Curve fitting using wavelet transform for resolving simulated overlapped spectra

Curve fitting must be considerably facilitated if reliable and accurate ini tial estimates of the number of peaks, individual peak positions, areas, an d widths are known at the outset. The most important values for input to cu rve fitting route are the number of peaks and their positions. One of the m ain drawbacks involved is that as the bands become more overlapped, or the number of overlapped bands increases, the problem becomes progressively mor e ill-conditioned. As a consequence, small errors in the data, or errors in the estimates can be magnified, ultimately resulting in large errors in th e final model. In addition, very high noise level of the analytical signal also has significant effect on the fitted results. In this work, curve fitt ing using wavelet transform for peak finding and an enhancement of signal-t o-noise ratio was proposed, in which wavelet transform was performed prior to curve fitting to enhance noise level for subsequent fitting and to deter mine the number of peaks and corresponding parameters. Accordingly, the fit ted conditions can be improved to the point that very accurate results coul d be acquired even for the simulated overlapped bands with higher noise lev el. (C) 2001 Elsevier Science B.V. All rights reserved.