The 50mm fixed lenses are the most used in the photogrammetric field because of the little field distortion they produce, while other lenses such as wide angle or fisheye are discarded from photogrammetric use, because they obtain the opposite effect. Zoom Lenses: Zoom lenses, are the most consumed throughout the world, because the big companies have manufactured these lenses as a default item for the sale of their cameras, these are lenses adaptable to lighting conditions, have a good image quality, are easy to use.įixed Lenses: These are fixed lenses, which have a single focal length so they cannot physically zoom, they are lenses that capture a large amount of light, which makes them able to work efficiently in places with low illumination. Without the camera lens and its lens, the rest of the mechanism could only capture the ambient light, this is where we find the term photographic focal length, this is measured in mm and is the representation of the distance between the sensor and the lens, so the longer the distance the smaller field of view is possible to capture, as it is the manual zoom is the one that can adapt this magnitude within the parameters of the lens. Lenses can be interchangeable in SLR cameras and is one of the most important parts of the camera’s operation and on it depends largely both the effect and the quality of the image captured. One of the main mechanisms of cameras are the lenses or photographic objectives, these parts are usually the most striking of the whole camera, usually consist of a cylindrical plastic shape topped with a glass on its outer base, this is the lens, a simulation of the human eye. This gradual pattern to be applied until the last cm of the element to be documented is captured. Photographs must be taken with a specific methodology so that there is an overlap of more than 70%, so each photograph must capture 70% old information and 30% new information. The Mobile phone cameras or the commonly used reflex cameras are the main tools of photogrammetry. New technologies for obtaining 3D data CamerasĬameras: Cameras are the main tools used within the photogrammetric technique, these are responsible for capturing images taken from angles and concise positions to obtain from them the subsequent 3D documentation. The more times a point is collected, the more accurately it is represented, and the process is carried out as shown in the images below.Īn overlap of more than 70% is always recommended in order to make the process of linking and processing points more efficient. The programme creates homologous points by analysing these common areas of overlap, selecting common points. These overlapping areas are the common zones and parts existing between 2 or more photographs. The photographs taken of the object, property, building or land in question are loaded into a special program where the computation is developed, creating homologous points by overlapping the photographs, taken with concise angles and shots to correctly develop their union, interspersing perfectly visible parts that serve the program to select and compile them, thus creating the overlapping areas. The main computational tool is carried out by finding homologous points in the different photographs, through this process the relative distances between the point and the photogrammetrist are calculated, in order to triangulate and assign a coordinate on the X and Z axes to that point.
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