Towards automatic reconstruction of visually realistic models of buildings

This paper describes an innovation in the field of texture creation for the construction of Visually Realistic Models (VRMs) of buildings in urban areas. The development of an Automatic Texture Processing Tool (ATPT) is described which uses registered CCD images, captured in a special manner, and a Numerical Frame of Reference (NFR) to create textures of individual faces of buildings. The images are acquired on a virtual sphere using a CCD camera which is mounted on a servo-driven theodolite and are indexed using the angular readings from the theodolite. The registration of the images includes the calibration of the data capture unit and the localisation of the imaging stations. In order to process the textures, the coordinates of building faces, extracted from the NFR, are passed to the ATPT. The ATPT finds the corre-sponding images covering each face and forms the textures by extracting, rectifying, and mosaicing the image portions automatically. The system not only enables the automatic creation of textures, but also allows one to make highly accurate measurements on the resulting VRM, a task which is not possible using conventional texture processing systems. Textures of a specific face can easily be merged in order to obtain an occlusion-free or higher quality texture. Moreover, independently formed NFRs can be used to initialise the texture creation process.