The area of retroreflective signage for traffic control is moving from fixed retroreflective requirements to performance based systems which will require a tremendous amount of data collection. NIST has developed an imaging based system that simultaneously collects a complete dataset of coefficients of retroreflected luminance for a given entrance angle and orientation angle. These measurements are compared to a point-by-point method of collection through the calculation of the fractional retroreflectance. The advantages include the time required to collect a large number of data points. Over a million data points can be collected in one minute compared to an the collection of a little over a thousand data points, which is an incomplete sampling of the retroreflected rho angle and observation angle space, in over two hours. The fast measurement of the large number of points allows for a smaller uncertainty for the determination of parameters such as fractional retroreflectance and observation angularity. In addition, the realization of a scenario or performance based highway signage system is economically possible.
Retroreflection measurements using an imaging photometer
2008
6 Seiten, 10 Bilder, 4 Tabellen, 3 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
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