A 3D Lighting System for fMRI Rendering Fidelity Experiments

Abstract

Although improvements in basic computer graphics rendering hardware and lighting algorithms have produced some remarkable results, it is still computationally demanding to render a highly realistic Virtual Environment (VE) in real-time. This paper presents a real-time synthetic lighting system incorporating sophisticated global illumination algorithms aiming to induce similar subjective lighting impressions as in the real world. The lighting system proposed is designed to render an interactive VE on an fMRI display, enabling the conduct of formal neuroscientific experiments and investigating the effects of visual fidelity as well as varied lighting configurations on feelings of presence, 'reality' and comfort. Ultimately, the goal is to use this system to explore the effect of lighting variations (daylight vs. forms of artificial light) on subjective impressions of a group of patients suffering from the 'depersonalization' syndrome. The system was developed in close collaboration with the Brighton and Sussex Medical School in the UK. It was a challenge to develop an interactive lighting system to be utilized for fMRI experimentation due to infrastructural and technical demands. Such demands were based on acquiring user input when immersed in the constrained environment of an fMRI scanner while the system reacts to it in real-time. fMRI experiments usually employ simple display material, for example using photographs, video clips or simple computerized stimuli. Employing VEs in fMRI has the advantage that it is possible to involve participants in interactive animated environments which more realistically reflect social and emotional situations.

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“…A lighting system has been designed to render an interactive VE on an fMRI display, enabling the conduct of formal neuroscientific experiments and investigating the effects of visual fidelity as well as varied lighting configurations of an indoors/outdoors space on feelings of presence, 'reality' and comfort [1]. A 3d virtual system for fMRI has been designed investigating the influence of two prominent VR parameters, e.g.…”