Automatic nematode detection in cod fillets (Gadus morhua) by transillumination hyperspectral imaging

Abstract

Traditional quality control of cod fillets is currently made by manual inspection on candling tables. This is a time consuming and expensive operation, contributing to a significant share of the cost with cod fillet production. In this study, transillumination hyperspectral imaging was implemented as a method for automatic nematode detection in cod fillets moving on a conveyer belt, and evaluated on industrially processed cod fillets. An overall detection rate of 58% of all nematodes (N= 922), with detection rate of 71% and 46% for dark and pale nematodes, respectively, is reported. This is comparable, or better, than what is reported for manual inspection under industrial conditions. The false alarm rate was high, with 60% of the fillets reported with one or more false alarms. These results show that the method is promising, but needs further refinements to reduce the false alarm rate and increase the imaging speed from 25 to 400 mm/s. Practical Application: Manual inspection of cod fillets is a huge bottleneck for the industry, accounting for half the production cost with cod fillet processing and reducing the processing speed. Transillumination hyperspectral imaging has the potential to reduce the manual labor required for cod fillet inspection and hence reduce the cost and increase the end product quality.