The Accuracy of Photo-Based Three-Dimensional Scanning for Collision Reconstruction Using 123D Catch 2013-01-0784

An experiment was conducted to examine the validity of freely available photo-based 3D scanning software for generating accurate 3D geometry of a vehicle. Currently, 3D vehicle geometry is routinely captured using total station survey equipment, coordinate measuring machines (CMM), laser scanning, or traditional point-based photogrammetry. While these methods produce sufficiently accurate results for collision reconstruction, they have limitations that can affect practical implementation. For example, manual surveying with a total station, CMM or traditional photogrammetry are all limited to the production of coordinate data at discrete, pre-defined points. In addition, total stations, CMMs and laser scanning devices are also expensive and require a significant amount of time in the field with the vehicle. In contrast, photo-based 3D scanning allows a 3D mesh to be created of a vehicle simply from a series of photographs using a consumer-grade digital camera.

In this experiment, a vehicle was marked with point targets and photographed. The coordinates of the targets were then measured using: 1) A total station; 2) Traditional photogrammetry software; and 3) Photo-based 3D scanning software. The coordinates of the targets on the vehicle model produced through the photo-based scanning process were compared with the target positions measured via total station and traditional photogrammetry. The mean deviation between corresponding points on the photo-based scanning model and the traditional photogrammetric model was 3.2 ± 1.8 mm. The mean coordinate deviation between the photo-based scanning model and the total station data ranged between 3.4 ± 1.4 mm and 6.3 ± 3.1 mm.