Section

Photogrammetry is a technique that allows the definition of the position, the shape and the size of objects on the ground, using appropriate photographic images called frames, of the same objects, taken from different positions.
A frame is a central perspective, in which the segments that connect any point of the object with its corresponding image on the photographic plane meet at a point called a perspective center.
Using two frames that represent the same object it’s possible to define its geometry. In fact, knowing the exact position of the homologous points, ie points that represent the same object on two frames, the spatial position of the two photographic images and the two prespective centers, the object can be geometrically defined as intersection of the two rays that connect the two homologous points with the corresponding prespective centers.