@inproceedings{KreimeierHammerFriedmannetal.2019, author = {Kreimeier, Julian and Hammer, Sebastian and Friedmann, Daniel and Karg, Pascal and B{\"u}hner, Clemens and Bankel, Lukas and G{\"o}tzelmann, Timo}, title = {Evaluation of Different Types of Haptic Feedback Influencing the Task-based Presence and Performance in Virtual Reality}, series = {Proceedings of the 12th ACM International Conference on PErvasive Technologies Related to Assistive Environments (PETRA'19)}, booktitle = {Proceedings of the 12th ACM International Conference on PErvasive Technologies Related to Assistive Environments (PETRA'19)}, publisher = {ACM}, address = {New York, NY, USA}, isbn = {978-1-4503-6232-0}, doi = {10.1145/3316782.3321536}, pages = {289 -- 298}, year = {2019}, abstract = {Haptic feedback may support immersion and presence in virtual reality (VR) environments. The emerging market of consumer devices offers first devices which are expected to increase the degree of feeling being actually present in a virtual environment. In this paper we introduce a novel evaluation that examines the influence of different types of haptic feedback on presence and performance regarding manual tasks in VR. Therefore, we conducted a comprehensive user study involving 14 subjects, who performed throwing, stacking and object identification tasks in VR with visual (i.e., sensory substitution), vibrotactile or force feedback. We measured the degree of presence and task-related performance metrics. Our results indicate that regarding presence vibrotactile feedback outperforms haptic feedback which performs better than visual feedback only. In addition, force feedback significantly lowered the execution time for the throwing and the stacking task. In object identification tasks, the vibrotactile feedback increased the detection rates compared to the vibrotactile and force feedback, but also increased the required time of identification. Despite the inadequacies of the still young consumer technology, there were nevertheless strong indications of connections between presence, task fulfillment and the type of haptic feedback.}, language = {en} } @inproceedings{KargStoehrJonasetal.2023, author = {Karg, Pascal and St{\"o}hr, Roman and Jonas, Lisa and Kreimeier, Julian and G{\"o}tzelmann, Timo}, title = {Reflect-AR: Insights into Mirror-Based Augmented Reality Instructions to Support Manual Assembly Tasks}, series = {Proceedings of the 16th International Conference on PErvasive Technologies Related to Assistive Environments}, booktitle = {Proceedings of the 16th International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3594806.3594866}, pages = {62 -- 68}, year = {2023}, abstract = {Manual assembly tasks can be difficult and tedious without assistance. Here, augmented reality (AR) can help to ease the task load and lower the time and error rates by interactive in-situ instructions. Such approaches are often implemented by video or optical see-through AR. In order to test a system that is as low-threshold as possible and easy to implement, we developed a prototype with a mirror display supplemented by a RGB-D camera and evaluated it against an well-established AR HMD (HoloLens 2). For this purpose, in our study 10 participants placed 3D printed bricks via both technologies. The quantitative and qualitative analysis revealed that the fulfillment of this task with a professional, established product AR HMD yet remains unmatched in terms of the time required, error rate, usability and task load due to the prototype status and the remaining technical shortcomings. However, the mirror display setup prototype met with interest from the participants as a novel, but unfamiliar and thus more difficult to use way of interaction. Furthermore, we report implementation challenges and advises. The empirical insights of our prototype and the first-time comparison to an established AR HMD aims to foster refining future work with half-silvered AR mirrors as an little researched field and many different fields of application.}, language = {en} } @inproceedings{LyKargKreimeieretal.2022, author = {Ly, Kim and Karg, Pascal and Kreimeier, Julian and G{\"o}tzelmann, Timo}, title = {Development and Evaluation of a Low-cost Wheelchair Simulator for the Haptic Rendering of Virtual Road Conditions}, series = {Proceedings of the 15th International Conference on PErvasive Technologies Related to Assistive Environments}, booktitle = {Proceedings of the 15th International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3529190.3529195}, pages = {32 -- 39}, year = {2022}, abstract = {Many streets and buildings are not accessible for wheelchair users, which impedes a major challenge for their mobility. Often, such challenges can be considered during the planning stage, which is why it is important to include this user group in the planning process. Ideally, these planning efforts should also be made visually and haptically navigable using Virtual Reality (VR) technology to allow for better imagination, accurate conclusions, and awareness of wheelchair users. This work optimizes previous approaches so that different roadway conditions can be made haptically perceptible. The proposed prototype provides a non-contact and adjustable brake for simulating inclined planes, which can be adjusted depending on personal and environmental parameters. In addition, it can simulate roads such as cobblestones using a tactile transducer. The individually optimized components were combined into a complete VR system and integrated into a virtual environment for evaluation. The qualitative and quantitative results showed that realistic simulation is possible, but further development steps towards holistic and dissemination-capable hardware and software are needed. To this end, our contribution aims to improve the long-term involvement of wheelchair users in planning processes and increase awareness of their mobility situation.}, language = {en} } @inproceedings{KargKreimeierGoetzelmann2021, author = {Karg, Pascal and Kreimeier, Julian and G{\"o}tzelmann, Timo}, title = {Build-and-Touch: A Low-Cost, DIY, Open-Source Approach Towards Touchable Virtual Reality}, series = {Proceedings of the 14th PErvasive Technologies Related to Assistive Environments Conference}, booktitle = {Proceedings of the 14th PErvasive Technologies Related to Assistive Environments Conference}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3453892.3462217}, pages = {258 -- 259}, year = {2021}, abstract = {Virtual Reality (VR) is attracting more and more attention from academic research and practical application with the current availability of low-cost and end-user friendly devices. In terms of haptic (rather than visual) interaction, however, this technology is still in its infancy and there are few devices that are inexpensive and technologically simple to operate, respectively to procure. In this context, we present a concept of how haptic interaction with VR data gloves can also succeed by means of a commercially available web cam, sophisticated tracking software, and homemade low-cost hardware. All hardware and software components are to be obtained inexpensively or are open-source in order to achieve the greatest possible dissemination potential. With this work, we intend to provide an important trigger for future improvements and dissemination in terms of both technology and areas of application.}, language = {en} } @inproceedings{GoetzelmannKreimeierSchwabletal.2021, author = {G{\"o}tzelmann, Timo and Kreimeier, Julian and Schwabl, Johannes and Karg, Pascal and Oumard, Christina and B{\"u}ttner, Florian}, title = {AmI-VR: An Accessible Building Information System as Case Study Towards the Applicability of Ambient Intelligence in Virtual Reality}, series = {Mensch und Computer 2021}, booktitle = {Mensch und Computer 2021}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3473856.3474032}, pages = {597 -- 600}, year = {2021}, abstract = {Ambient intelligence represents a paradigm in which the user does not react to the environment, but vice versa. Accordingly, smart environments can react to the presence and activities of users and support them unobtrusively from the background. Especially in the context of accessibility, this offers great potential that has so far only been demonstrated for individual user groups. To overcome this limitation, we propose the automated, user- and context-related adaptation of the modality as well as locality of the representation of building information in the form of both an adjustable table as well as two displays on the basis of a prototype for a library information center. For being independent from material and regulatory restrictions and for better planability (especially with the ongoing COVID-19 pandemic) we used in addition to the hardware components also a Virtual Reality simulation, which proved to be very useful. Further optimization and evaluation will be needed for a more in depth understanding and dissemination in the long run, yet our prototype aims to help fostering further activities in the field of ambient intelligence, accessibility and virtual reality as a planning tool.}, language = {en} } @inproceedings{KreimeierKargGoetzelmann2020, author = {Kreimeier, Julian and Karg, Pascal and G{\"o}tzelmann, Timo}, title = {Tabletop virtual haptics}, series = {Proceedings of the 13th ACM International Conference on PErvasive Technologies Related to Assistive Environments}, booktitle = {Proceedings of the 13th ACM International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3389189.3389194}, pages = {1 -- 10}, year = {2020}, abstract = {When thinking of Virtual Reality (VR), most people think of stunning audio-visual environments in the context of entertainment. However, VR can also provide haptic information, e.g., to convey spatial information to blind and visually impaired people. In this context of accessibility they might be able to explore independently and self-determined tactile graphics, e.g., the structure of unknown real places prior to visiting them. Thus, we propose and evaluate tabletop virtual objects that can be felt by nowadays commercially available VR components, instead of exploring physical models (e.g., 3D printed maps) with the bare hand. These can be easily placed on an empty table, giving the blind user faster and more independent access to tactile information than with real physical representations. Our comprehensive pilot user study shows that it is possible to recognize floor plans and simple geometric shapes in this context. Also, the insights gained with regard to the suitability for practical application in this context point out the way to eased access to spatial (virtual) information using off-the-shelf components which can significantly support blind and visually impaired users' autonomy.}, language = {en} } @inproceedings{KreimeierKargGoetzelmann2020, author = {Kreimeier, Julian and Karg, Pascal and G{\"o}tzelmann, Timo}, title = {BlindWalkVR}, series = {Proceedings of the 13th ACM International Conference on PErvasive Technologies Related to Assistive Environments}, booktitle = {Proceedings of the 13th ACM International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3389189.3389193}, pages = {1 -- 8}, year = {2020}, abstract = {Virtual Reality (VR) promises expanded access to spatial information, especially for blind and visually impaired people. Through haptic and acoustic feedback, real world's limitations like the risk of injury or the necessity of a sighted safety assistant can be circumvented. However, the best possible profit of this technology requires interactive locomotion in large virtual environments to overcome real world space limitations. Thus, we present formative insights of blind people's egocentric VR locomotion by comparing four different implementations (i.e., two VR treadmills, trackers on the ankles or joystick based locomotion) in a qualitative and quantitative user study with seven blind and visually impaired participants. Our results reveal novel insights on characteristics of each implementation in terms of usability and practicability and also provide recommendations for further work in this field with the target user group in sight.}, language = {en} } @inproceedings{GoetzelmannKargMueller2025, author = {G{\"o}tzelmann, Timo and Karg, Pascal and M{\"u}ller, Mareike}, title = {A Novel Concept using Mirror Displays for Ambient User Notifications}, publisher = {ACM}, doi = {10.1145/3733155.3733206}, pages = {315-323}, year = {2025}, abstract = {This paper presents a novel approach to notify users about tasks in their immediate environment. Our approach is consciously designed to be low-threshold, by using augmented mirror displays, no devices such as AR glasses or smartphones have to be worn or hold by the user. The mirror display allows people passing by to get awareness of which technical and non-technical objects that need attention in an unobtrusive way. These are conveyed visually in a uniform manner and can be easily observed by passing users. If the user decides to interact by slowing down or pausing, the display adapts to more detailed information about the augmented objects. Users can decide whether this is relevant to them or not. We present a novel interaction concept, several use cases, an implementation of our approach in a laboratory scenario and conduct a user study to evaluate the feasibility and effectiveness of our interaction concept. The results reveal a good performance of our system and based on this, open up new questions perspectives for future enhancements.}, language = {en} } @article{GoetzelmannKargMueller2025, author = {G{\"o}tzelmann, Timo and Karg, Pascal and M{\"u}ller, Mareike}, title = {Augminded: Ambient Mirror Display Notifications}, series = {Multimodal Technologies and Interaction}, volume = {9}, journal = {Multimodal Technologies and Interaction}, number = {9}, publisher = {MDPI}, address = {Basel, Switzerland}, issn = {2414-4088}, doi = {10.3390/mti9090093}, pages = {22}, year = {2025}, abstract = {This paper presents a new approach for providing contextual information in real-world environments. Our approach is consciously designed to be low-threshold; by using mirrors as augmented reality surfaces, no devices such as AR glasses or smartphones have to be worn or held by the user. It enables technical and non-technical objects in the environment to be visually highlighted and thus subtly draw the attention of people passing by. The presented technology enables the provision of information that can be viewed in more detail by the user if required by slowing down their movement. Users can decide whether this is relevant to them or not. A prototype system was implemented and evaluated through a user study. The results show a high level of acceptance and intuitive usability of the system, with participants being able to reliably perceive and process the information displayed. The technology thus offers promising potential for the unobtrusive and context-sensitive provision of information in various application areas. The paper discusses limitations of the system and outlines future research directions to further optimize the technology and extend its applicability.}, language = {en} }