Hard Wall Imaging of Objects Hidden by Non-Penetrating Obstacles Using Modified Time Reversal Technique

One of the important current problems is imaging and detection of objects hidden by obscuring obstacles. There have been extensive works reported on “Through-Wall Imaging” in recent years. This paper extends the previous works to the case where the wall is non-penetrating and the diffraction around the edge becomes important. This hard-wall imaging is related to the historical problem of “Poisson Spot” and “Anti-Podal point.” This paper makes use of the modified time-reversal technique and GTD, and shows the formulations of the multistatic data matrix, eigenvectors and steering vectors to form the imaging function. Signal processing includes the multiplicative modified time reversal technique to eliminate the unwanted extraneous images. Numerical examples include comparisons between the modified and the conventional time-reversal imaging to show the effectiveness of the hard-wall imaging method.