Abstract: The approximation of a spectral continuum by determining a plurality of minima in the spectral data; splitting the spectral data into a predetermined number of groups N; for each group of spectral data, determining major minima for the group, and calculating an average and a standard deviation for the determined major minima; determining a polynomial function that can be drawn through the major minima of all groups; for each group of spectral data, determining minor minima; calculating an average deviation (?N) between this polynomial function and the determined minor minima; reducing the number of groups, and repeating this process for the reduced number of groups until a minimum number of groups is reached. Then, the least ?N corresponding to an optimal number of groups Nopt is determined. The spectral data is split into Nopt groups; and a polynomial function that can be drawn through both the major minima and minor minima is determined for Nopt groups.

Abstract: The present invention approximates and automatically subtracts continuum backgrounds in laser-induced breakdown (LIBS) and Raman spectra measured by non-gated detectors. Significantly, reference spectra are not used to determine background positioning in the present invention.