Nondestructive Detection of Internal Insect Infestation in Jujubes Using Visible andNear-Infrared Spectroscopy

Abstract

This paper reports on a study of comparing three spectroscopic measurements (i.e., interactance, reflectance, and transmittance) in the Vis/NIR range for the detection of internal insect infestation with different damaged levels in jujubes. The stepwise discriminant analysis was used to derive the discriminant functions based on the effective wave lengths that had maximum discriminatory potential for the different internal conditions. The results show both of the interactance in the long-wave NIR (LWNIR) and the transmission in the visible and short-wave near-infrared (VSWNIR) wavelength ranges display an obvious advantage over the reflectance for every range in completely distinguishing infested jujubes from intact jujubes; however, interactance and reflectance in the VSWNIR wavelength range exhibited higher classification accuracies in sorting severely damaged jujubes from slightly infested and intact samples; furthermore, transmission had clear advantages over both interactance and reflectance for distinguishing slightly infested jujubes from intact jujubes in the VSWNIR range.