This paper reports one task of a global investigation based on a whole daylighting system designed to equip refurbished and new buildings. This study forms part of the research conducted by a French group that works on green energy. The authors aim to provide occupants with daylight for everyday tasks, hence reducing electricity consumption and increasing comfort level as well. This paper presents the conception and design of a new virtual sensor based on a fisheye video camera dedicated to the assessment of optic comfort. This device includes a fuzzy logic kernel to deal with the subjective aspect of the human perception related to sight.