| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Precision and accuracy of fish length measurements obtained with two visual underwater methods
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| Autores: |
Rochet, Marie-joelle
Cadiou, Jean-francois
Trenkel, Verena
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| Data: |
2006
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| Ano: |
2006
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| Palavras-chave: |
Auto focus method
Laser method
Error estimation
Measurement methods
Fish lenght
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| Resumo: |
During the VIITAL cruise in the Bay of Biscay in summer 2002, two devices for measuring the length of swimming fish were tested: 1) a mechanical crown that emitted a pair of parallel laser beams and that was mounted on the main camera and 2) an underwater auto-focus video camera. The precision and accuracy of these devices were compared and the various sources of measurement errors were estimated by repeatedly measuring fixed and mobile objects and live fish. It was found that fish mobility is the main source of error for these devices because they require that the objects to be measured are perpendicular to the field of vision. The best performance was obtained with the laser method where a video-replay of laser spots (projected on fish bodies) carrying real-time size information was used. The auto-focus system performed poorly because of a delay in obtaining focus and because of some technical problems.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/2006/publication-978.pdf
http://archimer.ifremer.fr/doc/00000/978/
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| Editor: |
NOAA Governmental fisheries science publications
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| Formato: |
application/pdf
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| Fonte: |
Fishery Bulletin (0090-0656) (NOAA Governmental fisheries science publications), 2006 , Vol. 104 , N. 1 , P. 1-9
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| Direitos: |
United States government publication free from any copyright restrictions
info:eu-repo/semantics/openAccess
restricted use
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