The accuracy and precision of underwater measurements of length and maximum body depth of southern bluefin tuna (Thunnus maccoyii) with a stereo–video camera system

Harvey, Euan S.; Cappo, Michael; Shortis, Mark R.; Robson, Stuart; Buchanan, J.; Speare, Peter

doi:10.1016/s0165-7836(03)00080-8

Cited by 160 publications

(116 citation statements)

References 4 publications

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“…With stereo video, two cameras are mounted on a calibrated frame and then synchronized to record the same object simultaneously (Mallet and Pelletier, 2014). These recordings give the observer highly accurate three-dimensional images, while collecting data on both flora and fauna unobtrusively (Harvey et al, 2003). This ability to observe without disturbance makes this method a valuable tool for studying mobile species such as fish.…”

Section: Camera Surveys and Assessment Of Fish Assemblagesmentioning

confidence: 99%

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Habitat Connectivity of Fish in Temperate Shallow-Water Seascapes

2018

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Movements of organisms comprise a fundamental aspect of coastal habitat connectivity. Determining the distribution and co-existence of habitat specialists and generalists in shallow-water seascapes leads to a better understanding of the strength of connectivity-driven community patterns in coastal areas. In this study, unbaited Remote Underwater Video (RUV) systems were used to examine habitat usage and connectivity of fish within six shallow-water coastal seascapes on the Swedish west coast. Within each seascape, video sampling was conducted at three different shallow-water habitats: seagrass meadows, rock-macroalgae and unvegetated areas, in June 2014. Comparative analyses showed that the shallow-water fish community was similar in adjacent habitats within a seascape, though abundances of fish were higher within the structurally complex habitats. All habitats were dominated by juveniles, highlighting the importance of the coastal seascape for early fish life stages. The findings demonstrate that adjacent shallow-water habitats in temperate coastal waters are linked through similar species utilization and that the coastal matrix could be regarded in terms of a seascape nursery for fish. The study highlights the importance of considering shallow-water seascape connectivity in coastal conservation planning and management.

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Section: Camera Surveys and Assessment Of Fish Assemblagesmentioning

confidence: 99%

“…seagis.com.au) analysis software, data was collected on species identification and abundance information, as well as the length of individuals (Harvey et al, 2001(Harvey et al, , 2002(Harvey et al, , 2003. All fish were identified to the lowest taxonomic level possible, counted, and measured.…”

Section: Camera Surveys and Assessment Of Fish Assemblagesmentioning

confidence: 99%

Habitat Connectivity of Fish in Temperate Shallow-Water Seascapes

2018

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“…Self calibration is also applied for the camera-housing system, where it is assumed that refraction effects are compensated by the interior orientation parameters (Shortis and Harvey, 1998;Gründig et al, 1999;Canciani et al, 2003;Harvey et al, 2003;Drap et al, 2007;Shortis et al, 2007b). However, when analyzing the correction of the image points, especially for close ranges, the distance of the object points from the camera severely affects the correction (Telem and Filin, 2010).…”

Section: Underwater Camera Calibrationmentioning

confidence: 99%

Camera Constant in the Case of Two Media Photogrammetry

Agrafiotis

Georgopoulos

2015

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Refraction is the main cause of geometric distortions in the case of two media photogrammetry. However, this effect cannot be compensated and corrected by a suitable camera calibration procedure (Georgopoulos and Agrafiotis, 2012). In addition, according to the literature (Lavest et al. 2000), when the camera is underwater, the effective focal length is approximately equal to that in the air multiplied by the refractive index of water. This ratio depends on the composition of the water (salinity, temperature, etc.) and usually ranges from 1.10 to 1.34. It seems, that in two media photogrammetry, the 1.33 factor used for clean water in underwater cases does not apply and the most probable relation of the effective camera constant to the one in air is depending of the percentages of air and water within the total camera-to-object distance. This paper examines this relation in detail, verifies it and develops it through the application of calibration methods using different test fields. In addition the current methodologies for underwater and two-media calibration are mentioned and the problem of two-media calibration is described and analysed.

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“…Application fields are the documentation of sunken objects like boat parts or ship wrecks (Korduan at al. 2003), the documentation of archaeological sites (Roman et al 2010), the surface measurement and inspection of industrial facilities such as pipeline systems (Tetlow et al 1999) or the measurement of biological objects such as fishes (Harvey et al 2003, Dunbrack 2006, Costa et al 2006 or coral reefs (Bythell et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Compact Handheld Fringe Projection Based Underwater 3d-Scanner

Bräuer-Burchardt

Heinze²,

Schmidt³

et al. 2015

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:A new, fringe projection based compact handheld 3D scanner for the surface reconstruction of measurement objects under water is introduced. The weight of the scanner is about 10 kg and can be used in a water depth of maximal 40 metres. A measurement field of about 250 mm x 200 mm is covered under water, and the lateral resolution of the measured object points is about 150 µm. Larger measurement objects can be digitized in a unique geometric model by merging subsequently recorded datasets. The recording time for one 3D scan is a third of a second. The projection unit for the structured illumination of the scene as well as the computer for device control and measurement data analysis are included into the scanners housing. A display on the backside of the device realizes the graphical presentation of the current measurement data. It allows the user to evaluate the quality of the measurement result in real-time already during the recording of the measurement under water. For the calibration of the underwater scanner a combined method of air-and water-calibration was developed which needs only a few recorded underwater images of a plane surface and an object with known lengths. First measurement results obtained with the new scanner are presented.

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The accuracy and precision of underwater measurements of length and maximum body depth of southern bluefin tuna (Thunnus maccoyii) with a stereo–video camera system

Cited by 160 publications

References 4 publications

Habitat Connectivity of Fish in Temperate Shallow-Water Seascapes

Habitat Connectivity of Fish in Temperate Shallow-Water Seascapes

Camera Constant in the Case of Two Media Photogrammetry

Compact Handheld Fringe Projection Based Underwater 3d-Scanner

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