Label-free technology for traceable identification of single green pepper through features in UV fluorescent images

• Published in: Computers and electronics in agriculture 2023-08, Vol.211, p.107960, Article 107960
• Main Authors: Takemoto, Tetsuyuki, Huang, Zichen, Omwange, Ken Abamba, Saito, Yoshito, Konagaya, Keiji, Suzuki, Tetsuhito, Ogawa, Yuichi, Kondo, Naoshi
• Format: Article
• Language: English
• Subjects: Feature points; Fluorescence images; Green pepper; Label-free; Traceable identification
• ISSN: 0168-1699; 1872-7107
• DOI: 10.1016/j.compag.2023.107960

•Unique features under UV light were captured.•Experiments were conducted to evaluate the proposed matching algorithm.•The success rate of single pepper tracing reached 81.3 %.•A label-free technology for tracing single green pepper in one package. In the food supply chain, vegetable traceability holds significant importance. Conventional methods for traceability rely on tag-based systems such as barcodes, QR codes, or RFID tags. However, these methods face challenges when it comes to tracing single vegetables, such as green peppers between the grading facility and greenhouse harvesting. Unlike fruits like melons and watermelons, green peppers lack visible unique features on their surface that can be used to identify individual vegetables. Through our research, we have discovered that the fluorescence images of green peppers display a unique texture on the surface, which provides the possibility of identifying single green pepper. We proposed a single pepper traceable method that combines pepper images from the greenhouse and postharvest stage under UV light using imaging features. Our experiments aimed to evaluate the method's performance, including feature description, tracing success rate, performance change with storage, and changes with different length of the green peppers. The results showed that the KAZE feature was suitable for describing the surface feature of a green pepper under UV light, achieving a feature-matching performance of 81.3 % success rate in tracking individual peppers in each of the 15 packages, each with 10 peppers, using images from the day after harvest and greenhouse images. Furthermore, the method's performance could be affected by the storage time and length of the peppers. The proposed method could be a cost-effective, accurate, and label-free method to achieve single green pepper level traceability in smart agriculture.