• Visual Comfort in Transitional Spaces

      Araji, Mohamad Tarek; Chalfoun, Nader; Jeffery, R. Brooks; Jabbour, Ghassan (The University of Arizona., 2004)
      The study emphasizes changing light conditions in architectural spaces as a major factor on human eye adaptation, which represents a potential case for a visual shock. This visual shock is experienced when occupants encounter a sudden field of light whose intensity is above or below the limit of human eye adaptable range. To examine this condition, a new methodology is developed and outlined. It identifies the visual shock within transitional spaces and allows architects to investigate strategies that influence visual comfort. The physiological field of vision analysis is used to first critique, then to adjust, and finally to interpret scenes within transitional spaces. The methodology begins by using a 180° angle fish-eye lens camera to capture 3-D photographs along a selected pedestrian pathway. The photographs are overlaid by a “field of view” diagram to deduct areas obstructed by human facial features (eyebrows, cheeks, and nose). Area weighted percentages of the net view profile is then calculated using an overlay hemispherical radial grid. These percentages represent the cut-off vision (0%), the one-eye vision (12.5%), the peripheral vision (25%), and the central vision (50%). Image metamorphosis is done by the aid of the Adobe Photoshop software to restrict the image to four monochromatic contrasts of shade. Parallel to photographs, actual light intensity readings are collected and calibrated to each assigned contrast on the images. To illustrate the methodology, a case of a person experiencing an extreme discomfort by walking in the direction of a blinding sunlight source has been chosen and investigated. 3-D Computer modeling is then adopted to investigate the different architectural daylight solutions as suggested by the modified design and predicts a visual comfort. This method provides a successful tool for investigating light in transitional spaces as well as contributes to enhancing pedestrian awareness of their surrounding environment and clarity of visual information.