Abstract:

Occlusion detection is a critical step in the true orthophoto procession. According to the principle of Ray-tracing occlusion detection, TIN data are divided into the base triangular network and wall triangular network which are processed separately, for grid data the variation of elevation difference between the ray and DSM is used to determine occlusion relationship, thereby obtaining improved occlusion detection algorithms. Experiments show that the algorithms can precisely detect occlusion area of complex buildings. Especially the grid-based Ray-tracing occlusion detection is more simple and effective.

Key words: true orthophoto, occlusion detection, ray-tracing, TIN