Surface roughness imaging using the acoustic emission inducedby the dynamic radiation force of ultrasound

High frequency ultrasound imaging systems are traditionally used in industry to obtain high resolution images of solid surfaces, and in some cases, to evaluate surface roughness. In this study we show that imaging fine surface roughness in the order of few microns is achievable at audio range frequencies (kilohertz range) by using the vibroacoustography (VA) technique. This technique allows one to image surface roughness on the basis of the ultrasound radiation force stimulated acoustic emission in a standing ultrasound wave field. Images obtained here demonstrate that VA may be used as a powerful tool for nondestructive inspection and imaging of surface roughness.