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.