Dual imaging technique for a real-time inspection system of foreign object detection in fresh-cut vegetables

Authors: KURNIAWANA, HARY - Chungnam National University; ARIEFA, MUHAMMAD - Chungnam National University; SANTOSH, LOHUMI - Chungnam National University; Kim, Moon; Baek, Insuck; CHO, BYOUNG-KWAN - Chungnam National University

Submitted to: Current Research in Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2024
Publication Date: 7/5/2024
Citation: Kurniawana, H., Ariefa, M., Santosh, L., Kim, M.S., Baek, I., Cho, B. 2024. Dual imaging technique for a real-time inspection system of foreign object detection in fresh-cut vegetables. Current Research in Food Science. 9: article 100802. https://doi.org/10.1016/j.crfs.2024.100802.
DOI: https://doi.org/10.1016/j.crfs.2024.100802

Interpretive Summary: Fresh-cut vegetables sold in retail stores are expected to be clean and free from foreign materials such as plastic or metal. However, these small foreign materials can sometimes infiltrate the products, posing health risks. In this research, a dual-camera imaging system was developed to detect foreign objects in fresh-cut vegetables. One camera captures standard color images while the second camera coupled with UV light captures fluorescence images from the samples. As the fresh-cut vegetables move along a conveyor belt, both cameras operate simultaneously to detect foreign materials in real-time. The results demonstrated that the dual imaging technique can effectively detect foreign materials with high accuracies in two types of fresh-cut vegetables studied in this investigation. This technology can potentially be used to aid the fresh-cut processing facilities to ensure the fresh-cut vegetable products are free of foreign materials and safe for consumption.

Technical Abstract: Fresh-cut vegetables are a food product susceptible to contamination by foreign materials (FMs). To detect a range of potential FMs in fresh-cut vegetables, a dual imaging technique (fluorescence and color imaging) with a simple and effective image processing algorithm in a user-friendly software interface was developed for a real-time inspection system. The inspection system consisted of feeding and sensing units, including two cameras positioned in parallel, illuminations (white LED and UV light), and a conveyor unit. A camera equipped with a long-pass filter was used to collect fluorescence images. Another camera collected color images of fresh-cut vegetables and FMs. The feeding unit fed FMs mixed with fresh-cut vegetables onto a conveyor belt. Two cameras synchronized programmatically in the software interface simultaneously collected fluorescence and color image samples based on the region of interest as they moved through the conveyor belt. Using simple image processing algorithms, FMs could be detected and depicted in two different image windows. The results demonstrated that the dual imaging technique can effectively detect potential FMs in two types of fresh-cut vegetables (cabbage and green onion), as indicated by the combined accuracy of both fluorescence and color imaging. The test results showed that the real-time inspection system could detect FMs measuring 0.5 mm in fresh-cut vegetables. The results showed that the combined detection accuracy of FMs in the cabbage (95.77%) sample was superior to that of green onion samples (87.89%). Therefore, the inspection system was more effective at detecting FMs in cabbage samples than in green onion samples.