An approach to remove the clutter and detect the target for ultra-wideband through-wall imaging

Through-wall imaging (TWI) is important from the point of view of rescue operations and surveillance. Several researchers have been working in this field but have still not obtained any concrete results. TWI using narrow band radar faces the problem of low resolution whereas ultra-wideband (UWB) radar provides better resolution, classification and low loss for the imaging signals. TWI faces many challenges in collecting the scattered electromagnetic fields from objects located behind the wall and also in processing the data in order to detect, locate and image the object. One of the important factors for achieving a high-quality image is to use clutter reduction techniques so that clutter as well as false target detection can be minimized. Therefore, in this paper, an attempt has been made to develop a clutter reduction technique for TWI in the UWB range for target detection. For this purpose, an experiment has been carried out with a TWI system in the UWB range for determination of the target position and size along with the development of the signal processing technique to minimize the clutter. A singular value decomposition (SVD) algorithm has been applied for clutter reduction. Encouraging results have been obtained from a metallic target behind a plywood wall of thickness 12 mm and a brick wall of thickness 110 mm. Application of the SVD approach provides a powerful technique for minimizing clutter and false detection for the TWI system in the UWB range. The position of the target behind the wall is predicted quite accurately by taking into account the propagation speed of waves through-walls. The approximate size of the target is also predicted successfully.