小波阈值法的改进及在地质雷达探测中的应用

隧道超前地质预报是否准确，高信噪比的地质雷达信号是关键。在进行地质雷达探测时，由于受到周围复杂环境的影响，采集的雷达数据中含有各种干扰信号，降低了信号质量，直接影响到解译人员对地质条件的解读，影响了隧道超前地质预报的精确度。因此，本工作提出利用一种优化过的阈值方法对信号进行去噪，提高信噪比。优化主要是从优化阈值选取方式和优化阈值函数的选取两个方面对软阈值方法进行优化，并且通过仿真实验进行验证。结果显示信噪比的提升和均方差的减小幅度上以及去噪效果三方面对比，实验证明改进方法更优于软硬阈值方法，改进方法可适用于实际雷达数据干扰信号的处理，能提高信号信噪比，更好的还原信号。

An improvement of the wavelet threshold method and its application to the detection by geological radar

Signal of geological radar with high signal to noise ratio is very important for precise forecast of tunnels under construction. In the geological radar detection, because of the complicated environment, the radar data collected contain various disturbances signals that reduce the signal quality, directly affecting the interpretation to geological conditions and the accuracy of tunnel geological prediction. To solve this problem, we propose to use an optimized threshold method to denoise the signal and improve the signal to noise ratio. From the two aspects of the ways to choose optimization threshold values and optimization threshold functions, we optimize the soft threshold method, and verify it by simulation experiments. We make comparison in enhancement of signal-to-noise ratio, reduction of mean square variance and the denoising effect. The results show that the improved method is better than the existing soft threshold method. It can be applied to processing of real radar data, raise the signal-to-noise ratio, and better recover the original signal.