Photogrammetry

Photogrammetry is a technique used to obtain reliable measurements or information from digital or analogue photographs (photo-grammes). It is often classified as a type of remote sensing, as objects are measured without being touched. Both far range and close range, and aerial (usually far range) and terrestrial (usually close range) photogrammetry can be used. ‘Aerial photogrammetry’ or ‘aerophotogrammetry’ are often used as synonyms for ‘aerial survey’.

Most simply, photogrammetry can be used to find the distance between two points by measuring on a photograph with a known scale. However, as photographs convert the three-dimensional world into a two-dimensional image, photogrammetry can reverse this process by reconstructing the original three dimensions. In order to achieve this, two or more photographs taken from different angles are needed. This method is called stereophotogrammetry, or 3-D photogrammetry, and uses triangulation to estimate the 3-D coordinates of objects.

In triangulation, a line of sight (or ray) from the camera to a particular point on the object is created for each photograph; coordinates can then be calculated, using algorithms, by seeing where these lines intersect. This is similar to how theodolites work in surveying.

Photogrammetry can then be used to create topographical maps, 3-D models, drawings or rectified or ortho images (where a number of images of the same place or object are projected onto a common image surface). It is also used by archaeologists when plans of large or complex sites are needed and time is limited.

Related methods include: 3D Modelling - vector, Geo-referencing and projection, GPS and total station surveys, Photography and Remote sensing.

tool: Adobe Photoshop

Adobe Photoshop is an editor for still images. It is equipped with a diverse range of processing tools, enabling users to create or modify content through the use of drawing tools, filters, or other plug-ins.
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2d graphic designPractice-led research
2d illustrationPractice-led research
2d modelling - rasterData structuring and enhancement
2d modelling - vectorData structuring and enhancement
2d scanning and photographyData capture
3d graphic designPractice-led research
3d modelling - interactiveData structuring and enhancement
3d modelling - vectorData structuring and enhancement
3d modelling - vectorPractice-led research
3d scanningPractice-led research
Graphical interaction (asynchronous)Communication and collaboration
Graphical renderingData structuring and enhancement
Image enhancementData structuring and enhancement
Image feature measurementData analysis
Image manipulationPractice-led research
Image restorationData structuring and enhancement
Image segmentationData analysis
PhotogrammetryData structuring and enhancement
PhotographyPractice-led research
PhotomontagePractice-led research
VisualisationData analysis
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GraphicConverter, 36-image converter

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