中文摘要：

提出采用小波变换进行返回散射电离图前沿的提取的方法；介绍基于小波变换边缘检测的原理及用于边缘检测小波基的选取原则，并对用于前沿提取的阈值确定首次采用归一化的方法降低了阈值选取难度。在有噪声存在的情况下，采用基于小波变换的边缘提取方法可有效的降低噪声的影响，实现返回散射电离图前沿的成功提取。

英文摘要：

Using wavelet transform to extract backscatter ionogram leading edges. In this thesis, we briefly introduce the principle of edge detection based wavelet transform and the standard choice of wavelet basis using edge detection. First put forward the normalized method to deal with the threshold determine using extracting backscatter ionogram leading. The algorithm of edge detection based wavelet transform can effectively deal with noisy images and achieve the extraction of Backscatter ionogram Leading edges.