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Geometric correction

Geometric correction in remote sensing refers to the process of removing geometric distortions from images acquired by a sensor. These distortions can be caused by factors such as sensor tilt, altitude, and terrain curvature. The goal of geometric correction is to produce an image that is geometrically accurate, meaning that the features in the image correspond to their true locations on the ground.


One commonly used method for geometric correction is called rectification. This involves transforming the image so that it is projected onto a uniform scale, such as a map projection or a digital elevation model. This can be done using a process called orthorectification, which involves using information from the sensor's attitude and position, as well as a digital elevation model, to correct for distortions caused by terrain relief.


For example, an image of a mountainous area acquired by a sensor mounted on an aircraft may appear distorted due to the angle of the sensor and the shape of the terrain. After orthorectification, the same image would appear as if it had been acquired from directly above, with the terrain appearing flat and the features in the image corresponding to their true locations on the ground.




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