在穿墙雷达成像领域，建筑墙体会改变电磁波的传播路径和速度，引入目标散射回波延迟误差，造成隐蔽目标成像散焦、位置偏移和多径幻象等。对此提出一种墙体补偿技术，准确计算像素点与天线之间的聚焦延时，修正目标图像位置偏移和散焦等，实现聚焦目标图像。首先，对回波数据采用后向投影成像算法，得到原始图像。其次，利用 Radon 变换，并结合图像连通域检测得到墙体前后表面的位置。最后，通过计算墙体前后表面距离，得到约束条件；在该条件下，假定墙体厚度和介电常数，对墙后目标进行补偿成像。Matlab 仿真数据验证了该算法的有效性。%With respect to through-wall-radar imaging,the ambiguities in wall characteristics including thickness and relative permittivity will change the speed and propagation path of electromagnetic wave.These changes will defocus the target image and displace the target away from its true position.A new algorithm is proposed to solve these problems.Though calculating focus delay from the pixel to the antenna accurately, we can correct target image position and focus the target image.Firstly,back-projection imaging algorithm is adopted to obtain the original image.Secondly,the Radon transformation and depth-first-searching algorithm are used to detect the position of wall.Finally,a constraint is got by calculating the distance between the front surface and the back surface of the wall.Under this condition,a couple of assumed wall parameters is adopted to from the focusing target image.
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