Use of a Gram-Schmidt response function in infrared microspectroscopic imaging

Abstract

The technique of infrared microspectroscopic imaging has found application in a variety of fields including coating technology, semiconductor manufacturing, and polymer science. The typical infrared microspectroscopic imaging experiment consists of collection of a four dimensional array of data (X, Y, frequency, intensity) followed by data reduction. In previous reports, this data reduction to three dimensions has been performed by monitoring the intensity or peak area of a specific frequency in the final transformed spectrum. This technique has been referred to as Functional Group Imaging (FGI).This paper reports on the application of an interferograms based data reduction routine to infrared microspectroscopic imaging. The Gram-Schmidt (GS) orthogonalization procedure, popularized in application to GC-IR data, was used to measure the infrared response across the surface of the samples. The details of the vector algebra used in the GS calculations may be found elsewhere. Briefly, a set of interferogram segments is selected to form an orthonormalized basis set describing background conditions.