Abstract
This paper proposes an estimation method for solar radiation intensity, using pictures taken by a web camera. This approach makes use of the relationship between solar radiation intensity and the color properties of pictures. A clear day model and a cloudy day model are introduced as fourth-order polynomial expressions consisting of the brightness value and saturation as color properties. Furthermore, a hybrid model that can be switched to either the clear day model or the cloudy day model, according to the weather as determined by Japan Meteorological Agency, is developed. The validity of the proposed method is examined using the mean absolute error. Based on the study results, the proposed method can effectively measure solar radiation intensity.