Semi-automated topographic mapping of fracture surfaces through stereo-photogrammetry

By equipping a standard Hilger-Watts stereo-photogrammetry viewer with transducers, sets of (X, Y, Z) coordinates corresponding to features within fracture surfaces can be obtained. Transducers mounted so as to monitor the the X and Y translations of the viewing tray, when incorporated with a third transducer to measure the rise and fall of the light spot used to measure apparent height changes, supply three voltage signals corresponding to the …