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微波凝视成像作为一种新的成像模式,依靠多个相互独立的天线阵元发射随机信号,在空间形成时空两维随机辐射场,将回波信号形成的辐射场与预存的随机辐射场进行关联处理,从而实现成像。由于电磁信号在空间形成的辐射场具有很强的相关性,因此在进行直接关联处理后,得到图像的副瓣很高。本文针对上述问题提出对预存辐射场分别进行Schmidt及Bj?rck-Schmidt正交化处理,减小了邻近单元散射电磁信号的相关性,从而抑制了目标的副瓣,图像的信噪比得到提高,最终获得良好聚焦的图像。文中给出了直接关联处理及Schmidt和Bj?rck-Schmidt两种正交化方法性能的对比,同时对预存辐射场正交化处理后的信号特性进行了分析。仿真实验证明了Bj?rck-Schmidt正交化方法可以明显降低目标的副瓣,进而说明了该方法的有效性。
As a new imaging mode, microwave gaze imaging relies on a number of independent antenna elements to transmit random signals to form a space-time two-dimensional random radiation field in space, which associates the radiation field formed by the echo signal with the pre-stored stochastic radiation field Processing, in order to achieve imaging. Due to the strong correlation between the electromagnetic field and the radiation field formed by the electromagnetic signals, the side lobes of the image obtained after the direct correlation processing are very high. In view of the above problems, this paper proposes Schmidt and Bj? Rck-Schmidt orthogonalization for the stored radiation field respectively to reduce the correlation of the scattered electromagnetic signals of neighboring cells and suppress the side lobes of the target, thus improving the signal to noise ratio of the image , Finally get a good focus of the image. In this paper, we compare the performance of direct correlation processing and Schmidt and Bjöck-Schmidt orthogonal methods, and analyze the signal characteristics of the orthogonalized pre-stored radiation field. Simulation results show that the Bj? Rck-Schmidt orthogonalization method can significantly reduce the target sidelobe, and then demonstrate the effectiveness of the method.