Hyperspectral vision in fish
In the production of fish, it is important to know the date of capture to know which product has to go to market earlier, thus guaranteeing its freshness.
The variation in natural pigmentation in fish according to its date of capture and method of conservation is considerable. The main one is seen in the colour of the eyes, varying the luminosity from black to translucent white during the initial period of 2 to 8 days. The eyes colour changes with the days during its conservation in the ice.
The main colour change in the fillets occurs during storage, increasing the yellowing. This change can be detected by analysing the colour in the frequency spectrum of the shades from blue to yellow. Gill filaments also show a characteristic change from bright red to pale yellow over time.
Currently, to determine the freshness of the fish is only available with information from fishing boats, which is not always accurate and can be fraudulent.
Through the analysis of hyperspectral images, we obtain information quickly, safely and not destructively for the evaluation of freshness, analyzing different parameters of the fish, which allows us to discriminate between varieties of the same and estimate the date of capture.
The great potential of colour analysis by hyperspectral imaging to evaluate the freshness of fish at its earliest age (up to about 10 days), solves a problem for producers, since it is not easy to evaluate the freshness quality of the fish by analytical means.