Electromagnetic Sensor for Automatic Detection....
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GRANT NUMBER:  NA66FD0046           NMFS NUMBER:   95-AKR-012

REPORT TITLE: Electromagnetic Sensor for Automatic Detection of Parasites in Fish

AUTHOR: Choudhury, G.; Bublitz, C.G.; Jenks, W.G.; Ammons, D.E.; and Wikswo, Jr., J.P.

PUBLISH DATE:  May 29, 1997

AVAILABLE FROM:  National Marine Fisheries Service, P.O. Box 21668, Juneau, AK 99802-1668.  PHONE: (907) 586-7280


Candling, the traditional means of detecting parasites during fish fillet processing, is time consuming and labor intensive.  This method is a major factor in reducing the quality and increasing the cost of fish brought to market. The difference in electrical conductivity between fish and an embedded parasite was hypothesized to provide a practical basis for an instrument, which would have potential for automated parasite detection. In a previous experiment, a small electrical current was passed through a parasite-containing fillet and the magnetic field above the fillet was recorded by a Superconducting Quantum Interference Device (SQUID) magnetometer. The results indicated that the technique had promise as a means to detect parasites in an automated configuration. It was shown that the magnetic signature of a single parasite embedded in a small fillet could be detected under particular conditions. Here we report on an extension of that work which extends the experimental parameters into various frequency and signal regimes. It is shown here that the signal of interest is independent of the frequency of the injected current up to 2000 Hz and that the magnitude of the signal scales with current amplitude.

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