The Use of Trigonometric Polynomials to Approximate Visible and near Infrared Spectra of Agricultural Products

Abstract

A Fourier analysis of the spectra consisting of 1000 to 2000 reflectance values obtained by scanning agricultural products at specific, equally spaced wavelengths is used to reduce the amount of data that needs to be recorded. It is shown that as few as 50 pairs of coefficients retain the bulk of the information contained in the complete spectrum. Using the limited number of Fourier coefficients is equivalent to rejecting the high frequency noise without spectral distortion and loss of data points at the ends of the spectra.