Application of wavelet transform in infrared spectrometry: spectral compression and library search

In recent years, a new mathematical technique called wavelet transform (WT) has been developed and adopted for signal processing in analytical chemist ry owing to its efficiency, more number of basis functions available, and h igher speed in data treatment compared to fast Fourier transform (FFT). In this paper, the fast wavelet transform (FWT) and its derivative, wavelet pa cket transform (WPT), were applied to compress infrared (IR) spectrum for s torage and spectral searching. In WT treatment, the number of data to be pr ocessed has to be 2(P) with P being any integer. In this work, we proposed the coefficient position retaining (CPR) method to handle data with length of odd number. The performance of the two proposed WT methods in data compr ession and spectral library searching are compared with that of the FFT met hod. The results indicated that our proposed WT methods works better than F FT in compression of IR spectra and spectral Library searching. (C) 1998 El sevier Science B.V. All rights reserved.