Measuring the luminance of a retroreflective sign

摘要

The area of retroreflective signage for traffic control is moving from fixed retroreflective requirements to a traffic scenario/performance based system. CIE Technical Report 54.2, "Retroreflection: Definition and Measurement", published in 2001, offers several methods for measuring the coefficient of retro reflected luminance. In this experiment, two CIE 54.2 methods, The Ratio Method and The Direct Luminance Method, along with a new method, Total Luminous Flux Method, are compared in the laboratory and through uncertainty analysis. The results show the Total Luminous Flux method has the potential for the lowest measurement uncertainty and implementation of the Direct Luminance method is not trivial showing errors as large as 20 % are easily possible.