The recent release of the Oculus Rift, originally developed for entertainment applications, has reignited the interest of researchers and clinicians toward the use of head-mounted-displays in basic behavioral research and physical and psychological rehabilitation. However, careful evaluation of the Oculus Rift is necessary to determine whether it can be effectively used in these novel applications. In this article we address two issues concerning the perceptual quality of the Oculus Rift. (a) Is the Oculus able to generate an acceptable degree of immersivity? In particular, is it possible to elicit the sensation of presence via the virtual stimuli rendered by the device? (b) Does the Virtual Reality experienced through the Oculus Rift induce physical discomfort? To answer these questions, we employed four virtual scenarios in three separate experiments and evaluated performance with objective and subjective outcomes. In Experiment 1 we monitored observers’ heart rate and asked them to rate their Virtual Reality experience via a custom questionnaire. In Experiment 2 we monitored observers’ head movements in reaction to virtual obstacles and asked them to fill out the Simulator Sickness Questionnaire (Kennedy et al., 1993) both before and after experiencing Virtual Reality. In Experiment 3 we compared the Oculus Rift against two other low-cost devices used in immersive Virtual Reality: the Google cardboard and a standard 3DTV monitor. Observers’ heart rate increased during exposure to Virtual Reality, and they subjectively reported the experience to be immersive and realistic. We found a strong relationship between observers’ fear of heights and vertigo experienced during one of the virtual scenarios involving heights, suggesting that observers felt a strong sensation of presence within the virtual worlds. Subjects reacted to virtual obstacles by moving to avoid them, suggesting that the obstacles were perceived as real threats. Observers did not experience simulator sickness when the exposure to Virtual Reality was short and did not induce excessive amounts of vection. Compared to the other devices the Oculus Rift elicited a greater degree of immersivity. Thus our investigation suggests that the Oculus Rift head-mounted-display is a potentially powerful tool for a wide array of basic research and clinical applications.

Cybersickness is one of the major roadblocks in the widespread adoption of mixed reality devices. Prolonged exposure to these devices, especially virtual reality devices, can cause users to feel discomfort and nausea, spoiling the immersive experience. Incorporating spatial blur in stereoscopic 3D stimuli has shown to reduce cybersickness. In this paper, we develop a technique to incorporate spatial blur in VR systems inspired by the human physiological system. The technique makes use of concepts from foveated imaging and depth-of-field. The developed technique can be applied to any eye tracker equipped VR system as a post-processing step to provide an artifact-free scene. We verify the usefulness of the proposed system by conducting a user study on cybersickness evaluation. We used a custom-built rollercoaster VR environment developed in Unity and an HTC Vive Pro Eye headset to interact with the user. A Simulator Sickness Questionnaire was used to measure the induced sickness while gaze and heart rate data were recorded for quantitative analysis. The experimental analysis highlighted the aptness of our foveated depth-of-field effect in reducing cybersickness in virtual environments by reducing the sickness scores by approximately 66%.

Due to the Covid-19 pandemic, millions of people had to stay at home for several months and to move their everyday activities online. From smart-working to online learning, also considering entertainment activities, people started to extensively use platforms for remote communication and for sharing video, text, and audio content. Such systems are able to cope with the need of communicating, but the common feeling is that people, and especially students, are missing the physical relationships with classmates and colleagues. In this paper, we analyse two modalities that can be used to give an online University lecture, by focusing on the ‘sense of presence’, i.e. on the ability to produce into students the psychological sense of being in a classroom together with the teacher and their classmates. We consider a standard web-conferencing system, and a Virtual Reality social platform. We also take into account the ‘usability’ factors, to understand if extended reality systems could be, in a near future, a possible alternative to improve distance lectures and meetings.

Reaching a target object in an unknown and unstructured environment is easily performed by human beings. However, designing a humanoid robot that executes the same task requires the implementation of complex abilities, such as identifying the target in the visual field, estimating its spatial location, and precisely driving the motors of the arm to reach it. While research usually tackles the development of such abilities singularly, in this work we integrate a number of computational models into a unified framework, and demonstrate in a humanoid torso the feasibility of an integrated working representation of its peripersonal space. To achieve this goal, we propose a cognitive architecture that connects several models inspired by neural circuits of the visual, frontal and posterior parietal cortices of the brain. The outcome of the integration process is a system that allows the robot to create its internal model and its representation of the surrounding space by interacting with the environment directly, through a mutual adaptation of perception and action. The robot is eventually capable of executing a set of tasks, such as recognizing, gazing and reaching target objects, which can work separately or cooperate for supporting more structured and effective behaviors.

We have developed a low-cost, practical gaze-contingent display in which natural images are presented to the observer with dioptric blur and stereoscopic disparity that are dependent on the three-dimensional structure of natural scenes. Our system simulates a distribution of retinal blur and depth similar to that experienced in real-world viewing conditions by emmetropic observers. We implemented the system using light-field photographs taken with a plenoptic camera which supports digital refocusing anywhere in the images. We coupled this capability with an eye-tracking system and stereoscopic rendering. With this display, we examine how the time course of binocular fusion depends on depth cues from blur and stereoscopic disparity in naturalistic images. Our results show that disparity and peripheral blur interact to modify eye-movement behavior and facilitate binocular fusion, and the greatest benefit was gained by observers who struggled most to achieve fusion. Even though plenoptic images do not replicate an individual's aberrations, the results demonstrate that a naturalistic distribution of depth-dependent blur may improve 3-D virtual reality, and that interruptions of this pattern (e.g., with intraocular lenses) which flatten the distribution of retinal blur may adversely affect binocular fusion.