Accuracy Comparison of 3D Structural Models Produced via Close-Range Photogrammetry and Laser Scanning

This paper presents a comparison study of building measurements performed on 3D models generated by two different approaches. In one approach, the models were produced via close-range photogrammetry. Such models are based on still-frame photographs, post-processed with commercially available photogrammetric software. The second approach was the generation of 3D point-cloud models via laser scanning. For this purpose, a simple one-story structure was chosen. Students, from Georgia Southern University, established accurate benchmarks within a closed traverse to serve as standard reference points for all measurement comparisons. Several physical target points were then marked on the exterior walls of the structure. These target reference points were then measured with an accurate total-station instrument. After photographs were taken and laser scanning of the structure performed, the coordinates of these target reference points were also determined from the respective models. These coordinates were then compared with the ones obtained with the total-station instrument. Coordinates and distances from each procedure were compared to determine relative discrepancies and accuracies. The results of this study demonstrate that the photogrammetry approach can provide accurate information, comparable to measurements produced with total stations and laser scanners.