Browsing by Author "Marchal, Maud"

Now showing 1 - 3 of 3
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    Detailed Eye Region Capture and Animation
    (The Eurographics Association and John Wiley & Sons Ltd., 2022) Kerbiriou, Glenn; Marchal, Maud; Avril, Quentin; Dominik L. Michels; Soeren Pirk
    Even if the appearance and geometry of the human eye have been extensively studied during the last decade, the geometrical correlation between gaze direction, eyelids aperture and eyelids shape has not been empirically modeled. In this paper, we propose a data-driven approach for capturing and modeling the subtle features of the human eye region, such as the inner eye corner and the skin bulging effect due to globe orientation. Our approach consists of an original experimental setup to capture the eye region geometry variations combined with a 3D reconstruction method. Regarding the eye region capture, we scanned 55 participants doing 36 eyes poses. To animate a participant's eye region, we register the different poses to a vertex wise correspondence before blending them in a trilinear fashion. We show that our 3D animation results are visually pleasant and realistic while bringing novel eye features compared to state of the art models.
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    Does the Control Law Matter? Characterization and Evaluation of Control Laws for Virtual Steering Navigation
    (The Eurographics Association, 2020) Brument, Hugo; Olivier, Anne-Hélène; Marchal, Maud; Argelaguet, Ferran; Argelaguet, Ferran and McMahan, Ryan and Sugimoto, Maki
    This paper aims to investigate the influence of the control law in virtual steering techniques, and in particular the speed update, on users' behaviour while navigating in virtual environments. To this end, we first propose to characterize existing control laws. Then, we designed a user study to evaluate the impact of the control law on users' behaviour and performance in a navigation task. Participants had to perform a virtual slalom while wearing a head-mounted display. They were following three different sinusoidal-like trajectory (with low, medium and high curvature) using a torso-steering navigation technique with three different control laws (constant, linear and adaptive). The adaptive control law, based on the biomechanics of human walking, takes into account the relation between speed and curvature. We propose a spatial and temporal analysis of the trajectories performed both in the virtual and the real environment. The results show that users' trajectories and behaviors were significantly affected by the shape of the trajectory but also by the control law. In particular, users' angular velocity was higher with constant and linear laws compared to the adaptive law. The analysis of subjective feedback suggests that these differences might result in a lower perceived physical demand and effort for the adaptive control law. The paper concludes discussing the potential applications of such results to improve the design and evaluation of navigation control laws.
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    Electrotactile Feedback For Enhancing Contact Information in Virtual Reality -- Best Paper Award
    (The Eurographics Association, 2021) Vizcay, Sebastian; Kourtesis, Panagiotis; Argelaguet, Ferran; Pacchierotti, Claudio; Marchal, Maud; Orlosky, Jason and Reiners, Dirk and Weyers, Benjamin
    This paper presents a wearable electrotactile feedback system to enhance contact information for mid-air interactions with virtual objects. In particular, we propose the use of electrotactile feedback to render the interpenetration distance between the user's finger and the virtual content is touched. Our approach consists of modulating the perceived intensity (frequency and pulse width modulation) of the electrotactile stimuli according to the registered interpenetration distance. In a user study (N=21), we assessed the performance of four different interpenetration feedback approaches: electrotactile-only, visual-only, electrotactile and visual, and no interpenetration feedback. First, the results showed that contact precision and accuracy were significantly improved when using interpenetration feedback. Second, and more interestingly, there were no significant differences between visual and electrotactile feedback when the calibration was optimized and the user was familiarized with electrotactile feedback. Taken together, these results suggest that electrotactile feedback could be an efficient replacement of visual feedback for enhancing contact information in virtual reality avoiding the need of active visual focus and the rendering of additional visual artefacts.