3d photogrammetry application for building inspection of cultural heritage objects

Landmarked buildings require periodic inspection and restoration. Numerous techniques are known that allow engineers to perform detailed inspection of buildings and structures. In recent decades, 3D scanning and photogrammetry application for building inspection spread around. The purpose of the study is to develop the most effective approach to aerial photography with the use of UAV to create precise model of the building. Methodology. The technique is based on the creation of three-dimensional model out of 2-dimensional photographs with the help of dedicated software. Scientific novelty can be considered as the development of an algorithm for programming the UAV flight along the most optimal trajectory in order to obtain a sufficient number of images, and consequently constructing a model with the least number of distorted sections. The result of the work is a three-dimensional model of a building or structure with all actual sizes and textures preserved. Obtained model can be later used for a detailed study of the damages of the existing structural and architectural elements of building; also, it can be used as a background model for the reconstruction or restoration project design, depending on the research objectives. The practical significance of this method is demonstrated by the inspection of the actual landmarked building: the Mennonite school in Zaporizhia city. The inspected building was built in the late nineteenth century and has not changed its functional purpose until today. The building is one of the few well-preserved examples of authentic Mennonite architecture in the region, therefore a great deal of attention was paid for inspection and elaboration the measures for its restoration. A complex inspection was performed using 3D photogrammetric survey and creation of a three-dimensional model. Using the model, the places that need to be restored are precisely identified, and the defects that need to be eliminated are identified. The technical condition of the structures is estimated even in hard-to-reach places. Thus, it is clearly shown that the presented inspection technique significantly reduces labor intensity and raises the efficiency of building and structures inspection.