Photogrammetry
Deriving 3D geometry and point clouds from overlapping photographs.
Photogrammetry is a reality-capture technique that derives 3D models or measurements from multiple overlapping photographs, analysing them to reconstruct geometry and texture — producing a point cloud and/or a mesh.
It needs generous overlap between images — typically 60–80%. Structure-from-Motion software finds common points across the photos and triangulates their 3D positions, assigning each pixel an X, Y, Z coordinate while correcting lens distortion and georeferencing the result. The images are often captured by drone (UAV) to cover large areas from many angles.
Against laser scanning, the trade-offs reverse: photogrammetry excels at realistic colour and texture and is cheaper and faster over large areas, but is less metrically precise, where laser scanning prioritises accuracy. Both produce point clouds as the basis for parametric modelling, and both feed scan-to-BIM — photogrammetry especially for external or less intricate surveys. In Italian it is fotogrammetria.
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