STUDY ON VISIBILITY THRESHOLD CURVE OF CIRCULAR OBJECTS AND VISIBILITY ESTIMATION METHOD USING C-A GRAPH (PO25, 892-901)

It is vitally important to estimate visibility in order to maintain a visual safety especially for low-vision people. Authors have agreed that it is reasonable to establish a method to estimate visibility of objects using luminance images, and proposed C-A graph (Nakamura et al. 2016) based on contrast profile method (Nakamura et al. 2003). C-A graph presents luminance contrast and logarithmic average on vertical and horizontal axes for varying object sizes respectively. In this study, two experiments were conducted in order to consider visibility estimation method using C-A graph. The first experiment was conducted to obtain visibility threshold conditions and the second experiment was conducted to examine the relationship between visibility threshold values and visibility evaluation.