Illuminance Analysis from High Dynamic Range Images

Abstract

High dynamic range (HDR) imaging offers the potential to use cameras as luminance meters. Therefore, they may also be used as illuminance meters. The luminance maps obtained from HDR photography can be analyzed according to objects, figures, ground, visual tasks, colors and luminance. The corresponding illuminance contributed by each feature can be calculated. This allows a new way of illuminance analysis: measuring the quantity of light due to specific objects, colors and features. This paper explains how to properly analyze the illuminance contributions from luminance maps. It shows an example based on an historic landmark, the State Capitol in Harrisburg, Pennsylvania.

Keywords:

• Illuminance
• digital cameras
• dynamic range
• calibration