LI Yan1, GONG Peng2. Integrating Photogrammetry and Image Analysis for Shadow Detection[J]. Journal of Remote Sensing, 2005, (4): 357-362. DOI: 10.11834/jrs.20050452.
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.