High Resolution Ultrasonic Imaging
High frequency ultrasonic systems in the range of 10-400 MHz allow unprecedented vision inside objects with relatively high resolution.
This talk provides some historical background to ultrasonic imaging, transducer development, and reviews the basic theory and the underlying physics. Various techniques and capabilities with emphasis on recent applications are described. It is shown, for example, that internal cracks with separations sizes greater than 200 A in a thick fatigued metal part can be identified with lateral resolution on the order of 100 um.