Aerial photography (aerial photography) is the photographing of terrain and individual objects from aircraft (aircraft, helicopters, unmanned aerial vehicles, artificial Earth satellites) using an aerial camera. Aerial photographs result in aerial photographs, abbreviated aerial photographs.
Aerial photography, aerial photographs of the terrain, types of aerial photographing and aerial photographs of the terrain.
The types of aerial photographing are determined depending on the type of aerial camera and the position of its optical axis during photographing, on the time of year and day, on the methods of implementation and on the photographic materials used. The main types of photography are:
– Planned and promising. By the position of the optical axis of the aerial camera at the time of photographing.
– Personnel, slot, panoramic. By type of aerial camera.
– Single, route, area. By methods of execution.
– Daytime, nighttime. By time of day.
– Black and white, color, spectrozonal.
– Summer, winter, transition. By season.
The types of aerial photographs are determined mainly by the types of photographing. For example, as a result of perspective photography, perspective aerial photographs are obtained, panoramic photographs result in panoramic photographs, etc..
It is performed when the aerial camera is in such a position that its optical axis at the time of exposure coincides with the vertical line or deviates from it by an angle not exceeding the set value (3 degrees for aerial photography for cartographic purposes and 25 degrees for reconnaissance purposes). In planned aerial photographs, the perspective on the eye is not perceived.
The scale of the planned aerial photograph of the flat and hilly terrain is almost constant, and all measurements on it can be performed in the same way as on the map. The most common scheduled aerial photographs. They allow you to determine the shape, actual size and location of objects and are widely used for measuring and cartographic purposes..
It is produced at a given inclined position of the optical axis of the aerial camera. Typically, for perspective photography, cameras are installed at an angle of 45, 60 or 75 degrees. The scale of the perspective aerial photograph is variable: in the foreground – large, gradually decreasing to the background. Prospective aerial photographs provide a more visual representation of the enemy’s terrain and targets and are mainly used to study water barriers, hydraulic structures, mountain passes, access routes to enemy targets, and also for reconnaissance of targets heavily covered by air defense systems.
Advanced photography allows you to detect objects that were masked by using horizontal coverings and crowns of free-standing trees. However, in promising aerial photographs, only the foreground is well read, and the background is poorly visible.
In contrast to the usual (personnel) one, it is produced by a special (slotted) aerial camera, in which the film is exposed through a narrow, constantly open slit onto a film being rewound at the plane’s flight speed on a photographing scale. The slit aerial photograph is a continuous (without gaps) photographic image of a strip of terrain in the form of a roll over the entire length of the exposed film.
Slit photography is performed, as a rule, with the position of the slit, which gives a deviation of the optical axis from the vertical by 45 degrees in the plane of flight (forward or backward). As a result, axonometric aerial photographs are obtained in which objects are viewed from above and from one of the sides.
The measuring properties of axonometric aerial photographs differ from the planned personnel aerial photographs by a small discrepancy in the longitudinal and transverse scales (up to 10-15%). Slit photography can be used in low light areas (for example, at dusk).
It is carried out by a special (panoramic) aerial camera, in which the lens rotates during exposure to the film in a plane perpendicular to the direction of flight. Panoramic photography provides a large width capture of the photographed area (from horizon to horizon). On panoramic aerial photographs in the central part, a planned image of the area is obtained, and on the sides – a promising.
It is used for reconnaissance of individual targets (usually at night). In all other cases, route (predominantly) and areal photography is used with overlapping between images in the route (longitudinal) of 20% or more and between routes (transverse) of 30-40%. Two-, three- and four-way photographing can be carried out from one flight route, but with a special aerial camera installed in a rocking installation. In perspective photography, longitudinal overlap is considered to be in the main horizontal. It should be approximately 50%.
It is carried out with artificial lighting of the terrain using pyrotechnic means (photobombs, photo rockets, photographic cartridges) or electric aircraft lighting installations (SOU). Night aerial photographs obtained under illumination with photo bombs differ from daytime ones in that the brightness of the photo image in night photographs can be uneven, and the shadows from towering objects will be directed in different directions. When illuminated using SDAs, there are no shadows from towering objects on planned aerial photographs.
It is produced on a film consisting of several layers, simultaneously in several different areas of the spectrum, in which the reflective properties of the objects and the background surrounding them have noticeable differences, due to which the visible contrast is enhanced between them. By spectrozonal aerial photographs, you can explore some objects disguised as the color of the surrounding background, identify additional permeability characteristics, etc..
Photographing a radar image of the area.
It is carried out from the screen of radar equipment installed on an airplane. A radar image of the area is obtained at any time of the day and in any weather. Using an optical system, a radar image is projected onto photographic film moving at a speed proportional to the speed of the aircraft. As a result, a continuous radar image of a strip of terrain in the direction of flight is obtained on film.
Based on materials from the Handbook of Military Topography.
A. M. Govorukhin, A. M. Kuprin, A. N. Kovalenko, M. V. Gamezo.