An Assessment of High Dynamic Range Luminance Measurements with LED Lighting

Abstract

This study investigates whether high dynamic range imaging (HDRI) can accurately capture luminance of a single light emitting diode (LED) chip within the luminaire. Two conventional methods of determining luminance—the use of a luminance meter with a close-up lens and deriving luminance from illuminance measurements, source area, and distance—of a single LED chip are compared to HDRI measurements. The results show that HDRI using a Canon EOS 7D camera, fitted with 28–105 mm lens and a neutral density filter (with less than 1% transmittance) combined in Photosphere compares very well to a luminance value determined with goniophotometer measurements and calculations. It provides confidence in the ability of HDRI to capture luminance of a single LED chip.

• HDRI
• LED
• luminance
• measurement

ACKNOWLEDGMENTS

We thank GE Lighting for providing LED luminaires for this research, in particular Jason Brown for all of his assistance. We also thank participants of the HDRI forum for their help, especially Greg Ward. We appreciate the support of the Charles W. Durham School of Architectural Engineering and Construction, University of Nebraska–Lincoln, and Dr. Michelle Eble-Hankins for editorial assistance.