This article reports one task of a global investigation based on a comprehensive day lighting system designed for refurbished and new buildings. This study epitomizes the research conducted by a French group working on green energy. The authors aim to provide occupants with daylight for everyday tasks, hence reducing electricity consumption and concomitantly increasing comfort level. This article presents the conception and design of a new virtual sensor based on a fisheye video camera devised to assess visual comfort. This device includes a fuzzy logic algorithm to handle the subjective aspect of the human perception related to sight.