GPR measurement of the diameter of steel bars in concrete specimens based on the stationary wavelet transform

Ground penetrating radar (GPR) is a valuable non-destructive method for detecting steel bars in reinforced concrete structures. Measuring the diameter of the steel bars is difficult and few previous experiments have been successful. We compare the difference of discrete wavelet transform (DWT) a and stationary wavelet transform (SWT) and make the contour map of SWT detail coefficients, then find that SWT is an effective method to measure the diameter of steel bar. We also discuss our choice of the wavelet basis that best interprets the raw GPR data.