Detection of Rotten Citrus Fruit Using Fluorescent Images

Abstract

The fluorescent substances in citrus fruit peels were investigated by NMR analysis and excitation, and the fluorescence wavelengths of the substances were determined to develop a machine vision system that detects rotten citrus fruit. We concluded that the fluorescent substance in a mandarin orange was probably polymethoxylated flavone. Based on the results, we demonstrated the detection of the rotten parts on fluorescent images of mandarin oranges. From the experimental results of the fluorescence analysis of 14 varieties of citrus fruit, we observed that the peak wavelengths of the excitation and fluorescence of the extracted substance were 340 to 370 nm and 460 to 535 nm, respectively. The combination of UV-LED and color camera effectively detected the rotten parts of citrus peels.