Estimation of Dynamic Light Changes in Outdoor Scenes Without the use of Calibration Objects

The work presented in this paper explores how dynamical light parameters in an outdoor environment can be estimated for use in a real-time augmented reality (AR) system. A method using existing inverse rendering techniques is used to acquire diffuse surface reflectances in an offline procedure. The reflectances are used in an on-line procedure to estimate the illumination parameters of an outdoor scene. The method presented reduces the light estimation problem of outdoor scenes to a modified Phong shading model with two unknown parameters, which can be determined through the use of a linear equations system. The work presented provides an elegant method for estimating dynamically changing illumination parameters without the need for a calibration object in the scene