USDA researchers tested airborne ultrasound for locating hidden defects in cattle hides in a study reported in 2017.
How the test worked
A USDA Agricultural Research Service report dated 17 August 2017 describes low-frequency airborne ultrasonic signals sent through a cattle hide to a receiver. Defects changed the received signal. Researchers reported nondestructive detection and collected data related to toughness, strength and stiffness.
Research stage
The report described a research prototype and possible industrial use. It did not give specifications for a current commercial machine or its performance on a production line. The accompanying USDA photograph shows the ultrasound research equipment from the same period.