Data/hora: 16/06/2024 11:29:10

Provedor de dados: 	5	
País: 	France	
Título: 	Precision and accuracy of fish length measurements obtained with two visual underwater methods	
Autores: 	Rochet, Marie-joelle; Cadiou, Jean-francois; Trenkel, Verena.	
Data: 	2006	
Ano: 	2006	
Palavras-chave: 	Auto focus method; Laser method; Error estimation; Measurement methods; Fish lenght.	
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.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/2006/publication-978.pdf

http://archimer.ifremer.fr/doc/00000/978/	
Editor: 	NOAA Governmental fisheries science publications	
Formato: 	application/pdf	
Fonte: 	Fishery Bulletin (0090-0656) (NOAA Governmental fisheries science publications), 2006 , Vol. 104 , N. 1 , P. 1-9	
Fonte: 	United States government publication free from any copyright restrictions

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