Experimental Study of Robust and High-Resolution Ultrasound Imaging Algorithm with Adaptive Smoothing Techniques

Ultrasound imaging is an important technique with great potential for accurate nondestructive testing. Previously, we proposed a high-resolution 3-D imaging algorithm for UWB radar, the Envelope algorithm with adaptive smoothing techniques. The Envelope imaging algorithm utilizes the principle that the target boundary is expressed as an envelope of spheres determined by observed ranges, while the range smoothing techniques stabilize the estimated image produced by the Envelope algorithm by adaptively changing the range smoothing method. Numerical simulations confirm that the maximum error of this algorithm is less than 0.015 center wavelength. In this study, we apply the Envelope algorithm with adaptive smoothing techniques to high resolution 3-D acoustic imaging, which is a promising form of accurate nondestructive testing, and evaluate the performance of this algorithm with experimental data. The results verify that the proposed method achieves high-resolution 3-D acoustic imaging. The mean error of the estimated image is 6.1μm which corresponds to 8.2 ×10−3 center wavelength.