摘要
Empirical mode decomposition has its unique advantages in dealing with non-linear,multi-component signal.Subjected to the sampling rate and the fact that frequencies of the individual components usually lie close to each other or within an octave,each intrinsic mode function is not composed of a single frequency component.With the help of the combination effect of masking signal and sampling rate interpolation,the result of intrinsic mode functions is significantly improved relative to the traditional EMD decomposition.The improved decomposed intrinsic mode functions are used to image the defects inside a concrete structure with the synthetic aperture focusing technique.The location of the defects can clearly be found,and practice has proved the feasibility of this improved method.