisers experienced more enjoyment while achievers perceived higher competence throughout gamified cognitive training. Also, differences in performance in training duration were found. Within gamified training, socialisers trained significantly more than patients not primarily assigned to this type. In contrast, no significant difference was found for achievers. By showing modulating requests and effects in player types, our results support user-centered tailoring of game elements in the development of software-based cognitive training in rehabilitation.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{joeres_audiovisual_2021,

title = {Audiovisual AR Concepts for Laparoscopic Subsurface Structure Navigation},

author = {F Joeres and D Black and S Razavizadeh and C Hansen},

url = {https://graphicsinterface.org/proceedings/gi2021/gi2021-34/},

doi = {10.20380/GI2021.34},

year  = {2021},

date = {2021-05-28},

urldate = {2021-01-01},

booktitle = {Proceedings of Graphics Interface 2021},

pages = {224–230},

publisher = {Canadian Human-Computer Communications Society},

abstract = {The identification of subsurface structures during resection wound repair is a challenge during minimally invasive partial nephrectomy. Specifically, major blood vessels and branches of the urinary collecting system need to be localized under time pressure as target or risk structures during suture placement. This work presents concepts for AR visualization and auditory guidance based on tool position that support this task. We evaluated the concepts in a laboratory user study with a simplified, simulated task: The localization of subsurface target points in a healthy kidney phantom. We evaluated the task time, localization accuracy, and perceived workload for our concepts and a control condition without navigation support. The AR visualization improved the accuracy and perceived workload over the control condition. We observed similar, non-significant trends for the auditory display. Further, clinically realistic evaluation is pending. Our initial results indicate the potential benefits of our concepts in supporting laparoscopic resection wound repair.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bashkanov_learning_2021,

title = {Learning Multi-Modal Volumetric Prostate Registration With Weak Inter-Subject Spatial Correspondence},

author = {O Bashkanov and A Meyer and D Schindele and M Schostak and K Tönnies and C Hansen and M Rak},

url = {https://ieeexplore.ieee.org/abstract/document/9433848},

doi = {10.1109/ISBI48211.2021.9433848},

year  = {2021},

date = {2021-04-01},

urldate = {2021-04-01},

booktitle = {2021 IEEE 18th International Symposium on Biomedical Imaging (ISBI)},

pages = {1817–1821},

abstract = {Recent studies demonstrated the eligibility of convolutional neural networks (CNNs) for solving the image registration problem. CNNs enable faster transformation estimation and greater generalization capability needed for better support during medical interventions. Conventional fully-supervised training requires a lot of high-quality ground truth data such as voxel-to-voxel transformations, which typically are attained in a too tedious and error-prone manner. In our work, we use weakly-supervised learning, which optimizes the model indirectly only via segmentation masks that are a more accessible ground truth than the deformation fields. Concerning the weak supervision, we investigate two segmentation similarity measures: multiscale Dice similarity coefficient (mDSC) and the similarity between segmentation-derived signed distance maps (SDMs). We show that the combination of mDSC and SDM similarity measures results in a more accurate and natural transformation pattern together with a stronger gradient coverage. Furthermore, we introduce an auxiliary input to the neural network for the prior information about the prostate location in the MR sequence, which mostly is available preoperatively. This approach significantly outperforms the standard two-input models. With weakly labelled MR-TRUS prostate data, we showed registration quality comparable to the state-of-the-art deep learning-based method.},

note = {ISSN: 1945-8452},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_vrar_2021,

title = {A VR/AR Environment for Multi-User Liver Anatomy Education},

author = {D Schott and P Saalfeld and G Schmidt and F Joeres and C Boedecker and F Huettl and H Lang and T Huber and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/9417662/},

doi = {10.1109/VR50410.2021.00052},

isbn = {978-1-6654-1838-6},

year  = {2021},

date = {2021-03-01},

urldate = {2021-03-01},

booktitle = {2021 IEEE Virtual Reality and 3D User Interfaces (VR)},

pages = {296–305},

publisher = {IEEE},

address = {Lisboa, Portugal},

abstract = {We present a Virtual and Augmented Reality multi-user prototype of a learning environment for liver anatomy education. Our system supports various training scenarios ranging from small learning groups to classroom-size education, where students and teachers can participate in virtual reality, augmented reality, or via desktop PCs. In an iterative development process with surgeons and teachers, a virtual organ library was created. Nineteen liver data sets were used comprising 3D surface models, 2D image data, pathology information, diagnosis and treatment decisions. These data sets can interactively be sorted and investigated individually regarding their volumetric and meta information. The three participation modes were evaluated within a user study with surgery lecturers (5) and medical students (5). We assessed the usability and presence using questionnaires. Additionally, we collected qualitative data with semistructured interviews. A total of 435 individual statements were recorded and summarized to 49 statements. The results show that our prototype is usable, induces presence, and potentially support the teaching of liver anatomy and surgery in the future.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{chheang_collaborative_2021-1,

title = {Collaborative VR for Liver Surgery Planning using Wearable Data Gloves: An Interactive Demonstration},

author = {V Chheang and V Apilla and P Saalfeld and C Boedecker and T Huber and F Huettl and H Lang and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/abstract/document/9419102},

doi = {10.1109/VRW52623.2021.00268},

year  = {2021},

date = {2021-03-01},

urldate = {2021-03-01},

booktitle = {2021 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)},

pages = {768–768},

abstract = {Preoperative planning for liver surgery is a critical procedure to assess a potential resection and it supports surgeons to define the affected vessels and resection volume. Traditional surgical planning systems are widely used to support the planning with the usage of desktop-based 3D and 2D visualizations. However, desktop-based systems offer limited interactions and visualizations compared to virtual reality (VR) [3]. A suitable technique to support collaboration among surgeons is required. Our previous works [1], [2] illustrate that using collaborative VR is essential to enhance communication, teamwork, and over-distance collaboration. In this work, we present a collaborative VR prototype to support liver surgery planning with intuitive interactions using wearable data gloves and VR controllers. The users can explore the patient data in both 2D and 3D representations. Thereafter, a virtual resection is specified by drawing lines on the 3D model representation. The virtual re-section is further refined to keep safety margins from the tumors. Moreover, real-time risk maps are visualized to support the surgeons during the modification. Finally, the results of the virtual resection are visualized as resection volumes with their indicated amount and colors. Future work aims to conduct an extensive clinical study to compare the suitability of these input devices.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schreiter_application_2021,

title = {Application Potential of Robot-Guided Ultrasound During CT-Guided Interventions},

author = {J Schreiter and F Joeres and C March and M Pech and C Hansen},

editor = {J Noble and S Aylward and A Grimwood and Z Min and S Lee and Y Hu},

doi = {10.1007/978-3-030-87583-1_12},

isbn = {978-3-030-87583-1},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

booktitle = {Simplifying Medical Ultrasound},

pages = {116–125},

publisher = {Springer International Publishing},

address = {Cham},

abstract = {CT-guided interventions are common practices in interventional radiology to treat oncological conditions. During these interventions, radiologists are exposed to radiation and faced with a non-ergonomic working environment. A robot-guided ultrasound (US) as a complementing imaging method for the purpose of needle guidance could help to overcome these challenges. A survey with 21 radiologists was made to analyze the application potential of US during CT-guided interventions with regard to anatomical regions to be scanned as locations of target lesions as well as specific situations during which US could complement CT imaging. The results indicate that the majority of respondents already applied US during CT-guided interventions for reasons of real-time imaging of the target lesion, organ, and needle movement as well as for lesions that are difficult to visualize in CT. Potential situations of US application were identified as out-of-plane needle insertion and puncturing lesions within the liver and subcutaneous lymph nodes. Interaction with a robot-guided US should be intuitive and include an improved sterility concept.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{gabele_potentials_2021,

title = {Potentials of a Web-Based Gamification Guidance for Knowledge Transfer Between Research and Industry},

author = {M Gabele and V Fischer and M Steinbrügge and D Thiemke and S Husslein and C Hansen},

url = {https://doi.org/10.1145/3450337.3483458},

doi = {10.1145/3450337.3483458},

isbn = {978-1-4503-8356-1},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

booktitle = {Extended Abstracts of the 2021 Annual Symposium on Computer-Human Interaction in Play},

pages = {301–307},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {CHI PLAY '21},

abstract = {Research results show that gamification can influence emotions, motivation and behavior. However, in order to apply the results in the software development in industry, they need to be easily accessible. To enable a knowledge transfer, a concept and a prototype for an interactive web-based tool were designed to summarize and visualize existing research results and practical examples in a simplified way regarding the use of gamification elements. Step by step, the user defines parameters such as context of use, age, gender and user type for the target group. Based on this, effects in research results are presented simplified and sorted in four categories in pie charts. This is intended to provide users in the industry with the competence to select appropriate gamification elements for their usage. The approach was developed in a user-centered way, including pre-study interviews with seven participants from research and / or industry, and then evaluated using a clickable prototype and qualitative open interviews. Potentials for industry and research were examined. The approach was perceived as supportive in selecting appropriate gamification elements for use in industry. It may lead to faster finding of research results, promote networking and may generate a kind of meta review. The elaboration of such tools may support the interconnection between research and industry, as well as the transfer and applicability of knowledge in gamification.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{bornemann_exploration_2020,

title = {Exploration of Medical Volume Data in Projective Augmented Reality: An Interactive Demonstration},

author = {K Bornemann and F Heinrich and K Lawonn and C Hansen},

url = {https://doi.org/10.1145/3404983.3410415},

doi = {10.1145/3404983.3410415},

isbn = {978-1-4503-7540-5},

year  = {2020},

date = {2020-09-01},

urldate = {2020-09-01},

booktitle = {Proceedings of Mensch und Computer 2020},

pages = {507–509},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {MuC '20},

abstract = {This article describes the implementation and usage of a prototype to explore medical volume data in projective augmented reality (AR). To allow real-time rendering of the data, a volume ray casting algorithm is implemented on the GPU. Furthermore, the volume data is distorted to be superimposed correctly from the user's perspective. To allow exploration of the dataset, the user can use an HTC Vive Controller to show or hide structures with either clipping or windowing. In the future, the proposed prototype might be used for diagnosis, planning and computer assisted surgery. First tests indicate that this setup increases spatial understanding of the volume data compared to conventional computer monitors.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{schott_lean-interaction_2020,

title = {Lean-Interaction: Passive Image Manipulation in Concurrent Multitasking},

author = {D Schott and B Hatscher and F Joeres and M Gabele and S Hußlein and C Hansen},

url = {https://graphicsinterface.org/proceedings/gi2020/gi2020-40/},

doi = {10.20380/GI2020.40},

year  = {2020},

date = {2020-05-28},

urldate = {2020-01-01},

booktitle = {Proceedings of Graphics Interface 2020},

pages = {404–412},

publisher = {Canadian Human-Computer Communications Society},

abstract = {Complex bi-manual tasks often benefit from supporting visual information and guidance. Controlling the system that provides this information is a secondary task that forces the user to perform concurrent multitasking, which in turn may affect the main task performance. Interactions based on natural behavior are a promising solution to this challenge. We investigated the performance of these interactions in a hands-free image manipulation task during a primary manual task with an upright stance. Essential tasks were extracted from the example of clinical workflow and turned into an abstract simulation to gain general insights into how different interaction techniques impact the user’s performance and workload. The interaction techniques we compared were full-body movements, facial expression, gesture and speech input. We found that leaning as an interaction technique facilitates significantly faster image manipulation at lower subjective workloads than facial expression. Our results pave the way towards efficient, natural, hands-free interaction in a challenging multitasking environment.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{wei_towards_2020,

title = {Towards Fully Automatic 2D US to 3D CT/MR Registration: A Novel Segmentation-Based Strategy},

author = {W Wei and M Rak and J Alpers and C Hansen},

url = {https://doi.org/10.1109/ISBI45749.2020.9098379},

doi = {10.1109/ISBI45749.2020.9098379},

isbn = {978-1-5386-9330-8},

year  = {2020},

date = {2020-04-01},

urldate = {2020-04-01},

booktitle = {2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI)},

pages = {433–437},

publisher = {IEEE},

address = {Iowa City, IA, USA},

abstract = {2D-US to 3D-CT/MR registration is a crucial module during minimally invasive ultrasound-guided liver tumor ablations. Many modern registration methods still require manual or semi-automatic slice pose initialization due to insufficient robustness of automatic methods. The state-of-the-art regression networks do not work well for liver 2D US to 3D CT/MR registration because of the tremendous inter-patient variability of the liver anatomy. To address this unsolved problem, we propose a deep learning network pipeline which instead of a regression starts with a classification network to recognize the coarse ultrasound transducer pose followed by a segmentation network to detect the target plane of the US image in the CT/MR volume. The rigid registration result is derived using plane regression. In contrast to the state-of-the-art regression networks, we do not estimate registration parameters from multi-modal images directly, but rather focus on segmenting the target slice plane in the volume. The experiments reveal that this novel registration strategy can identify the initial slice phase in a 3D volume more reliably than the standard regression-based techniques. The proposed method was evaluated with 1035 US images from 52 patients. We achieved angle and distance errors of 12.7 ± 6.2 degrees and 4.9 ± 3.1 mm, clearly outperforming the state-of-the-art regression strategy which results in 37.0 ± 15.6 degrees angle error and 19.0 ± 11.6 mm distance error.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{chheang_interactive_2019,

title = {An Interactive Demonstration of Collaborative VR for Laparoscopic Liver Surgery Training},

author = {V Chheang and P Saalfeld and T Huber and F Huettl and W Kneist and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/8942344/},

doi = {10.1109/AIVR46125.2019.00055},

isbn = {978-1-7281-5604-0},

year  = {2019},

date = {2019-12-01},

urldate = {2019-12-01},

booktitle = {2019 IEEE International Conference on Artificial Intelligence and Virtual Reality (AIVR)},

pages = {247–2471},

publisher = {IEEE},

address = {San Diego, CA, USA},

abstract = {We introduce a collaborative virtual reality (VR) system for planning and simulation in laparoscopic liver surgery training. Patient image data is used for surgical model visualization and simulation. We developed two modes for training in laparoscopic procedures: exploration and surgery mode. Surgical joysticks are used in surgery mode to provide training for psychomotor skills and cooperation between a camera assistant and an experienced surgeon. Continuous feedback from our clinical partner comprised an important part of the development. Our evaluation showed that surgeons were positive about the usability and usefulness of the developed system. For further details, please refer to our full article [1] and additional materials.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{chheang_collaborative_2019,

title = {Collaborative Virtual Reality for Laparoscopic Liver Surgery Training},

author = {V Chheang and P Saalfeld and T Huber and F Huettl and W Kneist and B Preim and C Hansen},

url = {https://ieeexplore.ieee.org/document/8942324/},

doi = {10.1109/AIVR46125.2019.00011},

isbn = {978-1-7281-5604-0},

year  = {2019},

date = {2019-12-01},

urldate = {2019-12-01},

booktitle = {2019 IEEE International Conference on Artificial Intelligence and Virtual Reality (AIVR)},

pages = {1–17},

publisher = {IEEE},

address = {San Diego, CA, USA},

abstract = {Virtual reality (VR) has been used in many medical training systems for surgical procedures. However, the current systems are limited due to inadequate interactions, restricted possibilities of patient data visualization, and collaboration. We propose a collaborative VR system for laparoscopic liver surgical planning and simulation. Medical image data is used for model visualization and manipulation. Additionally, laparoscopic surgical joysticks are used to provide an opportunity for a camera assistant to cooperate with an experienced surgeon in VR. Continuous clinical feedback led us to optimize the visualization, synchronization, and interactions of the system. Laparoscopic surgeons were positive about the systems’ usefulness, usability, and system performance. Additionally, limitations and potential for further development are discussed.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{heinrich_augmented_2019,

title = {Augmented Reality Visualisation Concepts to Support Intraoperative Distance Estimation},

author = {F Heinrich and G Schmidt and F Jungmann and C Hansen},

url = {https://doi.org/10.1145/3359996.3364818},

doi = {10.1145/3359996.3364818},

isbn = {978-1-4503-7001-1},

year  = {2019},

date = {2019-11-01},

urldate = {2019-11-01},

booktitle = {Proceedings of the 25th ACM Symposium on Virtual Reality Software and Technology},

pages = {1–2},

publisher = {Association for Computing Machinery},

address = {New York, NY, USA},

series = {VRST '19},

abstract = {The estimation of distances and spatial relations between surgical instruments and surrounding anatomical structures is a challenging task for clinicians in image-guided surgery. Using augmented reality (AR), navigation aids can be displayed directly at the intervention site to support the assessment of distances and reduce the risk of damage to healthy tissue. To this end, four distance-encoding visualisation concepts were developed using a head-mounted optical see-through AR setup and evaluated by conducting a comparison study. Results suggest the general advantage of the proposed methods compared to a blank visualisation providing no additional information. Using a Distance Sensor concept signalising the proximity of nearby structures resulted in the least time the instrument was located below 5mm to surrounding risk structures and yielded the least amount of collisions with them.},

keywords = {},

pubstate = {published},

tppubtype = {inproceedings}

}