Radiometric calibration with consideration of the linear CCD signal model

Abstract

iWe present a framework for estimating the RGB and rg values of an image using a linear CCD signal model and the camera response function. The RGB response functions of an Olympus Stylus 770 SW digital camera were derived using the Devebec-Malik algorithm, which makes use of differently exposed images to map relative irradiance. Obtained average color differences ranged from 17.7±15.0% to 64.7±9.6% and 4.1±15.0% to 8.2±5.8% for RGB and rg, respectively over the exposure time range of 1/640 s 1/250 s for CDD scaling factors k = 5.0, 8.0, and 15.0. The minimum average color difference was also found to shift from high-to-low exposure values as k was increased from k = 5 to k = 15, suggesting that there is an ideal scaling factor k for a particular exposure time range. Moreover, obtained color differences assert the robustness of rg estimates under possible illumination-varying conditions.