“…Studies have been devoted to the improvement in accuracy, robustness, and efficiency of photogrammetry. Ehrhardt et al (2013) revealed that the accuracy of photogrammetry largely depends on the parameters of the photographic system, including camera angle, shutter speed, the amplitude of measured displacement, and so forth. Li and Wang (2013) discussed the influences of the baseline distance, optical axis, baseline angle, projection angle on the measurement accuracy in detail.…”