ICAT-EGVE2023
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Item Comparison of Touchless Interaction With One and Multiple Optical Sensors(The Eurographics Association, 2023) Nováček, Tomáš; Kondac, Radoslav; Jirina, Marcel; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtIn this research, we compared the precision and ease of use of hand-tracking with one and three optical sensors. We created two test scenes that simulated real-life scenarios, one focusing on smoothness and intuitiveness and the other one focusing on precision and tracking range. We conducted tests with 25 participants and measured the precision and effectiveness of their work with basic user interface elements and 3D objects. This research showed that using multiple optical sensors for hand-tracking greatly improves the precision of the tracking, widens the tracking range and provides more smooth interaction. On average, 80% of the users preferred using three sensors for the interaction because it allowed more users to finish the tasks (74% on average) in a shorter time (15% on average) and with more precise results (43% on average) compared to same tasks done with just one sensor.Item Real-time Self-contact Retargeting of Avatars down to Finger Level(The Eurographics Association, 2023) Delahaye, Mathias; Herbelin, Bruno; Boulic, Ronan; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtWe interact with the world through a body that includes hands and fingers. Likewise, providing an avatar allowing the control of a virtual body with fingers is an important step to improve the user experience in VR. When the user and their avatar skeleton and morphology differ, the direct application of the captured user motion on the avatar's skeleton generally induces self-contact conflicts such as undesired interpenetrations or gaps. Hence it is essential to retarget on-the-fly the user's pose to prevent such mismatches. In this paper, we propose a real-time avatar control with self-contact congruency, including finger mobility. The retargeting approach is evaluated through a subjective evaluation procedure, comparing it against a full-body animation using the user's original movement. Our results show that the retargeted animation approach outperforms the avatar control through the sole captured user movement.Item Comparative Glyph-Field Trajectory Analyses with an AR+Tablet Hybrid User Interface for Geospatial Analysis Tasks(The Eurographics Association, 2023) Hu, Sathaporn; Reilly, Derek; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtAugmented reality (AR) supports large virtual display areas without the need for physical screens-affording more mobility to the user and displaying map-based data. Current head-worn AR devices have limited processing and rendering capabilities. Their hand-free input is imprecise. Hybrid interfaces, such as AR+tablet, can mitigate these limitations: the tablet can provide additional display fidelity in a region of interest and act as a precise input device. Used together, AR and a tablet support tasks that simultaneously require mobility and large area displays. However, more work is needed on such a system to understand the influence of glyph visualization techniques on glyph field scanning behaviours. Two glyph-based representations named Polyline and Mondrian were compared. Polyline is a shape-based technique known to be good for finding trends in desktop contexts. Mondrian is a colour-based technique. In theory, it is good for pre-attentive cursory exploration. Participants performed seminaturalistic tasks based on geospatial linear regression. Polyline induced more scrolling on the tablet because participants wanted to examine glyphs more closely. Mondrian induced more gaze movement across the AR display region, but tasks could also affect gaze. We then discuss focus+context, and colourmap design.Item Does the Virtual Environment Design influence Learning?(The Eurographics Association, 2023) Minder, Eloise; Chardonnet, Jean-Rémy; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtPast studies have shown that virtual reality (VR) is an advantageous medium to learn or train in various situations over traditional methods. Virtual environments are usually modeled and implemented to be representative of the training situations. However, in an objective to maximize the effectiveness and efficiency of VR for knowledge transfer, we may wonder whether the virtual environment itself really matters or not. In this paper, we propose to compare two different virtual environments implemented for the same training purpose. The scenario chosen relates to learning the right procedure to limit the spread of viruses. The two environments have been designed to be radically opposed: the first one is a dreamlike environment, while the second represents a medical laboratory. A user study was performed to compare the level of engagement and knowledge acquired by the participants in both environments. User experience, commitment, emotion and learning outcomes were measured. Results indicate no significant difference in the environment design on learning, feeling, commitment and sense of presence.Item Analyzing the Behavior of Projector-Camera Systems Based on Reaction-Diffusion Equations(The Eurographics Association, 2023) Amano, Toshiyuki; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtPixel Feedback Animation (PFA), a technique that uses projector-camera feedback, has emerged as a dynamic illumination method introducing variations in color and brightness for expressive purposes. Notably, the deliberate application of specific image processing techniques during the projector-camera feedback loop has unveiled the potential to generate patterns reminiscent of Turing patterns solutions to reaction-diffusion equations. However, the intrinsic nature of PFA's projection-camera system consists of image capture and reflective properties of the projection surface, which create illumination patterns. In this paper, a comprehensive investigation into the underlying mechanisms of PFA is presented, revealing its inherent connection to reaction-diffusion systems. The study explores the emergence of distinct PFA patterns intricately influenced by variations in object surface reflectivity and coloration.Item Consistency of Virtual Human Faces: Effect of Stylization and Expressiveness Intensity on Character Perception(The Eurographics Association, 2023) Dubosc, Charlotte; Gorisse, Geoffrey; Christmann, Olivier; Richir, Simon; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtThe perception of virtual human faces is impacted by several interrelated factors, such as shapes, materials, textures, shading or animation. Previous research demonstrated that animation flaws and inconsistencies tend to be less accepted on realistic characters compared to stylized ones. To further investigate the relationship between stylization and facial expressions, we designed an online investigation to assess participants' perception of virtual human faces with regards to perceived realism, attractiveness and eeriness. We modeled a female and a male character with three levels of stylization (stylized, semi-realistic, realistic) and four expressiveness intensities (idle, low, moderate and exaggerated). 135 participants took part in the experiment which consisted of watching a set of 24 videos lasting 30 seconds each. Interaction effects were observed between the independent variables. Overall, results indicated that perceived realism was mainly driven by the stylization level. Visually realistic characters were perceived as more realistic even with exaggerated facial expressions. In terms of attractiveness, scores tended to decrease as the intensity of facial expressions increased. At the highest expressiveness intensity, the semi-realistic female character was preferred over the stylized and the realistic ones, while the realistic male character scored higher than the others. In line with previous studies, results indicated that perceived eeriness rises with the intensities of facial expressions. Taken as a whole, this study provides valuable guidelines for 3D artists and developers to design avatars and autonomous agents.Item Mid-air Image's Background Changes the Impression of a Mid-air Image(The Eurographics Association, 2023) Yano, Yutaro; Koizumi, Naoya; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtPrevious research in perceptual science has shown that peripheral information can easily change the perception of an object. However, mid-air images are rarely used as targets in such studies. In this study, we placed the ground below a mid-air image and investigated how changing the ground image affected the perception of the mid-air image. Specifically, we confirmed through psychophysical experiments that shadow length variation changes depth perception (Experiment 1) and that the relative motion of a mid-air image and the ground image changes speed perception (Experiment 2). The results of Experiment 1 showed that increasing the shadow length from its exact value increased the perceived depth of the mid-air image by 16% while decreasing the shadow length from its exact value decreased the perceived depth of the mid-air image by 26%. The results of Experiment 2 showed that the perceived speed of the mid-air image when the ground was moving in the opposite direction of the mid-air image was 58% faster than the perceived speed when the ground was moving in the same direction. We expect that the grounds created in this study can extend the range of depth and speed perception in content designs using mid-air images.Item Can You Find Your Way? Comparing Wayfinding Behaviour Between Reality and Virtual Reality(The Eurographics Association, 2023) Goupil, Vincent; Arnaldi, Bruno; Argelaguet, Ferran; Michaud, Anne-Solène; Gouranton, Valérie; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtSignage is an essential element in finding one's way and avoiding getting lost in open and indoor environments. Yet, designing an effective signage system for a complex structure remains a challenge, as some buildings may need to communicate a lot of information in a minimum amount of space. Virtual reality (VR) provides a new way of studying human wayfinding behaviour, offering a flexible and cost-effective platform for assessing the efficiency of signage, especially during the design phase of a building. However, it is not yet clear whether wayfinding behaviour and signage interpretation differ between reality and virtual reality. We conducted a wayfinding experiment using signage with 20 participants who performed a series of tasks in virtual and real conditions. Participants were video-recorded in both conditions. In addition, oral feedback and post-experiment questionnaires were collected as supplementary data. The aim of this study was to investigate the wayfinding behaviour of a user using signs in an unfamiliar real and virtual environment. The results of the experiment showed a similarity in behaviour between both environments; regardless of the order of passage and the environment, participants required less time to complete the task during the second run by reducing their mistakes and learning from their first run.Item ICAT-EGVE 2023 - International Conference on Artificial Reality and Telexistence and Eurographics Symposium on Virtual Environments(The Eurographics Association, 2023) Jean-Marie Normand; Maki Sugimoto; Veronica Sundstedt; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtItem Don't Denigrate the CAVE! A Comparative Examination of CAVE and HMD for Navigation in Virtual Worlds(The Eurographics Association, 2023) Combe, Theo; Chardonnet, Jean-Rémy; Mérienne, Frédéric; Ovtcharova, Jivka; Mestre, Daniel; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtThis paper conducts a comprehensive analysis of user experiences by comparing navigation and cybersickness between two distinct categories of immersive devices: CAVE and HMD. Using consistent methodology and analysis for both technologies in the same application to underscores disparities in user experiences, particularly in navigation and exploration tasks, addressing a gap in the existing literature. The study comprises two experiments with differing navigation paradigms. The first demanded active participant navigation in a complex virtual environment, focusing on distinctions like field of view and field of regard intrinsic to CAVE and HMD technologies. Physiological parameters (heart rate and skin conductance) and the Virtual Reality Sickness Questionnaire (VRSQ) were recorded to assess cybersickness levels. Results indicate no significant variations in self-rated cybersickness but a higher heart rate for HMD and longer completion time in the CAVE. Participants favored HMDs personally. In the second experiment, participants were guided through an automated virtual environment (VE) walk, recording similar physiological and psychological measurements. Although no significant inter-device variations emerged in psychological measurements, a notable influence of the HMD on physiological cybersickness data and postural stability was observed. Nevertheless, other measurements and participant feedback did not align with substantial cybersickness. Overall, our results provide a better understanding of the differences between these two VR displays.Item Stacked Dual Attention for Joint Dependency Awareness in Pose Reconstruction and Motion Prediction(The Eurographics Association, 2023) Guinot, Lena; Matsumoto, Ryutaro; Iwata, Hiroyasu; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtHuman pose reconstruction and motion prediction in real-time environments have become pivotal areas of research, especially with the burgeoning applications in Virtual and Augmented Reality (VR/AR). This paper presents a novel deep neural network underpinned by a stacked dual attention mechanism, effectively leveraging data from just 6 Inertial Measurement Units (IMUs) to reconstruct human full body poses. While previous works have predominantly focused on image-based techniques, our approach, driven by the sparsity and versatility of sensors, taps into the potential of sensor-based motion data collection. Acknowledging the challenges posed by the under-constrained nature of IMU data and the inherent limitations in available open-source datasets, we innovatively transform motion capture data into an IMU-compatible format. Through a holistic understanding of joint dependencies and temporal dynamics, our method promises enhanced accuracy in motion prediction, even in uncontrolled environments typical of everyday scenarios. Benchmarking our model against prevailing methods, we underscore the superiority of our dual attention mechanism, setting a new benchmark for real-time motion prediction using minimalistic sensor arrangements.Item Exploring the Perception of Center of Mass changes for VR Avatars(The Eurographics Association, 2023) Vyas, Bharat; Hoyet, Ludovic; O'Sullivan, Carol; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtPopulating Virtual Environments with animated virtual characters often involves retargeting motions to 3D body models with differing shapes. A user's avatar, for example, should move in a way that is consistent with their model's body shape in order to maintain the sense of presence. We present a set of perception experiments to explore how motions captured from actors with various body mass indices (BMI) are perceived, when they are retargeted to characters with different BMIs. We also explored the perceptual effects of retargeting average and physics-based motions. To explore the latter, we devised a physics-based controller framework that utilizes motion, target body weight, and height as inputs to generate retargeted motions. Despite the controller generating varied motions for various body shapes, average motions consistently outperformed the controllergenerated motions in terms of naturalness. Overall, this work highlights an anthropometric based physics controller and a novel approach for perceptual evaluation of human motion retargeting for virtual characters.Item 4D Exploring System for Intuitive Understanding of 4D Space by Extending Familiar 3D Interfaces(The Eurographics Association, 2023) Igarashi, Haruo; Sawada, Hideyuki; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtWith the advancement of VR technology and the increasing demand for high-dimensional data, a variety of intuitive visualization and interaction methods for high-dimensional data have been proposed. In this paper, we propose a new 4D space interaction system aimed at not only being more intuitive but also making it easier for non-experts to understand 4D space. The proposed system functions as a familiar system for exploring 3D space, and when exploring the 4D space, a user is able to directly leverage the operations used for navigating the 3D space. This feature is achieved through a combination of displaying crosssections of 4D space by slicing through 3D screens and intuitive operation using motion controllers. By moving back and forth between exploring the 4D space and the 3D cross-sections, a user can observe and experience the relationships, aiding in the understanding of 4D space. From the maze exploration experiments, not only were promising results obtained, but interesting insights were also garnered regarding the field of high-dimensional space perception, an area with many unresolved aspects.Item Embodied Conversational Agents with Situation Awareness for Training in Virtual Reality(The Eurographics Association, 2023) Kán, Peter; Rumpelnik, Martin; Kaufmann, Hannes; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtEmbodied conversational agents have a great potential in virtual reality training applications. This paper investigates the impact of conversational agents on users in a first responder training scenario. We integrated methods for automatic speech recognition and speech synthesis with natural language processing into a VR training application in the Unity game engine. Additionally, we present a method for enabling situation awareness for agents in a virtual environment. Finally, we conducted a between-subject lab experiment with 24 participants which investigated differences between conversational agents and agents with pre-scripted audio. Several metrics were measured in the experiment including presence, subjective task performance, learning outcome, interaction quality, quality of information presentation, perceived realism, co-presence, and training task duration. Our results suggest that users trying our conversational agents condition experienced significantly higher level of copresence than users with pre-scripted audio. Additionally, significant differences in subjective task performance and training duration were discovered between genders. Based on the results of our qualitative analysis, we provide guidelines that can facilitate future design of VR training applications and research studies with embodied conversational agents.Item Insights From a Study on Subtle Mimicry in Human-Agent Interaction(The Eurographics Association, 2023) Ungruh, Robin; Schmidt, Susanne; Norouzi, Nahal; Steinicke, Frank; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtIn social interactions, people tend to imitate the behavior of others and to perceive dialogues in which they are imitated to be more natural and smooth. This process of mimicry is not limited to non-verbal behavior, but also involves subtle adaptation of one's own speech style to the communication partner. Although being a natural phenomenon in human-human interaction, it is not yet common for virtual agents to simulate such behavior by adapting their speech style to that of the user. This work presents a user study (N = 48) that explores the participants' perception of a virtual agent mimicking formal and informal speech. The majority of participants preferred agents with a matching speech style over those with a mismatching one. Other positive results of mimicry that were previously found in human-human interaction could not be replicated. To inform other researchers studying subtle agent behavior about possible factors that might dominate participants' perception of an agent, we present the results of a thorough content analysis of qualitative user feedback. From the salient themes, such as mismatched emotionality in language and speech, affordances of agents, and expectations of the agent's role in interactions, we derive recommendations for the design of future user studies of subtle (verbal and non-verbal) agent behavior.Item 3D Computer Graphics-Based Grass Pixel Simulation System for Color Scale Mapping Method(The Eurographics Association, 2023) Mizuno, Akito; Tanaka, Kojiro; Mikawa, Masahiko; Fujisawa, Makoto; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtRecently, a wide range of media devices have been developed, with increasing emphasis on activities related to media art using natural elements. Although numerous studies have been conducted to harmonize media devices with natural landscapes, there is research on a display device using grass, termed artificial grass display, and its foundational element, artificial grass pixel. The artificial grass pixel employs the mechanism of pin displays and two types of grass to dynamically control the color of the grass. Moreover, studies are being conducted on the method of color scale mapping for the artificial grass pixel. However, there is a problem in experiments in the real space conditions due to the experimental overhead of acquiring a lot of data for color scale mapping. In order to solve this problem, this study aims to replicate and evaluate the artificial grass pixel in a virtual space using Computer Graphics (CG) technology. In this paper, we propose a novel method to estimate characteristic parameters of CG models based on a genetic algorithm to minimize the color difference from a real model. As a result, by performing calibration using multiple sets of real data, it was confirmed that the simulated grass pixel demonstrated color and color scale evaluation results aligned based on the color difference with the grass pixel in the real space.Item Ownership Estimation for Tracked Hands in a Colocated VR Environment(The Eurographics Association, 2023) Reimer, Dennis; Scherzer, Daniel; Kaufmann, Hannes; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtHand tracking systems play a crucial role in virtual reality (VR) applications, typically focusing on tracking the hands of the user who is using the system. Consequently, most existing systems are designed to track a maximum of two hands simultaneously. However, in certain colocated multi-user VR scenarios, it becomes necessary to track more than two hands simultaneously, such as to eliminate blind spots in individual tracking systems. In such scenarios, accurately assigning the tracked hands to the corresponding users using only the hand locations relative to the users becomes essential. This paper introduces and evaluates various methods for efficiently assigning hands to users in such scenarios. Additionally, we propose an algorithm that leverages past assignments to enhance the robustness and effectiveness of future assignments. Our experimental results demonstrate that this algorithm significantly improves upon existing methods. Furthermore, when combined with an assignment algorithm based on reinforcement learning AI agents, we achieve a remarkable 99% accuracy in hand assignments. As a result, we present an assignment algorithm specifically tailored for colocated VR scenarios, utilizing only the hand and user locations within the scene, making it directly applicable in the aforementioned contexts.Item 3D Reconstruction for Tele-Immersion in 360° Live Stream(The Eurographics Association, 2023) Dluzniewski, Clément; Chekirou, Hakim; Garrec, Jérémie Le; Andriot, Claude; Noël, Frédéric; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtNowadays, most volumetric tele-immersion systems are based on a multi-camera system to capture a dynamic 3D place. With these acquisition devices, the development of a mobile tele-immersion system seems compromised, as a lot of equipment would have to be moved. One promising way to achieve a mobile system would be to use a single 360° camera and develop ways of reconstructing in 3D a dynamic scene in real time from a single point of view. Therefore, we propose an approach to freely navigate into a 360° video captured with a static camera. The approach considers three types of elements in the scene, the environment, the object of interest and the people, and relies on a different 3D representation for each type of element. Distinguishing the scene elements enables a real-time method to be adopted, by reconstructing static elements once and using fast-computable 3D representations for dynamic elements. As the method is real-time, we develop a streaming pipeline to enable XR users to move live within the camera stream.Item Developing a Scale for Measuring the Believability of Virtual Agents(The Eurographics Association, 2023) Guo, Siqi; Adamo, Nicoletta; Mousas, Christos; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtCreating believable virtual agents has long been the focus of artists and scientists. A believable agent enables the audience to be emotionally involved in a narrative, willingly suspending their disbelief for the pleasure of appreciating literacy, drama, film, etc. In the past few decades, believability has become the goal of virtual reality developers and researchers. In the realm of virtual reality, it is commonly accepted that a believable virtual agent should have personality, emotion, agency, intelligence, and more. Despite its seemingly complicated requirements, believability is a fragile product that can be easily jeopardized by missing one or more of these elements. In this paper, we review the questionnaires that past researchers have used on the topic of virtual agents' believability. Based on the prevailing questions identified in the relevant studies, we propose a scale-aiming at standardizing one-for measuring the believability of virtual agents. We recommend that future research involving virtual agents refer to this scale to evaluate the level of their believability.Item Impact of Immersiveness on Persuasiveness, Politeness, and Social Adherence in Human-Agent Interactions within Small Groups(The Eurographics Association, 2023) Zojaji, Sahba; Steed, Anthony; Peters, Christopher; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtPoliteness is critical for shaping human-human interactions and therefore seems an important consideration in human interactions with Embodied Conversational Agents (ECAs). However, the impact of artificially-generated politeness behaviors on humans in Virtual Environments (VE) is not clear. We explore the impact of immersiveness on the perceived politeness and consequent persuasive abilities of ECAs in a small group context. A user study with two main conditions, immersive and nonimmersive, was conducted with 66 participants. In the immersive condition, participants were fully immersed in virtual reality (HMD, walking freely), while in the non-immersive condition, participants used a desktop computer interface (screen display, mouse and keyboard control). In both conditions, the primary agent in a group of two ECAs invited participants to join the group using six politeness behaviors derived from Brown and Levinson's politeness theory. While the results of the study did not indicate any significant differences between the immersive and non-immersive conditions in terms of persuasiveness and offensiveness, in the immersive condition, participants perceived the ECAs as less friendly and found their requests to be less clear. On the other hand, participants in the immersive condition reported a greater sense of freedom. Furthermore, the nonimmersive condition showed higher adherence to social norms compared to the immersive condition. These findings emphasize the significance of examining immersiveness on the persuasiveness of ECAs and their perceived politeness and social adherence by humans in human-agent interactions within small groups.