High dynamic range (HDR) photography is a useful luminance measurement tool but relies on the camera and lens used and photometric calibration for its accuracy, yet these aspects lack technical guidance. This study used a Canon 350D camera fitted with a Sigma 10—20 mm lens to record the luminance data of 54 grey and 18 colour targets plus a light source in a windowless classroom lit by fluorescent lighting. Six apertures (f/4—f/22), three focal lengths (10, 14, 20 mm), two ambient light levels and four ranges of exposure values were used for generating 128 HDR images in Photosphere. After vignetting correction and physical calibration, these HDR images were compared with each other for the quality of luminance acquisition. This study could benefit future HDR imaging by ensuring higher image quality.

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This study tested the appropriateness of unified glare rating (UGR), CIE glare index (CGI), British glare index (BGI), and visual comfort probability (VCP) for evaluating discomfort glare from common non-uniform electric light sources. An experiment was conducted in a windowless room. High dynamic range photogrammetry was used for measuring three non-uniform fluorescent glare sources. The luminance and geometry data were acquired to calculate the glare ratings. The sub-divisibility and additivity of UGR, CGI, BGI, and VCP were tested via numerical method. Their predictability was evaluated using 67 subjects in two sessions. It was found that UGR, CGI, BGI, and VCP all have valid additivity, but only UGR and CGI have valid sub-divisibility. Current formulae of UGR, CGI, BGI and VCP all overestimate the glare sensation from non-uniform sources that young people may feel.

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