光纤熔接缺陷的超声检测中，由于受噪声干扰，一些弱结合缺陷很难被正确检测出来。在多分辨分析小波阈值去噪方法基础上，提出了一种改进的阈值函数，并将其应用于缺陷信号的去噪。实际缺陷信号去噪结果表明，该算法与传统方法相比，具有重建信号均方误差小，信噪比高的优点，具有很好的去噪效果。

In the ultrasonic testing to optical fiber fusion defect, because of the noise pollution, some weak bounding defect is difficult to detect. A modified threshold function based on the wavelet multi-resolution analysis threshold denoising method was proposed, and applied on defect signal denoising. The result of actual defect signal denosing showed that this method was of advantage to get less mean-squared error and high signal-to-noise ratio reconstruction signal therefore, which had excellent denoising result.