Front Wall Clutter Rejection Methods in TWI

Through-wall imaging is characterized by strong reflections due to the building front wall that can impair the detection of the obscured scatterers. To mitigate this drawback, wall clutter rejection methods can be employed before imaging. In this letter, a clutter rejection method based on data entropy is compared to other literature methods such as the average trace subtraction, the differential approach, and the subspace projection method. It is shown that the entropy-based method is as effective as the other methods in removing front wall contribution, but at same time, it avoids unwanted filtering of the field scattered by the targets.