Corrosion Mapping (Large Structure Inspection). Traditional inspection of large structures requires local access, which is often costly. The LSI system approach provides full ultrasonic B-SCAN, T-SCAN, LRUT, visual and UT weld inspection (Shear and TOFD) using a fast remote controlled crawler. The LSI system has two powerful magnetic tractors that carry a range of inspection hardware and may be configured for most inspection tasks. LSI was developed by Scanning Systems International, now part of the MISTRAS Holding NDT automation division, and has been proven worldwide. Applications where LSI is currently being used include storage tanks, heat exchangers, storage spheres and bullets, columns, pipelines, ship hulls.