Calibration transfer of near-infrared spectra based on compression of wavelet coefficients

Near-infrared (NIR) spectrometers are widely used as online analyzers. We propose a transfer algorithm of a calibration model for the near-infrared spectrometer. The method, which is based on direct standardization in the compressed wavelet domain, is called WTDS. Calibration transfer in the compressed wavelet domain permits a reduction in processing time for the analysis of large spectral data sets. A calibration transfer based on a compression of wavelet coefficients offers increased robustness against testing errors, with no significant loss of performance. We select the proper set of wavelet coefficients based on the hard thresholding approach. The WTDS shows an improvement in calibration transfer performance, although wavelet coefficients are compressed.