Innovative Millimeter-Wave Imaging System for Detecting Metal Defects through Polyurethane Coatings

SARA’s PolyUrethane Millimeter-wave Imaging System (PUMIS) will image surface-metal defects through optically and acoustically “thick” coatings, such as those found on submarine exteriors, without needing to compromise the insulating layer. The device will be built in the form of a hand-scanner, imaging rust formations, de-bonding, and hairline metal cracks on the submarine. Image interpretation will be intuitive, enabling the operator to reject false positives due to changes in the submarine structure, such as metal curvature, thickness variation in the polymer, and mounting bolts. In-wire processing of the millimeter-wave backscatter caused by such defects will enable real-time imaging of the area under test, by way of a mobile PC or tablet, smartphone, or the monocle of a personal media viewer such as a MyVu. Nominal surface area coverage using the envisioned scan methodology will be 25-50 square feet per minute (end of Phase II), encumbered only by the operator’s ability to maneuver around the area under test. Because the system noise and background clutter is low, SARA’s long-term expectation is that, for coarse assessment, linear sweeps across submarine material may be executed as quickly as an individual can operate a squeegee, with coverage areas up to 30-50 square meters per minute.