Preliminary studies of a novel air-coupled ultrasonic inspection system for food containers Original Research Article

Air-coupled ultrasound has been used to perform measurements on liquids and starch-based materials, within containers similar to those used in the food industry. The technique uses capacitance transducers with polymer membranes to generate ultrasonic signals in air over a reasonable bandwidth. Ultrasonic pulse-compression (UPC) is then applied to increase the sensitivity of signals transmitted through the containers. It will be demonstrated that various non-contact measurements are possible, including the detection of variations in consistency within starch-based liquids within a microwaveable food container, the detection of liquid level in polymer-based soft drink bottles, and the tomographic imaging of such containers to detect foreign objects.