HDR luminance measurement: Comparing real and simulated data
Authors: Au, Peony; Donn, Michael
This research explores the adequacy of simulation using HDR images to map the luminance distribution both of the sky and of the building interiors. Currently the BRANZ Building Energy End-Use Study (BEES) team have one internal lighting measurement point recording light levels in each of more than 100 randomly selected commercial buildings in New Zealand. The light meter typically records illuminance on a desktop within the building every five minutes for a minimum of two weeks. Using that data, this thesis will explore the utility of HDR imaging as a supplement to this single internal light measurement in the analysis of daylight potential in New Zealand commercial buildings.
This research begins with physical models and HDR imaging in the artificial sky in the lighting laboratory at the School of Architecture, Victoria University of Wellington. It is further developed further in a randomly selected building from the BEES study. The model, the artificial (cloudy) sky and the real building are evaluated in a daylight simulation program. Part of the exercise is to determine the adequacy of a Smartphone HDR application in the process, using a US $50 fisheye lens and contracting the results with a standard fisheye SLR lens.
This paper provides the preliminary results of the research in determining the adequacy of one internal lighting measurement as a means of assessing daylight performance of a building.