Approximate field measurement of surface luminance using a digital camera

Abstract

This paper describes a method of estimating and recording surface luminance using widely available types of digital cameras and photographic image processing software. The method involves recording the luminance of a 10-step grey scale placed within a scene at the time an image is captured. The relationship between luminosity (a value obtainable from the software) and luminance of the grey scale may then be used to determine the luminance of surfaces within the scene to an accuracy of within 10%. The technique has been successfully applied to interior and exterior scenes lit in a variety of ways and to a number of types of digital camera. The methodology, robustness and limitations of the technique are set out. © 2000, SAGE Publications. All rights reserved.