An improved signal determination method on machined surface topography

The characteristic signals of the machined surface are a mixture of actual signals and noise. It is feasible to make the features distinct through wavelet denoising. However, some of the deterministic signals may be lost with noise removed resulting in the loss of energy which make it difficult to judge the real components of the surface. An improved signal determination method -- wavelet denoising with compensation of the loss (WDCL) is proposed in this paper. The compensation method uses ensemble empirical mode decomposition (EEMD) and transfer function in which instantaneous frequency is calculated by Hilbert transform (HT). The coefficients of the transfer function are adjusted by improving the passing rate of the deterministic signals and lowering the passing rate of noise. The result shows that the WDCL can enhance the resolution of the real signals and reduce noise further.