Detection of defect on navel orange using hyperspectral reflectance image

A hyperspectral imaging system for detecting defect on navel orange was demonstrated. The hyperspectral imaging system, which was a line-scan imaging system, consisted of a hyperspectral camera, a halogen lighting unit, a computer and a translation stage. The imaging system operated from 400 to 1000nm. Principal component analysis (PCA) was performed using the hyperspectral images data (from 500 to 700nm); 2nd principal component (PC) image exhibited differential responses between normal and defect spots on the surface of navel orange. The combined use of the PC-2 images demonstrated the detection of defect spots with minimal false positives. Based on the PC-2 weighing coefficients, the dominant wavelengths were 528,529,530,673,674 and 675nm. This research demonstrated the potential of multispectral image for online applications for detection of defect on navel oranges.