Photogrammetry Research Paper

Photogrammetry is the science and art of extracting 3D information from any type of 2D satellite, aerial or terrestrial images. It is a measurement technology of obtaining reliable information about an object. There is no any physical contact between the measuring device and object to be measured. Therefore, it is also called a non-contact measurement technique and considered as a remote sensing technique. The term photogrammetry is old as term photography. It is derived from three different Greek words; photo means photographs, gram mean drawn and metry mean measurement. The purpose of photogrammetric measurement is to reconstruct three dimensional of an object either in digital (coordinates and derive geometric elements) or in graphical form

1.1.1. Close Range Photogrammetry Close Range Photogrammetry is a technique of deriving 3D spatial information about an object of real world from two dimensional photographs instead of measuring the object direct. It is a non-contact measuring technology in which multiple overlapped digital photographs are taken at a distance for measuring feature point of interest. Matthews (2008) describes that close range photogrammetry is not an entirely different from the traditional aerial photogrammetry and the same techniques used in aerial photogrammetry can also be applied to close range photogrammetry. But the advantage of close range photogrammetry over traditional aerial photogrammetry is that the cost of the entire process of acquiring, processing and analyzing has been reduced dramatically over the years and also terrestrial images can acquired with minimal field equipment. Close range photogrammetry has especially benefited from evolving low cost and efficient technology. Therefore, digital terrestrial photogrammetry is an efficient method in documenting variety of complex structures so that it can be used for several purposes like in

Concept of Close Range Photogrammetry Close Range Photogrammetry technique basically works on the principle of Triangulation. Photographs are taken from at least two different locations and for each location line of sight is developed. These lines of sight mathematically intersected to produce three dimensional coordinates of point of interest. In the figure 1.1 shown below there are four camera positions from where photographs are taken. In first step multiple overlapping of the scene are recorded by referencing 2D positions of feature point on two or more photographs then determination of 3D coordinates of these features happens via a process called “Photogrammetric Bundle