Abstract
This study aims to reveal how, depending on the horizontal distance, a sense of perspective is created based on the roughness of the luminance variation in an image. More specifically, we attempt to determine what sizes of the luminance variations in the light and dark portions of a building, when it is observed from a horizontal distance, in comparison to the sizes of the light and dark portions of the facade components, make it easy for viewers to discern a sense of perspective for the facade components. We carried out an experiment by using a 1/50 scale model of this building. In the experiment, subjects were placed in a darkroom, and the model was lit up using optical fibers that were illuminated by halogen lamps. The items evaluated were the discernment of a sense of perspective for four facade components: the column, capital ornament, wall surface, and opening periphery. As the results are following; (1) The result of the filtering analysis revealed that the sizes of the light and dark portions on the facade surface with the maximal luminance ratio are determined by the size of the facade component and the illumination method. (2) The observed sizes of the light and dark portions with the maximal luminance ratio, for which the highest evaluation was obtained, change mainly with the component size. A sense of perspective can be easily created at a size of 0.5-2.0deg (0.5-1deg in the vertical direction of a column capital and horizontal lattice and 1.5-2deg in the horizontal direction of a cylinder.) (3) In the evaluation of the sense of perspective for the facade components of a lit-up building, it appears effective to use the observed size of the light and dark portions with the maximal luminance ratio observed when a viewer looks at an object from a horizontal distance.
