Parallax bar heighting experiment with metric camera and large format camera photography

Abstract

A photographic stereopair of the Metric Camera (MC) and another one of the Large Format Camera (LFC) covering parts of the Red Sea Hills in Sudan were evaluated for height accuracy using the parallax bar heighting technique. X-parallaxes of a number of points on the two stereo models were measured and used to compute the crude heights of the points. Corrections to the crude heights were then computed using different mathematical algorithms and a set of well-defined control points. Discrepancies between corrected (computed) heights and known heights of another set of points were used to compute the root-mean-square errors of height measurement. The results show that Shepard's interpolation or a higher degree polynomial can produce height errors of the order of :t 53 m. This error value may serve a useful purpose in some basic thematic applications where high height accuracies are not of paramount importance.