Surface texture and microstructure extraction from multiple aerial images

Textures and microstructures on the surfaces of cultural objects, such as b uildings and parking lots, provide important information for many military and civilian applications. The extraction of this information from aerial i magery is difficult due to problems arising from perspective distortion, da ta deficiency, and corruption caused by shadows and occlusions. In this pap er we present a generic surface texture and microstructure extraction syste m to deal with these problems, under the assumption that an initial 3-D geo metric site model is given and sufficient camera and light source informati on is known. The infrastructure of the system is an orthographic facet imag e library that systematically collects surface intensities from multiple ae rial images into a database, eliminates the effects of shadows and occlusio ns, and forms a complete and consistent surface intensity representation. A robust, local intensity based image analysis module is designed to symboli cally extract surface microstructures with rectilinear and repetitive patte rns. The paper shows successful applications of the system to extractions o f both 2-D and 3-D microstructures. The system is typically useful for urba n site model refinement and visualization. (C) 2001 Academic Press.