Photogrammetry
Science of obtaining reliable measurements from photographic images.
Photogrammetry is the science and technology used to gather reliable information about physical objects and the environment by recording, measuring, and interpreting photographic images, as well as patterns of electromagnetic radiant imagery and other phenomena. Although the method was invented by Aimé Laussedat, the term "photogrammetry" was introduced by German architect Albrecht Meydenbauer in his 1867 article "Die Photometrographie."
There are several types of photogrammetry. One involves extracting three-dimensional measurements from two-dimensional data, such as images. For instance, if the scale of an image is known, the distance between two points on a plane parallel to the photographic image plane can be calculated by measuring their distance on the image. Another type extracts accurate color ranges and values—like albedo, specular reflection, metallicity, or ambient occlusion—from photographs of materials for physically based rendering. Close-range photogrammetry involves taking photographs from a shorter distance than traditional aerial or orbital photogrammetry. Analysis can be applied to a single photograph, or it can use high-speed photography and remote sensing to detect, measure, and record complex 2D and 3D motion fields. This is done by feeding measurements and imagery analysis into computational models to progressively estimate the actual 3D relative motions with increasing accuracy. Originally used with stereoplotters to plot contour lines on topographic maps, photogrammetry now has a wide range of applications, including sonar, radar, and lidar.
**Methods**
Photogrammetry draws on methods from fields like optics and projective geometry. Digital image capture and photogrammetric processing involve several defined stages that produce 2D or 3D digital models of the object. The data model indicates what type of information can be input and output. The 3D coordinates define the locations of object points in space, while image coordinates define where those points appear on film or an electronic imaging device. A camera's exterior orientation describes its location in space and viewing direction, while its inner orientation defines the geometric parameters of imaging, primarily the lens's focal length but also lens distortions. Additional observations are important: scale bars (a known distance between two points) or known fixed points conn
- field
- Science and technology of obtaining information from photographic images
- known_for
- Extracting three-dimensional measurements from two-dimensional data; stereophotogrammetry; close-range photogrammetry; integration with LiDAR and radar
- inventor
- Aimé Laussedat (method); Albrecht Meydenbauer (term)
- first_use_of_term
- 1867 article 'Die Photometrographie'
Lore & Background
Photogrammetry uses methods from many disciplines, including optics and projective geometry. Digital image capturing and photogrammetric processing includes several well defined stages, which allow the generation of 2D or 3D digital models of the object as an end product. The 3D coordinates define the locations of object points in the 3D space, while image coordinates define the locations of the object points' images on the film or an electronic imaging device. The exterior orientation of a camera defines its location in space and its view direction, and the inner orientation defines the geometric parameters of the imaging process, primarily the focal length of the lens but also lens distortions. Algorithms for photogrammetry typically attempt to minimize the sum of the squares of errors over the coordinates and relative displacements of the reference points, a minimization known as bundle adjustment, often performed using the Levenberg–Marquardt algorithm.
A special case, stereophotogrammetry, involves estimating the three-dimensional coordinates of points on an object employing measurements made in two or more photographic images taken from different positions. Common points are identified on each image, and a line of sight can be constructed from the camera location to the point on the object. It is the intersection of these rays (triangulation) that determines the three-dimensional location of the point. More sophisticated algorithms can exploit other information about the scene known a priori, such as symmetries, in some cases allowing reconstructions of 3D coordinates from only one camera position. The collection of images for the purpose of creating photogrammetric models can be called polyoscopy, after Pierre Seguin.
Photogrammetric data can be complemented with range data from other techniques. Photogrammetry is more accurate in the x and y direction while range data are generally more accurate in the z direction. This range data can be supplied by techniques like LiDAR, laser scanners, white-light digitizers, and any other technique that scans an area and returns x, y, z coordinates for multiple discrete points (commonly called 'point clouds'). Photos can clearly define the edges of buildings when the point cloud footprint cannot. It is beneficial to incorporate the advantages of both systems and integrate them to create a better product.
Reader's Guide
Photogrammetry has evolved from its beginning with stereoplotters used to plot contour lines on topographic maps to a very wide range of uses including sonar, radar, and lidar. It is used in fields such as topographic mapping, architecture, filmmaking, engineering, manufacturing, quality control, police investigation, cultural heritage, and geology. Archaeologists use it to quickly produce plans of large or complex sites, and meteorologists use it to determine the wind speed of tornadoes when objective weather data cannot be obtained. In filmmaking, it was used to combine live action with computer-generated imagery in movies like The Matrix, and extensively to create photorealistic environmental assets for video games including The Vanishing of Ethan Carter and Star Wars Battlefront. The main character of the game Hellblade: Senua's Sacrifice was derived from photogrammetric motion-capture models taken of actress Melina Juergens. In collision engineering, photogrammetry is used to determine the exact deformation present in a vehicle from crash scene photographs, relating to the energy required to produce that deformation and thus the velocity at time of impact. Subsea photogrammetry applications are numerous in the marine energy sector, including integrity monitoring of offshore wind turbine foundations, assessment of anchor chain wear, inspection of cable protection and burial systems, and overall evaluation of offshore structures. It also plays an increasing role in maritime and river civil engineering for inspecting port quays, dikes, dams, and other hydraulic structures, improving monitoring of structural changes and reducing costs.
Did You Know?
- The term 'photogrammetry' was coined by German architect Albrecht Meydenbauer in his 1867 article 'Die Photometrographie.'
- Stereophotogrammetry involves estimating 3D coordinates from two or more photographic images taken from different positions using triangulation.
- Photogrammetry was used extensively to create photorealistic environmental assets for video games including The Vanishing of Ethan Carter and Star Wars Battlefront.
- Subsea photogrammetry is used for integrity monitoring of offshore wind turbine foundations and inspection of cable protection systems.
More in Spatial Analysis & Gis 1-24
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record