Stereoautograph

The stereo autograph (also stereo autograph) is a complex measuring instrument for stereoscopic analysis of aerial photographs. It combines (s) deliver ( within a thousandth of a millimeter) with partial automation of the measurement process.

The observer shall submit the evaluated aerial photos ( traditionally mostly photographic plates with dimensions of 21 × 21 cm) under two mechanically connected measuring microscopes. As he departs with measuring spindles and two crosshairs terrain stereoscopically (ie spatial visual impression ), registered the autograph by mechanically simulated lines of sight both the position coordinates and the height of the topography or the selected area or object points. Previously, the geometry of each image pair (inner and outer orientation) must be modeled by means of control points.

The first stereo Count for photogrammetry were designed in 1907 by Eduard Orel. From 1909 the unit from the Carl Zeiss company as " Orel - Zeiss'scher stereo Autograph " was built in Germany. From the 1950s, when the possibilities of modern surveying and construction technology also drove the importance of aerial triangulation in height, very complex instruments were built, semi-automatic methods of measurement ( terrain profiles, contours, etc.) allowed, had a footprint of up to several square meters and connection of extension devices such as paper tape punch or plotter enabled.

The best known, the model series of the Swiss company were Wild Heerbrugg ( large appliances A7 and A8, as well as hand-operated devices such as the table B8). In the 1990s, the digital photography began to enforce in the image measurement, which on the one hand brought the possibility of minor construction with itself, on the other hand continued the analytical photogrammetry to the highest accuracies and wide applications.