Obtaining Absolute Scene Luminance Using HDR Imaging

The absolute measure of scene luminance is needed in many applications, e.g., color image reproduction (especially outdoor), surveillance images, light appearance, and glare prediction. Currently, commercial luminance cameras are being used, which are very expensive and have limitations in dynamic range. An efficient and inexpensive method is needed to obtain absolute luminance of each of pixels in the scene. In the current study, a method was proposed to obtain absolute scene luminance (XYZ map) at each pixel using digital RGB camera and high dynamic range (HDR) imaging. The proposed model was calibrated using a tele-spectroradiometer (TSR) by means of average luminance at a small spot. A good match of results was obtained between TSR and the proposed method.