Integrating Photogrammetry and Image Analysis for Shadow Detection
基于DSM阴影仿真和高度场光线跟踪的影像阴影检测

A mathematical model of shadow detection is introduced in this paper. It first computes the coordinates of the shadow through a photogrammetric approach. Digital surface model (DSM) and the altitude of the sun are used to detect the space coordinate of the shadow, and camera model is used to calculate the scanning line and the associated camera position for each shadow cell. Height field ray tracing is carried out to determine the visibility of each shadow. For a visible shadow, the coordinate in the projecting image is calculated. Based on this result, we extract successfully the fine segments of shadows in the image.