非均匀采样的傅里叶望远镜数值模拟研究  

Numerical Simulation of Fourier Telescopy Based on Non-Uniform Sampling

作　　者：于树海[1,2] 王建立[1] 董磊[1] 刘欣悦[1] 王国聪[1,2] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《光学学报》2013年第8期67-72,共6页Acta Optica Sinica

摘　　要：为了应用傅里叶望远镜(FT)技术对同步静止轨道和低轨运动卫星进行高分辨率成像探测,提出了一种基于非均匀采样技术,以低采样频率处理高频返回信息的新方法。对返回的时域信号进行非均匀采样并对数字信号进行离散非均匀傅里叶变换(NUDFT);衰减除高幅值低频信号以外的所有信号后再进行NUDFT即可精确地提取低频分量信息;重复幅值衰减和NUDFT直至提取所有的频率信息;通过相位闭合技术及传统重构方法即可重构目标。该方法降低了采样频率并克服了NUDFT方法的频谱噪声,有效地避免了高频噪声对成像质量的影响,特别是在低轨道多光束傅里叶望远镜成像方面有较大的应用前景。通过数值模拟验证了该方法的可行性,并在不同的信噪比条件下和传统均匀采样重构图像进行了对比研究,证实该方法对噪声的敏感程度与传统方法基本一致。In order to apply Fourier telescopy （FT） to the detection of synchronous geostationary orbit and low-earth orbit motion satellite and fulfill high-resolution imaging, a new method is proposed based on non-uniform sampling technology to achieve low sampling frequency for the high frequency information processing. Non-uniform sampling is made for the time domain returned signal into digital signal and the non-uniform discrete Fourier transform （NUDFT） is used. Amplitude damping is done to all the signals except the low-frequency signal and then the low frequency component information can be accurately extracted by the use of NUDFT. Amplitude damping and NUDFT are repeated until all the frequency information is extracted. The target can be constructed with phase closure techniques and traditional reconstruction method. This method reduces the sampling frequency, overcomes the spectral noise of the NUDFT method and avoids the influence of high-frequency noise on the imaging quality. It has bright application prospect, especially in low orbit multi-beam Fourier telescope imaging area. The feasibility of the method is verified by numerical simulation. Comparative researches are done for reconstruction image with the traditional uniform sampling result under different signal-to-noise ratios （SNRs）. The method is consistent on the noise sensitivity with traditional methods.

关 键 词：成像系统 傅里叶光学 图像重构 非均匀采样 幅值衰减 傅里叶望远镜 高分辨率成像 

分 类 号：V557[航空宇航科学与技术—人机与环境工程]