Reverse Intensity Correction for Raman Spectral Library Search.

A reverse intensity correction method was developed for spectral library searches to correct for instrument response without the side effect of magnifying the noise in the low responsivity region of test spectra. Instead of applying relative intensity correction to the sample test spectra to match the standardized library spectra, a reverse intensity correction is applied to the standardized library spectra to match the uncorrected sample spectrum. This simple procedural change improves library search performance, especially for dispersive charge-coupled device Raman analyzers using near-infrared excitations, where the instrument response often varies greatly across the spectral range, and signal-to-noise ratio in the low responsivity regions is typically poor.