基于EMD-自适应滤波的干涉图去噪方法研究

提出了一种基于EMD-自适应滤波干涉图去噪方法，该方法基于信号和噪声经过经验模态分解后在不同的IMF上有不同的特征，即先对信号进行经验模态分解，然后对各个高频IMF信号分别选用不同的滤波梯度参数进行自适应滤波处理，从初始干涉图上减去与斑点噪声所对应尺度信息，从而达到噪声抑制的目的。通过实验对比研究了该算法与Goldstein滤波、圆周期中值滤波、EMD分解方法和梯度-自适应滤波去噪的降噪效果。实验表明，该方法不仅能有效地去除InSAR干涉图的噪声，并且能很好地保持相位的细节信息和条纹的边缘信息。

The study of Interferogram denoising method Based on EMD and Adaptive Filter

A new adaptive filter based on empirical mode decomposition that is based on different characteristics of signal with noise in different IMFS for suppressing speckle in SAR interferogram is proposed. At first empirical mode decomposition is used to divide signal and processed high-frequency IMF signals separately by adaptive filter. The denoising effect of the proposed method, usual filter and multiscale EMD filter was investigated by experiment. When the part related to the speckle is subtracted from the original interferogram, the speckle noise is reduced. The result is compared with the four other methods of Goldstein filtering, periodic pivoting median filtering, EMD decomposition method and the adaptive filtering, and shows that EMD-adaptive filter method is powerful to interferogram speckle noise reduction, as well as it can preserve fine details in the interferogram that are directly related to the ground topography and maintain phase values distribution.