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In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user’s hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects). After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP) components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning. [ABSTRACT FROM AUTHOR]

Stereoscopic 3-D visualization (S3D) provides a user with higher comprehension of remote environments in teleoperation when compared to 2-D viewing. Studies in the literature have shown how stereo vision may contribute to improving perception of some depth cues, but it is hard to find work assessing stereoscopic 3-D viewing in telenavigation tasks involving medical flexible endoscopes. Nonetheless, the increased level of depth awareness provided by stereo viewing is remarkable, which facilitates endoscope teleguide, teleexploration, and teleintervention, leading to accurate navigation and faster decision-making. This paper assesses S3D in medical endoscopic teleoperation. We evaluate the usability of a flexible stereoscopic bronchoscope. Twenty test users are asked to teleguide a virtual endoscope, which operates in a realistically simulated bronchus environment under different viewing conditions and displays. The evaluation involves seven systems (from laptops to wall screen and head-mounted display), four approaches to stereo viewing (colored Anaglyph, polarized filters, shutter glasses, and separated displays), and five types of display technologies (digital light processing, cathode ray tube, liquid crystal display, light-emitting diode (LED), and organic LED). The results show a strong improvement in users' performance when the endoscope-camera view is (depth-) enhanced by stereo viewing. Users' performance and appreciation may vary in different systems, which is also commented in this paper. This study supports system designers in making informed decisions. [ABSTRACT FROM PUBLISHER]

Performance improvements in graphics hardware have made it possible to visualize complex virtual environments and provided opportunities to interact with these in a more realistic way. In this paper two different types of Virtual Reality applications for simulating a billiards game are presented. In one application a commercial haptic interface is used to provide a force feedback, thus rendering the interaction realistic and exciting to the user. However, there are limitations due to the use of a commercial haptic device which has not been specifically designed for this game and thus limits the workspace. Also, in the commercial device, it is not possible to use the left hand when aiming and striking the ball, as you can in a real game of billiards. In order to overcome these limitations another type of simulation has been developed using a real billiard cue; its movements are reproduced in the virtual environment using a visual marker detection system. No force feedback is provided to the player. In the game simulations the virtual environments have been built using the development environment XVR in the first simulator and OpenSceneGraph in the second; rigid body dynamics have been simulated utilizing the ODE and PhysX physics engines. ARToolkit was the visual marker-based detection system utilized to replicate the movements of the real cue used by the player in the virtual environment of the second simulator. [ABSTRACT FROM AUTHOR]

The aim of this work is to develop a realistic virtual model of the human brain that could be used in a neurosurgical simulation for both educational and preoperative planning purposes. The goal of such a system would be to enhance the practice of surgery students, avoiding the use of animals, cadavers and plastic phantoms. A surgeon, before carrying out the real procedure, will, with this system, be able to rehearse by using a surgical simulator based on detailed virtual reality models of the human brain, reconstructed with real patient's medical images. In order to obtain a realistic and useful simulation we focused our research on the physical modelling of the brain as a deformable body and on the interactions with surgical instruments. The developed prototype is based on the mass-spring-damper model and, in order to obtain deformations similar to the real ones, a three tiered structure has been built. In this way, we have obtained local and realistic deformations using an ad-hoc point distribution in the volume where the contact between the brain surface and a surgical instrument takes place. [ABSTRACT FROM AUTHOR]

The developed system is the first prototype of a virtual interface designed to avoid contact with the computer so that the surgeon is able to visualize 3D models of the patient's organs more effectively during surgical procedure or to use this in the pre-operative planning. The doctor will be able to rotate, to translate and to zoom in on 3D models of the patient's organs simply by moving his finger in free space; in addition, it is possible to choose to visualize all of the organs or only some of them. All of the interactions with the models happen in real-time using the virtual interface which appears as a touch-screen suspended in free space in a position chosen by the user when the application is started up. Finger movements are detected by means of an optical tracking system and are used to simulate touch with the interface and to interact by pressing the buttons present on the virtual screen. [ABSTRACT FROM AUTHOR]