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The application of photogrammetry to the reconstruction of automotive accidents has been well documented and many techniques are available to the reconstructionist. However, the accuracy that can be expected from a photogrammetric project can vary by method and by application. Greater understanding of the factors affecting the accuracy of a photogrammetric reconstruction is desirable. Specific variables affecting the accuracy of 3-D, non-metric, analytical photogrammetry were studied using the commercially available software package, Eos Systems’ PhotoModeler. The 3-D co-ordinates of targets on a vehicle were first surveyed and then photographed with standard 35 mm camera equipment. The knowledge of camera properties, the method of image generation, photograph cropping, use of fiducial markings, and the number of control points were investigated to determine their relative effects on the accuracy of the solved coordinates.

Without good-quality measurements taken at the time of an accident the analyst is faced with the need to extract measurement data from incident scene photographs. This paper discusses the history and development of the mathematical model for two-dimensional (2D) single exposure analytical photogrammetry, presents the software PC-Rect, and compares the analytical results obtained with PC-Rect to survey results. The sensitivity of the analytical results to the variation in such parameters as subject distance, camera height, digital photograph resolution, and bitmap density is discussed. The concept of using the directly rectified scanned photograph in the reconstruction task is introduced, and the utility of performing the dynamic simulation directly on the rectified photograph is discussed.