HISTORY OF PHOTOGRAMMETRY
PHOTOGRAMMETRY: This is the science of creating, producing image and photographs date back to the 1400’s believe it or not, Leonard de Vince” is one of the earliest explorers of the science. Since then other scientist continued this work on projective geometry mathematically. In 1525” Albercht duere” used law of perspective drawing.
From this same idea scientist began developing mathematical principles of a perspective image using space reaction” (determining the coordinates of a point from which a picture from two or more images) to find a point in space from which is made.
The actual relationship between projective geometry and photogrametry was first developed by Rostrums’ and Guido Haick in Germany in 1883.
Since then the science went through four development cycles.
ANALOG PHOTOGRAMMETRY (1910-1950)
The invention of the device ‘’Stereo comparator” by pullfrich, in 1909 marks the first revolution of the photogrametry, through which could make easy the work of users surprisingly, thanks to the replacement of many mathematical calculations by optical-mechanical devices.
In 1911, the Austrians Theodore Scheimpflug creates a successful method of rectification of aerial photographs.
The analogue rectifiers are replaced by the famous analogical stereo plotter, allowing stereoscopic vision using asteroscopic pair. Many stereo plotters, especially the swiss and germans, like wild, zeiss and kem had the opportunity to obtain topographic charts with amazing precision. Here the information acquired is recorded on paper or other media placed on top of a drawing table, which is connected mechanically or electrically to stereo plotter.
Obviously such devices, highly specific, require and deep training and the ‘’photogrammetist’’ becomes an essential part in photogrammetric process.
We can consider yet another classification-semi-analytical-in which the electronic data processing allowed the data would be entered directly into systems Computer Aided Design (CAD), the drawing table was eliminated, some other operations, in addition to registration, began to be assisted by computer.
The field work becomes easier by the introduction of the aerial triangulation process, allowing deifying ground control points at the laboratory.
Alongside these developments, starting appears specific cameras, called metric cameras which have mechanisms, to print in the photo relevant information about the image coordinate system, adding further the correctness of the made measurements. A very good example is the fiducially marks. They are present in all photos and their photos coordinates are determined in the laboratory; this is the time of producing and empowering of a lot of organizations together all stakeholders in the area; the ISP ( International Society For Photogrametry). Now the ISPRS (International Society for Photogrametry And Remote Sensing) was founded in 1910 by E Dolezal; Austria.
ANALYTIC PHOTOGRAMMETRY (1951-1990)
The invention/introduction of computer in 40;s began the transformation in the photogrammetric processes and the large calculations needed , that the where replaced by mechanical devices, started to be executed on computer.The first study in this area was developed in 1953 by Dr. Helmut Schmidt of the ballistics research laboratory in Aberdeen, Maryland, USA. This study established the basis of analytical photogrammetry, including the process matrix, the solutions by least squares (a type of statistical method), the simultaneous solution using multiple images and complete analysis of error propagation.
In 1957, the finish Uki Helava develops the concept of analytical stereo plotter, using servomechanisms to measure the coordinates of fiducial marks on images. Perform all other calculations simplifying very much the process. The first analytical stereo plotter was presented in the congress of the ISP (now ISPR) in 1976. Thereafter, such equipment revotionalized the concept of photogrammetry, allowing serial triangulation in larger books and the use of ordinary cameras (non-metric)
Digital photogrammetry (1990-date)
The digital photogrammetry was born in the 80s, having as a great innovation the use of digital images as a primary data source. The digital image can be acquired directly from a digital camera, or even by scanning or analog.
In the 1990a, this branch of photogrammetry has been used extensively, thanks to the development of computers with sufficient capacity for the interactive processing of digital images, generating high volume of data.
The rest of the processing takes place in a similar way to the analytical photogrammetry, and is now possible to create digital products (apart from digital charts) that require highly developed computer processing, such as ortho images (images with orthogonal perspective) and digital mosaics, as a result of several images.
The devices currently used have also changed, being called digital photogrammetric stations (work stations entirely devoted to photogrammetry).
If common computers receive specific hardware and software, they can also be used for this purpose.
There is a difference between digital photogrammetry and photogrammetry supported by computer.
In order not to lose the experience of years of work by expert operators and also to increase the expectancy for yet effective analogue and analytical stereo plotter, computers were connected to them, allowing digital data as output, in computer file (usually a format compatible with many programs for CAD- Computer Aided Design available). Still, these devices may not be related to digital photogrammetry, since the input data entry is still in analog mode (photo printed on film). Even the analytical stereo plotter, that makes the rest of the processing in computational, considered it as data input.
Only in digital photogrammetry we have a complete computational analysis of the whole process.
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