Browsing by Author "Stuerzlinger, Wolfgang"

Now showing 1 - 13 of 13

Citation Count: 0
Effect of Grip Style on Peripersonal Target Pointing in VR Head Mounted Displays
(Ieee Computer Soc, 2023) Batmaz, Anıl Ufuk; Turkmen, Rumeysa; Sarac, Mine; Machuca, Mayra Donaji Barrera; Stuerzlinger, Wolfgang
When working in Virtual Reality (VR), the user's performance is affected by how the user holds the input device (e.g., controller), typically using either a precision or a power grip. Previous work examined these grip styles for 3D pointing at targets at different depths in peripersonal space and found that participants had a lower error rate with the precision grip but identified no difference in movement speed, throughput, or interaction with target depth. Yet, this previous experiment was potentially affected by tracking differences between devices. This paper reports an experiment that partially replicates and extends the previous study by evaluating the effect of grip style on the 3D selection of nearby targets with the same device. Furthermore, our experiment re-investigates the effect of the vergence-accommodation conflict (VAC) present in current stereo displays on 3D pointing in peripersonal space. Our results show that grip style significantly affects user performance. We hope that our results are useful for researchers and designers when creating virtual environments.
Citation Count: 4
Effect of Stereo Deficiencies on Virtual Distal Pointing
(Assoc Computing Machinery, 2022) Batmaz, Anıl Ufuk; Mughrabi, Moaaz Hudhud; Machuca, Mayra Donaji Barrera; Stuerzlinger, Wolfgang
Previous work has shown that the mismatch between disparity and optical focus cues, i.e., the vergence and accommodation conflict (VAC), affects virtual hand selection in immersive systems. To investigate if the VAC also affects distal pointing with ray casting, we ran a user study with an ISO 9241:411 multidirectional selection task where participants selected 3D targets with three different VAC conditions, no VAC, i.e., targets placed roughly at 75 cm, which matches the focal plane of the VR headset, constant VAC, i.e., at 400 cm from the user, and varying VAC, where the depth distance of targets changed between 75 cm and 400 cm. According to our results, the varying VAC condition requires the most time and decreases the throughput performance of the participants. It also takes longer for users to select targets in the constant VAC condition than without the VAC. Our results show that in distal pointing placing objects at different depth planes has detrimental effect on the user performance.
Citation Count: 9
The Effect of the Vergence-Accommodation Conflict on Virtual Hand Pointing in Immersive Displays
(Assoc Computing Machinery, 2022) Batmaz, Anıl Ufuk; Machuca, Mayra Donaji Barrera; Sun, Junwei; Stuerzlinger, Wolfgang
Previous work hypothesized that for Virtual Reality (VR) and Augmented Reality (AR) displays a mismatch between disparities and optical focus cues, known as the vergence and accommodation conflict (VAC), affects depth perception and thus limits user performance in 3D selection tasks within arm's reach (peri-personal space). To investigate this question, we built a multifocal stereo display, which can eliminate the influence of the VAC for pointing within the investigated distances. In a user study, participants performed a virtual hand 3D selection task with targets arranged laterally or along the line of sight, with and without a change in visual depth, in display conditions with and without the VAC. Our results show that the VAC influences 3D selection performance in common VR and AR stereo displays and that multifocal displays have a positive effect on 3D selection performance with a virtual hand.
Citation Count: 1
Evaluation of an Immersive COVID-19 Data Visualization
(IEEE Computer Soc, 2023) Batmaz, Anıl Ufuk; Celik, Elif; Batmaz, Anil Ufuk K.; Mutasim, Aunnoy K.; Stuerzlinger, Wolfgang
COVID-19 restrictions have detrimental effects on the population, both socially and economically. However, these restrictions are necessary as they help reduce the spread of the virus. For the public to comply, easily comprehensible communication between decision makers and the public is thus crucial. To address this, we propose a novel 3-D visualization of COVID-19 data, which could increase the awareness of COVID-19 trends in the general population. We conducted a user study and compared a conventional 2-D visualization with the proposed method in an immersive environment. Results showed that the our 3-D visualization approach facilitated understanding of the complexity of COVID-19. A majority of participants preferred to see the COVID-19 data with the 3-D method. Moreover, individual results revealed that our method increases the engagement of users with the data. We hope that our method will help governments to improve their communication with the public in the future.
Citation Count: 0
Eye-Hand Coordination Training: A Systematic Comparison of 2D, VR, and AR Display Technologies and Task Instructions
(Ieee Computer Soc, 2024) Batmaz, Anıl Ufuk; Zaugg, Irene; Celik, Elif; Stuerzlinger, Wolfgang; Ortega, Francisco Raul; Batmaz, Anil Ufuk; Sarac, Mine
Previous studies on Eye-Hand Coordination Training (EHCT) focused on the comparison of user motor performance across different hardware with cross-sectional studies. In this paper, we compare user motor performance with an EHCT setup in Augmented Reality (AR), Virtual Reality (VR), and on a 2D touchscreen display in a longitudinal study. Through a ten-day user study, we thoroughly analyzed the motor performance of twenty participants with five task instructions focusing on speed, error rate, accuracy, precision, and none. As a novel evaluation criterion, we also analyzed the participants' performance in terms of effective throughput. The results showed that each task instruction has a different effect on one or more psychomotor characteristics of the trainee, which highlights the importance of personalized training programs. Regarding different display technologies, the majority of participants could see more improvement in VR than in 2D or AR. We also identified that effective throughput is a good candidate for monitoring overall motor performance progress in EHCT systems.
Citation Count: 0
EyeGuide & EyeConGuide: Gaze-based Visual Guides to Improve 3D Sketching Systems
(Assoc Computing Machinery, 2024) Batmaz, Anıl Ufuk; Gelmez, Zeynep Ecem; Batmaz, Anil Ufuk; Stuerzlinger, Wolfgang; Asente, Paul; Sarac, Mine
Visual guides help to align strokes and raise accuracy in Virtual Reality (VR) sketching tools. Automatic guides that appear at relevant sketching areas are convenient to have for a seamless sketching with a guide. We explore guides that exploit eye-tracking to render them adaptive to the user's visual attention. EYEGUIDE and EYECONGUIDE cause visual grid fragments to appear spatially close to the user's intended sketches, based on the information of the user's eye-gaze direction and the 3D position of the hand. Here we evaluated the techniques in two user studies across simple and complex sketching objectives in VR. The results show that gaze-based guides have a positive effect on sketching accuracy, perceived usability and preference over manual activation in the tested tasks. Our research contributes to integrating gaze-contingent techniques for assistive guides and presents important insights into multimodal design applications in VR.
Citation Count: 0
The Guided Evaluation Method: An easier way to empirically estimate trained user performance for unfamiliar keyboard layouts
(Academic Press Ltd- Elsevier Science Ltd, 2024) Batmaz, Anıl Ufuk; Batmaz, Anil Ufuk; Mughrabi, Moaaz Hudhud; Stuerzlinger, Wolfgang
To determine in a user study whether proposed keyboard layouts, such as OPTI, can surpass QWERTY in performance, extended training through longitudinal studies is crucial. However, addressing the challenge of creating trained users presents a logistical bottleneck. A common alternative involves having participants type the same word or phrase repeatedly. We conducted two separate studies to investigate this alternative. The findings reveal that both approaches, repeatedly typing words or phrases, have limitations in accurately estimating trained user performance. Thus, we propose the Guided Evaluation Method (GEM), a novel approach to quickly estimate trained user performance with novices. Our results reveal that in a matter of minutes, participants exhibited performance similar to an existing longitudinal study - OPTI outperforms QWERTY. As it eliminates the need for resource-intensive longitudinal studies, our new GEM thus enables much faster estimation of trained user performance. This outcome will potentially reignite research on better text entry methods.
Citation Count: 3
Measuring the Effect of Stereo Deficiencies on Peripersonal Space Pointing
(IEEE Computer Soc, 2023) Batmaz, Anıl Ufuk; Mughribi, Moaaz Hudhud; Sarac, Mine; Machuca, Mayra Barrera; Stuerzlinger, Wolfgang
State-of-the-art Virtual Reality (VR) and Augmented Reality (AR) headsets rely on singlefocal stereo displays. For objects away from the focal plane, such displays create a vergence-accommodation conflict (VAC), potentially degrading user interaction performance. In this paper, we study how the VAC affects pointing at targets within arm's reach with virtual hand and raycasting interaction in current stereo display systems. We use a previously proposed experimental methodology that extends the ISO 9241-411:2015 multi-directional selection task to enable fair comparisons between selecting targets in different display conditions. We conducted a user study with eighteen participants and the results indicate that participants were faster and had higher throughput in the constant VAC condition with the virtual hand. We hope that our results enable designers to choose more efficient interaction methods in virtual environments.
Citation Count: 9
My Eyes Hurt: Effects of Jitter in 3D Gaze Tracking
(IEEE Computer Soc, 2022) Batmaz, Anıl Ufuk; Mutasim, Aunnoy K.; Stuerzlinger, Wolfgang; Batmaz, Anil Ufuk
Jitter, small fluctuations in the signal, is one of the major sources for a decrease in motor performance and a negative user experience in virtual reality (VR) systems. Current technologies still cannot eliminate jitter in VR systems, especially in the eye-gaze tracking systems embedded in many head-mounted displays. In this work, we used an HTC Vive Pro Eye, artificially added 0.5 degrees, 1 degrees, and 1.5 degrees jitter to the eye-tracking data, and analyzed user performance in an ISO 9241:411 pointing task with targets at 1 or 2 meters visual distance using angular Fitts' law. The results showed that the user's error rate significantly increases with increased jitter levels. No significant difference was observed for time and throughput. Additionally, we observed a significant decrease in performance in terms of time, error rate, and accuracy for the more distant targets. We hope that our results guide researchers, practitioners, and developers towards better gaze-tracking-based VR applications.
Citation Count: 1
On the Effectiveness of Virtual Eye-Hand Coordination Training with Head Mounted Displays
(IEEE Computer Soc, 2023) Batmaz, Anıl Ufuk; Kaya, Furkan; Batmaz, Anil Ufuk; Aliza, Aliza; Stuerzlinger, Wolfgang; Borazan, Baris; Tonyali, Emir
Eye-hand coordination training systems are used to train participants' motor skills and visual perception. Such systems have already been tested in Virtual Reality, and the results revealed that Head Mounted Display-based systems have the potential to improve the motor training. However. this was only investigated in an hour-long study. In the longitudinal study reported here, we analyzed the motor performance of three participants in ten sessions with three different assessment criteria, where participants were instructed to focus on speed, error rate, or complete the training freely (with no instructions). We also assessed the effective throughput performance of the participants. Our results indicate that effective throughput can be potentially used as an additional assessment criterion, We hope that our results will help practitioners and developers design efficient Virtual Reality training systems.
Citation Count: 2
Performance Analysis of Saccades for Primary and Confirmatory Target Selection
(Assoc Computing Machinery, 2022) Batmaz, Anıl Ufuk; Batmaz, Anil Ufuk; Mughrabi, Moaaz Hudhud; Stuerzlinger, Wolfgang
In eye-gaze-based selection, dwell suffers from several issues, e.g., the Midas Touch problem. Here we investigate saccade-based selection techniques as an alternative to dwell. First, we designed a novel user interface (UI) for Actigaze and used it with ( goal-crossing) saccades for confirming the selection of small targets (i.e., < 1.5-2 degrees). We compared it with three other variants of Actigaze (with button press, dwell, and target reverse crossing) and two variants of target magnification (with button press and dwell). Magnification-dwell exhibited the most promising performance. For Actigaze, goal-crossing was the fastest option but suffered the most errors. We then evaluated goal-crossing as a primary selection technique for normal-sized targets (>= 2 degrees) and implemented a novel UI for such interaction. Results revealed that dwell achieved the best performance. Yet, we identified goal-crossing as a good compromise between dwell and button press. Our findings thus identify novel options for gaze-only interaction.
Citation Count: 2
Re-investigating the Effect of the Vergence-Accommodation Conflict on 3D Pointing
(Assoc Computing Machinery, 2023) Batmaz, Anıl Ufuk; Turkmen, Rumeysa; Sarac, Mine; Machuca, Mayra Donaji Barrera; Stuerzlinger, Wolfgang
The vergence-accommodation conflict (VAC) limits user performance in current Virtual Reality (VR) systems. In this paper, we investigate the effects of the VAC in a single-focal VR system using three experimental conditions: with no VAC, with a constant VAC, and with a varying VAC. Previous work in this area had yielded conflicting results, so we decided to re-investigate this issue. Eighteen participants performed an ISO 9241:411 task in a study that closely replicates previous work, except that the angle of the task space was rotated 20 degrees downward, to make the task less fatiguing to perform, which addresses a potential confound in previous work. We found that the varying VAC condition had worse performance than the other conditions, which indicates that the contrasting results in previous work were very likely due to biomechanical factors. We hope that our work contributes to the understanding of the influence of the VAC in VR systems and potential strategies for improving user experience and performance in immersive virtual environments.
Citation Count: 0
The Role of the Depth Dimension in 3D Visualizations for Dense Data Understanding
(Sage Publications Ltd, 2022) Batmaz, Anıl Ufuk; Batmaz, Anil Ufuk; Mutasim, Aunnoy K.; Stuerzlinger, Wolfgang
[Abstract Not Available]