Detection of cracks on tomatoes using a hyperspectral near-infrared reflectance imaging system

Sensors (Basel). 2014 Oct 10;14(10):18837-50. doi: 10.3390/s141018837.

Abstract

The objective of this study was to evaluate the use of hyperspectral near-infrared (NIR) reflectance imaging techniques for detecting cuticle cracks on tomatoes. A hyperspectral NIR reflectance imaging system that analyzed the spectral region of 1000-1700 nm was used to obtain hyperspectral reflectance images of 224 tomatoes: 112 with and 112 without cracks along the stem-scar region. The hyperspectral images were subjected to partial least square discriminant analysis (PLS-DA) to classify and detect cracks on the tomatoes. Two morphological features, roundness (R) and minimum-maximum distance (D), were calculated from the PLS-DA images to quantify the shape of the stem scar. Linear discriminant analysis (LDA) and a support vector machine (SVM) were then used to classify R and D. The results revealed 94.6% and 96.4% accuracy for classifications made using LDA and SVM, respectively, for tomatoes with and without crack defects. These data suggest that the hyperspectral near-infrared reflectance imaging system, in addition to traditional NIR spectroscopy-based methods, could potentially be used to detect crack defects on tomatoes and perform quality assessments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Discriminant Analysis
  • Humans
  • Solanum lycopersicum / standards*
  • Spectroscopy, Near-Infrared / methods*
  • Support Vector Machine