Recovery of object positions and shape from photographs with overlapping views. Known or estimated camera geometry and matched image features constrain three-dimensional point positions. A metric reconstruction requires scale and a coordinate reference; image pixel size is not automatically the positional accuracy of the reconstructed surface. Stereo photogrammetry and structure-from-motion photogrammetry use related geometry with different acquisition and camera-estimation strategies.
An identifiable image feature or target with independently surveyed coordinates, used to georeference and constrain a photogrammetry model. A check point is withheld from the fit to assess reconstruction accuracy. Distribution across the site, accurate survey and consistent height datums matter as well as the number of points.
A photogrammetry workflow jointly estimating camera geometry and scene structure from many overlapping images, commonly followed by dense surface reconstruction. Ground control points or accurately surveyed camera positions establish scale and georeferencing. Independent check points test accuracy rather than participating in the fit. A fine image ground-sampling interval does not alone establish equal vertical accuracy.
Three-dimensional reconstruction using two or more overlapping photographs from different viewing positions. Corresponding image points define viewing directions whose intersection estimates the surface position. Surveyed camera positions and orientations, camera calibration and ground control points establish the coordinate geometry. Ordinary optical stereo models the visible surface, which can be forest canopy rather than bare ground.
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Photogrammetry is a technique that involves capturing and interpreting photographic images to measure and analyze objects and landscapes in three dimensions. It uses photographs taken from different angles and positions to create accurate representations of the physical world, allowing for the extraction of spatial information. Key aspects of photogrammetry include: 1. **Data Acquisition**: Photogrammetry typically utilizes digital cameras, drones, or aerial platforms to capture images. The images should overlap to ensure accurate measurement.