In this paper, we proposed an adaptive threshold de-noising method by combining wavelet entropy and inter-scale correlation. Different from the traditional wavelet threshold based de-noising methods, our method can be divided into three steps. First, we decompose the noisy signal by using discrete wavelet transform (DWT), calculate the value of inter-scale correlation of the decomposed wavelet coefficients, and delete the high frequency coefficients which are smaller than the value of inter-scale correlation. Secondly, we equally divide the pro...