This report is about visual performance of human face under LED crime prevention lighting in outdoor space or large room whose interior is black. Subjects evaluate observed person who leaves 5m from a crime prevention lighting, and all experimental conditions is without silhouette phenomenon. In the case of outdoor space number of subjects is 19, and In the case of dark room is 23. Because every lighting occurs low glare, visibility strongly correlates with discomfort glare. Regardless of observation position, the higher lighting source luminance is, the higher visibility is. It means that disability glare can't exceed increasing visibility with increasing luminance of a visual object. It is noted about luminance index of visibility that method of luminance measurement remains some problem. Furthermore, the higher correlated colour temperature is, the lower visibility is slightly. However when observation position is far, there is no influence of correlated colour temperature on visibility. Finally this report refers about some problems by blue LED crime prevention lighting.
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