Browsing by Author "Batmaz, Anil Ufuk"

Now showing 1 - 20 of 21

Citation - WoS: 21
Citation - Scopus: 22
My Eyes Hurt: Effects of Jitter in 3D Gaze Tracking
(IEEE Computer Soc, 2022) Mughrabi, Moaaz Hudhud; 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.
The Role of the Depth Dimension in 3D Visualizations for Dense Data Understanding
(Sage Publications Ltd, 2022) Kaya, Furkan; Batmaz, Anil Ufuk; Mutasim, Aunnoy K.; Stuerzlinger, Wolfgang
[Abstract Not Available]
Citation - WoS: 15
Citation - Scopus: 20
Re-Investigating the Effect of the Vergence-Accommodation Conflict on 3d Pointing
(Assoc Computing Machinery, 2023) Batmaz, Anil 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 - WoS: 1
Citation - Scopus: 3
Subtask-Based Virtual Hand Visualization Method for Enhanced User Accuracy in Virtual Reality Environments
(Ieee Computer Soc, 2024) Voisard, Laurent; Hatira, Amal; Bashar, Mohammad Raihanul; Gemici, Mucahit; Sarac, Mine; Kersten-Oertel, Marta; Batmaz, Anil Ufuk
In the virtual hand interaction techniques, the opacity of the virtual hand avatar can potentially obstruct users' visual feedback, leading to detrimental effects on accuracy and cognitive load. Given that the cognitive load is related to gaze movements, our study focuses on analyzing the gaze movements of participants across opaque, transparent, and invisible hand visualizations in order to create a new interaction technique. For our experimental setup, we used a Purdue Pegboard Test with reaching, grasping, transporting, and inserting subtasks. We examined how long and where participants concentrated on these subtasks and, using the findings, introduced a new virtual hand visualization method to increase accuracy. We hope that our results can be used in future virtual reality applications where users have to interact with virtual objects accurately.
Citation - WoS: 36
Citation - Scopus: 51
The Effect of the Vergence-Accommodation Conflict on Virtual Hand Pointing in Immersive Displays
(Assoc Computing Machinery, 2022) Batmaz, Anil 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 - WoS: 7
Citation - Scopus: 9
Measuring the Effect of Stereo Deficiencies on Peripersonal Space Pointing
(IEEE Computer Soc, 2023) Batmaz, Anil 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 - WoS: 1
Citation - Scopus: 1
The Influence of Eye Gaze Interaction Technique Expertise and the Guided Evaluation Method on Text Entry Performance Evaluations
(Assoc Computing Machinery, 2025) Mutasim, Aunnoy K.; Batmaz, Anil Ufuk; Mughrabi, Moaaz Hudhud; Stuerzlinger, Wolfgang
Any investigation of learning unfamiliar text entry systems is affected by the need to train participants on multiple new components simultaneously, such as novel interaction techniques and layouts. The Guided Evaluation Method (GEM) addresses this challenge by bypassing the need to learn layout-specific skills for text entry. However, a gap remains as the GEM's performance has not been assessed in situations where users are unfamiliar with the interaction technique involved, here eye-gaze-based dwell. To address this, we trained participants on only the eye-gaze-based interaction technique over eight days with QWERTY and then evaluated their performance on the OPTI layout with the GEM. Results showed that the unfamiliar OPTI layout outperformed QWERTY, with QWERTY's speed aligning with previous findings, suggesting that interaction technique expertise significantly impacts performance outcomes. Importantly, we also identified that for scenarios where the familiarity with the involved interaction technique(s) is the same, the GEM analyzes the performance of keyboard layouts effectively and quickly identifies the best option.
Citation - WoS: 2
Citation - Scopus: 2
Effects of Color Cues on Eye-Hand Coordination Training With a Mirror Drawing Task in Virtual Environment
(Frontiers Media Sa, 2024) Alrubaye, Zainab; Mughrabi, Moaaz Hudhud; Manav, Banu; Batmaz, Anil Ufuk
Mirror drawing is a motor learning task that is used to evaluate and improve eye-hand coordination of users and can be implemented in immersive Virtual Reality (VR) Head-Mounted Displays (HMDs) for training purposes. In this paper, we investigated the effect of color cues on user motor performance in a mirror-drawing task between Virtual Environment (VE) and Real World (RW), with three different colors. We conducted a 5-day user study with twelve participants. The results showed that the participants made fewer errors in RW compared to VR, except for pre-training, which indicated that hardware and software limitations have detrimental effects on the motor learning of the participants across different realities. Furthermore, participants made fewer errors with the colors close to green, which is usually associated with serenity, contentment, and relaxation. According to our findings, VR headsets can be used to evaluate participants' eye-hand coordination in mirror drawing tasks to evaluate the motor-learning of participants. VE and RW training applications could benefit from our findings in order to enhance their effectiveness.
Citation - WoS: 3
Citation - Scopus: 5
Effect of Grip Style on Peripersonal Target Pointing in Vr Head Mounted Displays
(Ieee Computer Soc, 2023) Batmaz, Anil 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 - WoS: 3
Exploring Discrete Drawing Guides To Assist Users in Accurate Mid-Air Sketching in Vr
(Assoc Computing Machinery, 2022) Turkmen, Rumeysa; Pfeuffer, Ken; Machuca, Mayra Donaji Barrera; Batmaz, Anil Ufuk; Gellersen, Hans
Even though VR design applications that support sketching are popular, sketching accurately in mid-air is challenging for users. In this paper, we explore discrete visual guides that assist users' stroke accuracy and drawing experience inside the virtual environment. We also present an eye-tracking study that compares continuous, discrete, and no guide in a basic drawing task. Our experiment asks participants to draw a circle and a line using three different guide types, three different sizes and two different orientations. Results indicate that discrete guides are more user-friendly than continuous guides, as the majority of participants preferred their use, while we found no difference in speed/accuracy compared to continuous guides. Potentially, this can be attributed to distinct eye-gaze strategies, as discrete guides led users to shift their eyes more frequently between guide points and the drawing cursor. Our insights are useful for practitioners and researchers in 3D sketching, as they are a first step to inform future design applications of how visual guides inside the virtual environment affect visual behaviour and how eye-gaze can become a tool to assist sketching.
Citation - Scopus: 2
Enhancing Eye-Hand Coordination in Volleyball Players: A Comparative Analysis of VR, AR, and 2D Display Technologies and Task Instructions
(IEEE Computer SOC, 2024) Hatira, Nour; Aliza, Aliza; Batmaz, Anil Ufuk; Sarac, Mine
Previous studies analyzed user motor performance with Virtual Reality (VR) and Augmented Reality (AR) Eye-Hand Coordination Training Systems (EHCTSs) while asking participants to follow specific task instructions. Although these studies suggested VR & AR EHCTSs as potential training systems for sports players, they recruited participants for their user studies among general population. In this paper, we examined the training performance of 16 professional volleyball players over 8 days using EHCTSs with three display technologies (VR, AR, and 2D touchscreen) and with four distinct task instructions (prioritizing speed, error rate, accuracy, or none). Our results indicate that volleyball players performed best with 2D touchscreen in terms of time, error rate, accuracy, precision, and throughput. Moreover, their performance was superior when using VR over AR. They also successfully followed the task instructions given to them and consistently improved their throughput performance. These findings underscore the potential of EHCTS in volleyball training and highlight the need for further research to optimize VR & AR user experience and performance.
Depth3DSketch: Freehand Sketching Out of Arm's Reach in Virtual Reality
(Assoc Computing Machinery, 2025) Bashar, Mohammad Raihanul; Amini, Mohammadreza; Stuerzlinger, Wolfgang; Sarac, Mine; Pfeuffer, Ken; Machuca, Mayra Donaji Barrera; Batmaz, Anil Ufuk
Due to the increasing availability and popularity of virtual reality (VR) systems, 3D sketching applications have also boomed. Most of these applications focus on peripersonal sketching, e.g., within arm's reach. Yet, sketching in larger scenes requires users to walk around the virtual environment while sketching or to change the sketch scale repeatedly. This paper presents Depth3DSketch, a 3D sketching technique that allows users to sketch objects up to 2.5 m away with a freehand sketching technique. Users can select the sketching depth with three interaction methods: using the joystick on a single controller, the intersection from two controllers, or the intersection from the controller ray and the user's gaze. We compared these interaction methods in a user study. Results show that users preferred the joystick to select visual depth, but there was no difference in user accuracy or sketching time between the three methods.
Citation - WoS: 3
Citation - Scopus: 4
Effect of Hand and Object Visibility in Navigational Tasks Based on Rotational and Translational Movements in Virtual Reality
(Ieee Computer Soc, 2024) Hatira, Amal; Gelmez, Zeynep Ecem; Batmaz, Anil Ufuk; Sarac, Mine
During object manipulation in Virtual Reality (VR) systems, realistically visualizing avatars and objects can hinder user performance and experience by complicating the task or distracting the user from the environment due to possible occlusions. Users might feel the urge to go through biomechanical changes, such as re-positioning the head to visualize the interaction area. In this paper, we investigate the effect of hand avatar and object visibility in navigational tasks using a VR headset. We performed two user studies where participants grasped a small, cylindrical object and navigated it through the virtual obstacles performing rotational or translational movements. We used three different visibility conditions for the hand avatar (opaque, transparent, and invisible) and two conditions for the object (opaque and transparent). Our results indicate that participants performed faster and with fewer collisions using the invisible and transparent hands compared to the opaque hand and fewer collisions with the opaque object compared to the transparent one. Furthermore, participants preferred to use the combination of the transparent hand avatar with the opaque object. The findings of this study might be useful to researchers and developers in deciding the visibility/transparency conditions of hand avatars and virtual objects for tasks that require precise navigational activities.
Citation - WoS: 7
Citation - Scopus: 9
I Consider Vr Table Tennis To Be My Secret Weapon!: an Analysis of the Vr Table Tennis Players' Experiences Outside the Lab
(Assoc Computing Machinery, 2023) Karatas, Eren; Sunday, Kissinger; Apak, Sude Erva; Li, Yiwei; Sun, Junwei; Batmaz, Anil Ufuk
Thanks to stand-alone Virtual Reality (VR) advances, users can play realistic simulations of real-life sports at their homes. In these game simulations, players control their avatars by doing the same movements as in real life (RL) while playing against a person or AI opponent, making VR sports attractive for the players. In this paper, we surveyed a popular VR table tennis game community, focusing on understanding their demographics, challenges, and experiences with skill transfers between VR and RL. Our results show that, on average, VR table tennis players are primarily men, live in Europe/Asia, and are 38 years old. We also found that the current state of VR technology affects the player's experience and that players see VR as a convenient way to play matches but that RL is better for socialization. Finally, we identified skills like backhand and forehand strikes that players perceived to be transferred from VR to RL and vice versa. Our research findings have the potential to serve as a valuable resource for VR table tennis game developers seeking to integrate mid-air controllers into their future projects.
Citation - WoS: 12
Citation - Scopus: 13
Performance Analysis of Saccades for Primary and Confirmatory Target Selection
(Assoc Computing Machinery, 2022) Mutasim, Aunnoy K.; 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 - WoS: 5
Citation - Scopus: 9
EyeGuide & EyeConGuide: Gaze-based Visual Guides to Improve 3D Sketching Systems
(Assoc Computing Machinery, 2024) Turkmen, Rumeysa; 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 - WoS: 5
Citation - Scopus: 9
Effects of Opaque, Transparent and Invisible Hand Visualization Styles on Motor Dexterity in a Virtual Reality Based Purdue Pegboard Test
(Ieee Computer Soc, 2023) Voisard, Laurent; Hatira, Amal; Sarac, Mine; Kersten-Oertel, Marta; Batmaz, Anil Ufuk
The virtual hand interaction technique is one of the most common interaction techniques used in virtual reality (VR) systems. A VR application can be designed with different hand visualization styles, which might impact motor dexterity. In this paper, we aim to investigate the effects of three different hand visualization styles transparent, opaque, and invisible - on participants' performance through a VR-based Purdue Pegboard Test (PPT). A total of 24 participants were recruited and instructed to place pegs on the board as quickly and accurately as possible. The results indicated that using the invisible hand visualization significantly increased the number of task repetitions completed compared to the opaque hand visualization. However, no significant difference was observed in participants' preference for the hand visualization styles. These findings suggest that an invisible hand visualization may enhance performance in the VR-based PPT, potentially indicating the advantages of a less obstructive hand visualization style. We hope our results can guide developers, researchers, and practitioners when designing novel virtual hand interaction techniques.
Citation - WoS: 6
Citation - Scopus: 7
Eye-Hand Coordination Training: a Systematic Comparison of 2d, Vr, and Ar Display Technologies and Task Instructions
(Ieee Computer Soc, 2024) Aliza, Aliza; 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 - WoS: 8
Citation - Scopus: 11
Effect of Stereo Deficiencies on Virtual Distal Pointing
(Assoc Computing Machinery, 2022) Batmaz, Anil 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 - WoS: 4
Citation - Scopus: 4
The Guided Evaluation Method: an Easier Way To Empirically Estimate Trained User Performance for Unfamiliar Keyboard Layouts
(Academic Press Ltd- Elsevier Science Ltd, 2024) Mutasim, Aunnoy K.; 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.