Patent ID: 7127372

Claim:
A method for improving regression-based spectroscopic analysis, comprising: a. computing a residual error between an estimated spectrum and a measured spectrum taken of a sample of a solid, liquid or gas substance to be analyzed using spectroscopy techniques, wherein the estimated spectrum is derived from mixing coefficients for members of a library spectra that are produced by computing a regression on the measured spectrum with the library spectra; b. identifying peaks in the residual error that extend in a direction opposite to that of peaks in the measured spectrum; c. performing a regression on the peaks in the residual error that extend in a direction opposite to that of the peaks in the measured spectrum to produce retro-regression coefficients; d. computing corrected mixing coefficients based on the retro-regression coefficients by subtracting the retro-regression coefficients from the mixing coefficients for the estimated spectrum for a current iteration; e. repeating (a) through (d) with the corrected mixing coefficients computed in (d) being used to generate a new estimated spectrum for computing the residual error in (a) at the next iteration; and f. determining whether a chemical or biological constituent whose spectra is contained in said library spectra is present in said sample based on said new estimated spectrum.