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Preliminary Processing

Prior to the primary processing, a produced image must be taken through the preliminary processing stage, which consists in geometric, radiometric and atmospheric corrections.

Geometric correction is undertaken to eliminate geometric distortions caused by the fact that an image of Earth surface shot by a device directed exactly downwards contains an undistorted picture only in the center of the image, and distances between the image points when shifted to the edges and respective distances on the Earth become increasingly different.
Such distortions are corrected in the process of photogrammetry.

Radiometric correction includes two types of corrections:

  • Radiometric correction of distortions caused by specifications of a survey equipment used;
  • Radiometric correction of distortions arising due to sun angle and relief forms (elimination of defects of sunspots and shadows).

Atmospheric correction is undertaken to remove various distortions caused by atmospheric effects.

Atmospheric correction is undertaken to remove various distortions caused by atmospheric effects. During image preprocessing, systematic radiometric and geometric errors are removed from the data. Image enhancement allows you to transform it into a form that is most convenient for visual and automated analysis and is used to emphasize the most important features of the image and further facilitate the process of data interpretation.

After the remote sensing processing has been carried out, they can be used to create high-quality cartographic products, for example, for updating the topographic base and decoding.


Image before and after atmospheric correction