Abstract In this paper we propose SPaGS, a high‐quality, real‐time free‐viewpoint rendering approach from 360‐degree panoramic images. While existing methods building on Neural Radiance Fields or 3D Gaussian Splatting have difficulties to achieve real‐time frame rates and high‐quality results at the same time, SPaGS combines the advantages of an explicit 3D Gaussian‐based scene representation and ray casting‐based rendering to attain fast and accurate results. Central to our new approach is the exact calculation of axis‐aligned bounding boxes for spherical images that significantly accelerates omnidirectional ray casting of 3D Gaussians. We also present a new dataset consisting of ten real‐world scenes recorded with a drone that incorporates both calibrated 360‐degree panoramic images as well as perspective images captured simultaneously, i.e., with the same flight trajectory. Our evaluation on this new dataset as well as established benchmarks demonstrates that SPaGS excels over state‐of‐the‐art methods in terms of both rendering quality and speed.

In this paper we investigate the use of electrical muscle stimulation (EMS) to trigger eye blinks for instant hand redirection in virtual reality (VR). With the rapid development of VR technology and increasing user expectations for realistic experiences, maintaining a seamless match between real and virtual objects becomes crucial for immersive interactions. However, hand movements are fast and sometimes unpredictable, increasing the need for instantaneous redirection. We introduce EMS to the field of hand redirection in VR through precise stimulation of the eyelid muscles. By exploiting the phenomenon of change blindness through natural eye blinks, our novel stimulation model achieves instantaneous, imperceptible hand redirection without the need for eye tracking. We first empirically validate the efficiency of our EMS model in eliciting full eye closure. In a second experiment, we demonstrate the feasibility of using such a technique for seamless instantaneous displacement in VR and its particular impact for hand redirection. Among other factors, our analysis also delves into the under-explored domain of gender influence on hand redirection techniques, revealing significant gender-based performance disparities.

In this paper we propose omnidirectional galvanic vestibular stimulation (GVS) to mitigate cybersickness in virtual reality applications. One of the most accepted theories indicates that Cybersickness is caused by the visually induced impression of ego motion while physically remaining at rest. As a result of this sensory mismatch, people associate negative symptoms with VR and sometimes avoid the technology altogether. To reconcile the two contradicting sensory perceptions, we investigate GVS to stimulate the vestibular canals behind our ears with low-current electrical signals that are specifically attuned to the visually displayed camera motion. We describe how to calibrate and generate the appropriate GVS signals in real-time for pre-recorded omnidirectional videos exhibiting ego-motion in all three spatial directions. For validation, we conduct an experiment presenting real-world 360° videos shot from a moving first-person perspective in a VR head-mounted display. Our findings indicate that GVS is able to significantly reduce discomfort for cybersickness-susceptible VR users, creating a deeper and more enjoyable immersive experience for many people.

We investigate the brain’s subliminal response to fake portrait videos using electroencephalography, with a special emphasis on the viewer’s familiarity with the depicted individuals.Deepfake videos are increasingly becoming popular but, while they are entertaining, they can also pose a threat to society. These face-swapped videos merge physiognomy and behaviour of two different individuals, both strong cues used for recognizing a person. We show that this mismatch elicits different brain responses depending on the viewer’s familiarity with the merged individuals.Using EEG, we classify perceptual differences of familiar and unfamiliar people versus their face-swapped counterparts. Our results show that it is possible to discriminate fake videos from genuine ones when at least one face-swapped actor is known to the observer. Furthermore, we indicate a correlation of classification accuracy with level of personal engagement between participant and actor, as well as with the participant’s familiarity with the used dataset.

Abstract The peak of virtual reality offers new exciting possibilities for the creation of media content but also poses new challenges. Some areas of interest might be overlooked because the visual content fills up a large portion of viewers' visual field. Moreover, this content is available in 360° around the viewer, yielding locations completely out of sight, making, for example, recall or storytelling in cinematic Virtual Reality (VR) quite difficult. In this paper, we present an evaluation of Stereo Inverse Brightness Modulation for effective and subtle guidance of participants' attention while navigating dynamic virtual environments. The used technique exploits the binocular rivalry effect from human stereo vision and was previously shown to be effective in static environments. Moreover, we propose an extension of the method for successful guidance towards target locations outside the initial visual field. We conduct three perceptual studies, using 13 distinct panorama videos and two VR systems (a VR head mounted display and a fully immersive dome projection system), to investigate (1) general applicability to dynamic environments, (2) stimulus parameter and VR system influence, and (3) effectiveness of the proposed extension for out‐of‐sight targets. Our results prove the applicability of the method to dynamic environments while maintaining its unobtrusive appearance.

Abstract This article investigates neural and physiological correlates of simulator sickness (SS) through a controlled experiment conducted within a fully immersive dome projection system. Our goal is to establish a reliable, objective, and in situ measurable predictive indicator of SS. SS is a problem common to all types of visual simulators consisting of motion sickness‐like symptoms that may be experienced while and after being exposed to a dynamic, immersive visualization. It leads to ethical concerns and impaired validity of simulator‐based research. Due to the popularity of virtual reality devices, the number of people exposed to this problem is increasing and, therefore, it is crucial to find reliable predictors of this condition before any symptoms appear. Despite its relevance and the several theories about its origins, SS cannot yet be quantitatively modeled and predicted. Our results indicate that, while neural correlates did not materialize, physiological measures may be a solid early indicator of oncoming SS.

In this paper, we propose a new method for attention and gaze redirection, specifically designed for immersive stereo displays. Exploiting the dual nature of stereo imagery, our stimulus is composed of complementary parts displayed for each individual eye. This attracts viewers’ attention due to induced binocular rivalry. In a perceptual study, we investigate size- and intensity-related perceptual thresholds of our stimulus for six different real-world panorama images. Our results show that a flexible parameterization allows the stimulus to be perceived even in complex surroundings. To prepare for technical innovations expected in future-generation virtual reality headsets, we used a commercially available head-mounted display as well as a high-resolution dps.

We present the ICG Dome, a research facility to explore human visual perception in a high-resolution virtual environment. Current state-of-the-art VR devices still suffer from some technical limitations, like limited field of view, screen-door effect or so-called god-rays. These issues are not present or at least strongly reduced in our system, by design. Latest technology for real-time motion capture and eye tracking open up a wide range of applications.

We investigate the feasibility of combining off-the-shelf virtual reality headsets and electroencephalography. EEG is a highly sensitive tool and subject to strong distortions when exerting physical force like mounting a VR headset on top of it that twists sensors and cables. Our study compares the signal quality of EEG in VR against immersive dome environments and traditional displays using an oddball paradigm experimental design. Furthermore, we compare the signal quality of EEG when combined with a commodity VR headset without modification against a modified version that reduces physical strain on the EEG headset. Our results indicate, that it is possible to combine EEG and VR even without modification under certain conditions. VR headset customisation improves signal quality results. Additionally, display latency of the different modalities is visible on a neurological level.

No abstract available.

In a concurrent electroencephalography (EEG) and eye-tracking study, we explore the specific neural responses associated with saccadic eye movements. We hypothesise that there is a distinct saccade-related neural response that occurs well before a physical saccade and that this response is different for free, natural saccades versus forced saccades. Our results show a distinct and measurable brain response approximately 200 ms before a physical saccade actually occurs. This response is distinctly different for free saccades versus forced saccades. Our results open up possibilities of predicting saccades based on neural data. This is of particular relevance for creating effective gaze guidance mechanisms within a virtual reality (VR) environment and for creating faster brain computer interfaces (BCI).

In this article, we evaluate various image-space modulation techniques that aim to unobtrusively guide viewers’ attention. While previous evaluations mainly target desktop settings, we examine their applicability to ultrawide field of view immersive environments, featuring technical characteristics expected for future-generation head-mounted displays. A custom-built, high-resolution immersive dome environment with high-precision eye tracking is used in our experiments. We investigate gaze guidance success rates and unobtrusiveness of five different techniques. Our results show promising guiding performance for four of the tested methods. With regard to unobtrusiveness we find that—while no method remains completely unnoticed—many participants do not report any distractions. The evaluated methods show promise to guide users’ attention also in a wide field of virtual environment applications, e.g., virtually guided tours or field operation training.

There is a continuous effort by animation experts to create increasingly realistic and more human-like digital characters. However, as virtual characters become more human they risk evoking a sense of unease in their audience. This sensation, called the Uncanny Valley effect, is widely acknowledged both in the popular media and scientific research but empirical evidence for the hypothesis has remained inconsistent. In this paper, we investigate the neural responses to computer-generated faces in a cognitive neuroscience study. We record brain activity from participants (N = 40)} using electroencephalography (EEG) while they watch videos of real humans and computer-generated virtual characters. Our results show distinct differences in neural responses for highly realistic computer-generated faces such as Digital Emily compared with real humans. These differences are unique only to agents that are highly photorealistic, i.e. the `uncanny' response. Based on these specific neural correlates we train a support vector machine~(SVM) to measure the probability of an uncanny response for any given computer-generated character from EEG data. This allows the ordering of animated characters based on their level of `uncanniness'.

This study compares three popular modalities for analyzing perceived video quality; user ratings, eye tracking, and EEG. We contrast these three modalities for a given video sequence to determine if there is a gap between what humans consciously see and what we implicitly perceive . Participants are shown a video sequence with different artifacts appearing at specific distances in their field of vision; near foveal, middle peripheral, and far peripheral. Our results show distinct differences between what we saccade to (eye tracking), how we consciously rate video quality, and our neural responses (EEG data). Our findings indicate that the measurement of perceived quality depends on the specific modality used.