Accurate boundary extraction method by range points migration for microwave non-destructive monitoring

Microwave ultra-wide band (UWB) radars with higher range resolution and penetration ability for low lossy medium are promising as non-destructive testing for aging transportation infrastructure or non-invasive internal inspection for human body, such as cancer or brain stroke detection. The traditional delay-and-sum (DAS) based imaging algorithm inherently suffers from an insufficient resolution to identify a detailed structure of buried targets. As promising alternative, the range points migration (RPM)-based boundary extraction approach has been developed. This paper focuses on the acceleration for this method, by exploiting the feature of Envelope outer boundary extraction. The results from numerical simulation and experimental data demonstrate that our proposed method accurately reconstructs the three-dimensional shape of air cavity buried in concrete object with considerably reduced computational cost.