There has been a growing interest to develop remote sensing technologies to quickly asses the condition of bridges while minimizing traffic disruptions and limiting inspection crews' exposure to traffic. Currently, the calculation of the National Bridge Inspection (NBI) Rating for a bridge deck is done by inspectors visually inspecting the bridge deck. 3D optics is an innovative technology that can help assess bridge deck condition while at the same time enhance the ability to preserve the data for future reference and decision making. 3DOBS (the 3D Optical Bridge-evaluation System) was developed to address these issues while at the same time providing data can be used to understand changes in condition in the future. The system is comprised of standard Digital Single Lens Reflex camera (DSLR) that is mounted to a vehicle, close-range photogrammetry software, and an automated spall detection algorithm. The camera is driven over each lane of the bridge collecting photos with a 60% overlap and then processed in the photogrammetric software. The resulting output is a Digital Elevation Model (DEM) of the bridge deck. This is then processed through the spall detection algorithm to identify spalls, calculate area and volume of individual spalls, and percent of the total bridge deck that is spalled. This information can be integrated into bridge management systems and decision making processes on bridge preservation.

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