Denoising of Fraunhofer Diffraction Signal Based on Wavelet Analysis

The diffraction methods were used to measure thin wires or fibers with some advantages. The method was based on Fraunhofer diffraction principle. The diffraction pattern can be detected by the Charge Coupled Device (CCD). CCD often produced the noise in the diffraction pattern and gave rise to the measuring error for the ambient disturbance. After theoretical simulation and analysis, the wavelet analysis was prior to the FFT method. The five repetition measurements of the diffraction pattern signals of the normal fiber were obtained. The five repetition measuring results showed that the wavelet analysis method was better than the FFT method to remove the noise from the signal. The diameter of the cotton fibers can assess the cotton´s qualities, so this research was very advantageous to the next study about the diameter measurement of the cotton fiber.