Abstract：Wavelet analysis (WT) was conducted on the simulated near infrared spectra (NIR) obtained by adding simulated background and simulated noise into diesel NIR. Results show that the background components are mainly located in the low frequency region, while noise in the high frequency region, and useful signal in the middle frequency region. Background and noise components can be simultaneously subtracted from the spectra by WT. The WT coefficients in mid-frequency details can be selected as variables to build the multivariate calibration model, which can improve analytic accuracy and reduce the analysis time.
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