Reducing the Effect of Noise for the Estimation of the Surface Profile in White Light Interference by Combining Both Fourier Transform and Wavelet Methods
摘要
White light interference (WLI) is a powerful technique that can be used to exactly measure the surface profile. In this technique, noise is a cause that leads to the inability to accurately measure the surface profiles. In this paper, we proposed a novel method based on the combination of the Fourier transfer method and the Wavelet method to reduce the effect of noise over the estimation result of the surface profile in WLI. This combination has two steps. The first step, the fast Fourier transfer (FFT) will be used to remove a noise part in the interference pattern along z diction. The next step, the continues Wavelet transform (CWT) method will be continuously used to remove a noise part and to determine the surface profile. The simulation results demonstrated that the proposed method can be employed to increase the accuracy of WLI under the corruption of noises in comparison with both FFT and CWT methods.