A NON-METRIC CLOSE-RANGE PHOTOGRAMMETRIC SYSTEM FOR MAPPING GEOLOGIC STRUCTURES IN MINES

The collection of structural data in mines is an integral part of the search for geologic indicators of mine-roof instability. We used close-range photogrammetry in conjunction with conventional geologic field methods to collect the necessary data. Stereopairs of photos were taken with 70-mm and also with 35-mm non-metric cameras. The structural geologic data were acquired and displayed by a computerized, analytical approach. Object-space control was obtained by using a modular aluminum frame consisting of eight cubic sections that can be assembled in various configurations. Photocoordinates were measured with a stereocomparator and reduced by the Direct Linear Transformation (DLT) method, which involved 11 transformation unknowns for each photograph. The least-squares method was used to determine the equations of the planes, using four to ten point measurements for each plane. The four tests described in this paper show that an analytical photogrammetric system utilizing a small-format non- metric camera meets the accuracy requirements of geological work, and that the method is not only technically feasible but in fact practical to use in geological mapping.