Brightness of a Space in Terms of Variation of Luminance

We assume that when people look around an entire space, the total impression is created through the accumulation of visual information in every direction. We define "brightness of a space" and examine the impact factors and quantification. The results of previous studies suggest that it is reasonable to use average luminance and luminance contrast. However, when the entire space is defined as "brightness of a space", luminance contrast cannot be applied. For this reason, we consider the physical quantity that shows the variation of the brightness in our evaluation experiment on Brightness. It is possible to propose using a prediction equation of " brightness of a space" using the standard deviation of the logarithm of the luminance values and average luminance.