Human is one kind of the most interesting targets in through-the-wall imaging. In high-resolution imaging applications, human is\nno longer a point target. Therefore, the previous signal models constructed by point target assumption cannot accurately describe\nreal characteristics of EM propagation. We construct the signal models based on extended target theory in this paper. Compared\nwith previous works, the main contributions are as follows. Firstly, human is considered as an extended target. The expressions\nof target scattering and wall reflections are derived. Secondly, target scattering is no longer isotropic in new model. A new kind\nof ghost problem which is caused by target obscuring in EM propagation is discovered and exploited. Thirdly, to improve image\nquality in moving target imaging, an efficient approach which adopts CFAR, clustering method, and spatial geometry relationship is\nproposed to remove the ghosts. The derived models are shown to agree with synthetic and experimental results. And the efficiency\nof proposed method is also validated,which illuminates that the ghosts are efficientlymitigated and the image quality is significantly\nimproved.
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