Published in Scientific Papers. Series "Journal of Young Scientist", Vol. 7
Written by Marius-Cornel NICOLAE, Alin-Ionuţ POPA
The paper aimed to present the main steps necessary to determine photo-coordinates and the process to correct them for systematic errors, such as radial distortion, refraction and earth curvature which is also known as image refinement. Image preprocessing is a technique which is used to enhance raw images received from aerial photocameras, placed on drones, airplanes, satellites or other aircrafts for various engineering applications with a good accuracy. Photogrammetric original data obtained are usually geometrically distorted due to the acquisition system and the movements of the platform. So, we inserted the diapositives into the measuring system (e.g. stereo-comparator or analytical plotter) and measured the fiducial marks in the machine coordinate system. Then, we compute the transformation parameters with a similarity or affine transformation. The transformation establishes a relationship between the measuring system and the fiducial coordinate system, and translates the fiducial system to the photocoordinate system. Finally, we corrected photo-coordinates for radial distortion (by linearly interpolating with the values given in the calibration certificate) and other systematic errors.
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