FN Archimer Export Format
PT J
TI Precision and accuracy of fish length measurements obtained with two visual underwater methods
BT 
AF ROCHET, Marie-Joelle
   CADIOU, Jean-Francois
   TRENKEL, Verena
AS 1:1;2:2;3:1;
FF 1:PDG-DOP-DCN-EMH;2:PDG-DOP-LER-LERPAC;3:PDG-DOP-DCN-EMH;
C1 IFREMER, Lab MAERHA, F-44311 Nantes 03, France.
   IFREMER, DNIS, SM IM, Ctr Mediterranee, F-83507 La Seyne Sur Mer, France.
C2 IFREMER, FRANCE
   IFREMER, FRANCE
SI NANTES
   TOULON
SE PDG-DOP-DCN-EMH
   PDG-DOP-LER-LERPAC
IN WOS Ifremer jusqu'en 2018
IF 1.403
TC 20
UR https://archimer.ifremer.fr/doc/2006/publication-978.pdf
LA English
DT Article
CR VITAL
BO L'Atalante
DE ;Auto focus method;Laser method;Error estimation;Measurement methods;Fish lenght
AB 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.
PY 2006
SO Fishery Bulletin
SN 0090-0656
PU NOAA Governmental fisheries science publications
VL 104
IS 1
UT 000234414700001
BP 1
EP 9
ID 978
ER

EF