Patent ID: 7307257
Filing Date: 2007-12-11
Classification: G01N

Abstract:
1. A method for measuring a property of a test sample comprising: a) obtaining a set of measured spectra for a set of calibration samples, and performing constrained principal spectral analysis on said calibration samples to provide a corrected set of measured spectra, b) providing said test sample having an unknown value of said property, c) applying light to said test sample resulting in reflected light, d) detecting said reflected light, e) transmitting said reflected light to a spectrometer, f) measuring a spectrum for said test sample, g) performing constrained principal spectral analysis on said test sample spectrum to provide a corrected test sample spectrum, h) performing locally weighted regression analysis by selecting a subset of said corrected calibration sample spectra and building a regression model based upon said selected subset, and i) predicting a value for said unknown property of said test sample using said corrected test sample spectrum and said regression model.