developments of photogrammetry qiu sheng z3299159, gmat9205, s1 2010
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Developments of Photogrammetry
Qiu Sheng z3299159,
GMAT9205, S1 2010
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Introduction of photogrammetry
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Three types of photogrammetry
1851 1960s~1980s 1980s~today
Analogue photogrammetry
Analytical photogrammetry
Digital photogrammetry
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Analogue photogrammetry
Obtain a terrain model by simulating with two projectors the intersection of homologous rays from two cameras;
Mechanical or optical principles for the solution ;
Using space rods or optical projection;
Main products during this phase were topographic maps
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topographic maps
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Analytical photogrammetry
Computer replaces some expensive optical and mechanical components
Calculation with mathematics computation to solve the relationship between the coordinates of the image and object point
Relying on pure mathematics rather than simulation devices
Main developments were analytical aerotriangulation, analytical ploters and orthophoto projectors, they could be topographic map, but can also be digital products, such as DEMs
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Digital photogrammetry Digital images stored and processed on a
computer and could be scanned from photographs or directly captured by digital cameras;
Each picture element (pixel) has its known position and measured intensity value
Photographs are digitized before processing into picture elements with different grey levels
The final results of output can be topographic maps or the products in digital form, such as digital maps , DEMs, and digital otrhophotos saved on computer storage media.
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Advantage of digital photogrammetry
Digital softcopy workstations can be used rather than expensive plotting devices requiring special hardware
Data transfer is simpler with regard to plotting results Digital image processing techniques can be used for image
enhancement digital image processing render possible the automation of
photogrammetry measurement tasks
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Application of digital photogrametry
