In order to assess the characteristics of luminance distribution in diverse visual environments, the authors measured luminance distribution in a wide variety of visual environments. At first we focused attention on the strength of these luminance variations, but we were not able satisfactorily to express qualitative differences among visual environments in this way. Next, therefore, we focused on positioning that gave rise to strong luminance variations, and we were thus able to express the characteristics of luminance variations in terms of the degree of fineness which could be detected in those luminance variations. It thus became apparent that it is possible to express in this way the characteristics of luminance distribution within the visual environment.
