Enhanced Discrimination for Boundary and Material of Buried Objects in Concrete Structure using Microwave Subsurface Radar

In this report, a novel signal and image processing method for microwave subsurface radar is proposed, which enables to estimate the internal construction in concrete structures. By using proposed method, enhanced information of buried objects such as boundary and material are discriminated. As the objects are buried near the concrete surface, signal processing is complicated because a reflected wave is often interfering with a transmitting wave in an observed signal. In order to reduce an influence of the interference, transmitting wave subtracting method is adopted, which calculates the difference between the observed signal and a typical transmitting waveform identified from the observed signal without buried objects, and boundary and material of the buried objects are discriminated precisely. Next, a boundary back projection histogram method is newly proposed. The boundary model fitness whose shape is the normal distributions having characteristics of the original model fitness is introduced to sharpen the boundary on electrical characteristics in propagation medium (which represents the boundary of the buried object). The boundaries of the buried object are discriminated clearly in the back projection images calculated by using boundary model fitness. An effectiveness of these proposed methods has confirmed by experimental application to several concrete structure samples