Establishment of a computer-controlled retroreflection measurement system at the National Metrology Institute of Turkey (UME)

Abstract

In order to characterize photometric properties of retroreflectors, a fully automated retroreflector measurement system is designed in National Metrology Institute of Turkey (UME). The system is composed of a lighting projector, a goniometer, filter radiometers, 100dB transimpedance amplifiers, and 24-bit resolution analog-digital converter card with a special software. The established system provides a new calibration capability to determine the luminous intensity and retroreflection coefficients of the retroreflective materials with the expanded uncertainties of 1.07% and 1.13% (k=2), respectively. The traceability in retroreflection measurements was linked to the detector-based photometric scale of UME.

New traceability chains in the photometric and radiometric measurements at the National Metrology Institute of Turkey

“…Each aperture is placed individually in front of the retroreflection device and the reflection area is defined. Then retroreflection coefficient is obtained by dividing the measured luminous intensity coefficient with the reflected area [16].…”

“…In order to measure luminous intensity and retroreflection coefficients of retroreflectors with an expanded uncertainty of 1.1% (k ¼ 2), a fully automated retroreflection measurement system has been designed at UME [16]. The system is composed of a lighting projector consisting of achromatic lens combinations capable of sending the collimated beam up to 30 m with a lighting uniformity of 0.39%, a motorized 2D goniometer system (having rotational capacities up to 7901 in both axes (b 2 ¼ AE901, b 1 ¼ AE901) with an angular resolution of 0.0011) and two filter radiometers.…”