Abstract
It is indispensable to understand the adaptation luminance which provides for the visual sensitivity when the visibility is discussed. For the visual field with uniform luminance distribution, the luminance of the visual field becomes the adaptation luminance. On the other hand, for the visual field with complex luminance distribution, the determination method of adaptation luminance from the luminance distribution of the visual field has not been established yet. In this research, it was tried to determine the adaptation luminance for the visual field with complex luminance distribution by the following process. First, we specified the conditions of a visual object which became a visual threshold in the actual space. And next, we found the luminance of the visual field on which a visual object with the same conditions became the visual threshold in the visual field with uniform luminance distribution.
