Abstract: This paper introduces the basic theory and algorithm process of de-noising based on wavelet threshold and tanslation-invariant.On the base of traditional soft and hard threshold function，a new threshold function is made.This new threshold function is not only get over the disadvantage of hard threshold with discontinuous，but also solves the problem of the permanent bias in soft threshold function.It gets better effect when puts the new threshold function into the improved tanslation-invariant wavelet de-noising algorithm.

Key words: steel wire, wavelet threshold de-noising, threshold function, tanslation-invariant

摘要： 介绍了小波阈值去躁和平移不变量小波阈值去躁的基本原理及算法流程。在传统软硬阈值函数的基础上，构造了一个新的阈值函数，该阈值函数不仅克服了硬阈函数不连续的缺点，而且解决了软阈值函数存在的恒定偏差。将新阈值函数用于改进的平移不变量小波阈值去躁算法，取得了较好的降噪效果。

关键词: 钢丝绳, 小波阈值去噪, 阈值函数, 平移不变