Detecting internal insect infestation in tart cherry using transmittance spectroscopy

Abstract

This paper introduces an application of using transmittance spectroscopy to identify the infestation in tart cherry resulting from past or present insect activities. The spectra were recorded within a wavelength region between 550 and 980 nm with a FieldSpec spectroradiometer. The fresh tart cherries were hand harvested from different orchards in Michigan in 2004–2007. The samples included intact as well as infested cherries with different damage levels. The spectral analysis indicates that the maturity of tart cherry has effects on the classification accuracy. The intact cherries harvested late in the season (over-ripened) have similar spectral characteristics as the infested tissues. The classification accuracy for the samples harvested at normal time is better than that for the late harvested samples. Depending on the arrangement of the samples into non-infested or infested classes, the total classification accuracy varies from 82% to 87%. These findings and results demonstrate that transmittance spectroscopy has strong potential to detect the internal insect infestation within a tart cherry fruit.