New Construction Verification by Measurement of Ovality and Deflection with 3-D LADAR

Described is LADAR-based system for measuring Ovality and Deflection. The system is unique in that it employs a three dimensional scanning technique that is robust to imaging geometry. More specifically, the system is able to produce accurate cross-sectional analysis even where there is a large divergence of the imaging axis with the central pipe axis. This capability becomes increasingly critical as the diameter of the host pipe increases. In large diameter pipe, even small divergence angles can result in significant diametric measurement errors. Results from inspection of nearly 25,000 linear feet of newly constructed 30, 36, and 42 inch Centrifugally Cast - Glass Fiber Pipe (CC-GFP) by the aforementioned system are presented. True cross-sections extracted from the 3-D point cloud data identified five segments that exceeded the 5% deflection limitation for CC-GFP pipe 30 days after installation. Measurements were verified by direct manual and laser line measurement and found to be accurate to within 1/16 of an inch. More importantly, the ability of the Laser Radar (LADAR) system to quantify the deformations was an important aspect in the repair strategy and ultimately led to design changes that will improve the operational life of the installed pipeline.