Use of acoustic and stereo camera systems for assessing demersal fish of Robinson Crusoe Island (Juan Fernández Archipelago, off central Chile)

2017 ◽  
Vol 141 (5) ◽  
pp. 3865-3865
Author(s):  
Billy Ernst ◽  
Pablo Rivara ◽  
Braulio Tapia ◽  
Stephane Gauthier ◽  
Francisco Santa Cruz ◽  
...  
2021 ◽  
Vol 15 (03) ◽  
pp. 337-357
Author(s):  
Alexander Julian Golkowski ◽  
Marcus Handte ◽  
Peter Roch ◽  
Pedro J. Marrón

For many application areas such as autonomous navigation, the ability to accurately perceive the environment is essential. For this purpose, a wide variety of well-researched sensor systems are available that can be used to detect obstacles or navigation targets. Stereo cameras have emerged as a very versatile sensing technology in this regard due to their low hardware cost and high fidelity. Consequently, much work has been done to integrate them into mobile robots. However, the existing literature focuses on presenting the concepts and algorithms used to implement the desired robot functions on top of a given camera setup. As a result, the rationale and impact of choosing this camera setup are usually neither discussed nor described. Thus, when designing the stereo camera system for a mobile robot, there is not much general guidance beyond isolated setups that worked for a specific robot. To close the gap, this paper studies the impact of the physical setup of a stereo camera system in indoor environments. To do this, we present the results of an experimental analysis in which we use a given software setup to estimate the distance to an object while systematically changing the camera setup. Thereby, we vary the three main parameters of the physical camera setup, namely the angle and distance between the cameras as well as the field of view and a rather soft parameter, the resolution. Based on the results, we derive several guidelines on how to choose the parameters for an application.


2002 ◽  
Vol 14 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Cynthia Yau ◽  
Martin A. Collins ◽  
Phil M. Bagley ◽  
Inigo Everson ◽  
Imants G. Priede

The scavenging megafauna of the South Georgia and Shag Rocks slope in the south-west Atlantic (625–1519 m) were investigated using autonomous baited camera systems. Two surveys were conducted: the first in 1997 (13 deployments) used a conventional 35 mm stills camera with a 200 J flash, whilst the second in 2000 (15 deployments) used low-light digital video cameras. The scavenging community responded rapidly to the arrival of bait on the sea floor and was dominated by stone crabs (Lithodidae) and toothfish (Dissostichus eleginoides). Stone crabs took up residence around the bait until it was consumed, with a maximum number of 108 in the field of view after four hours. The most frequently observed crab species was Paralomis formosa. Paralomis spinosissima, Neolithodes diomedea and Lithodes sp., were also observed. Toothfish were the most frequently observed scavenging fish and were seen during all but one deployment, typically making brief visits (1–2 min) to the bait, but appeared startled by the flash in the 1997 survey. Labriform swimming (sculling with the pectoral fins) was the principal form of locomotion in toothfish (0.22 body lengths (BL) sec−1), but they were capable of more rapid sub-carangiform (using caudal trunk and fin) motion (3 BL sec−1) when startled. Other scavenging fish observed included the blue-hake Antimora rostrata, grenadiers (Macrourus spp.), skates, liparids and zoarcids.


Zootaxa ◽  
2018 ◽  
Vol 4402 (2) ◽  
pp. 373
Author(s):  
LUCAS R. P. GOMES ◽  
MÁRCIA S. COURI ◽  
CLAUDIO J. B. DE CARVALHO

Sixty years ago, Willi Hennig last catalogued the Anthomyiidae, Fanniidae and Muscidae fauna of the Juan Fernández Archipelago. This archipelago, composed of three main volcanic islands (Robinson Crusoe, Alejandro Selkirk and Santa Clara), has many endemic species. We describe Fannia hennigi sp. n. from the Robinson Crusoe Island, and record 11 species in 10 genera of Anthomyiidae, Fanniidae and Muscidae. A key to the identification of all species found in Juan Fernández Archipelago and a table with all species found in the Archipelago are presented, including four new records from Robinson Crusoe Island: Delia platura (Meigen, 1826); Fannia hennigi sp. n.; Lispoides insularis Hennig, 1957 and Schoenomyzina emdeni Hennig, 1955. 


2002 ◽  
Vol 56 (3) ◽  
pp. 263-284 ◽  
Author(s):  
Josef Greimler ◽  
Patricio Lopez S. ◽  
Tod F. Stuessy ◽  
Thomas Dirnbock

2011 ◽  
Vol 84 (3) ◽  
pp. 379-390 ◽  
Author(s):  
ÁLVARO T PALMA ◽  
ISMAEL CÁCERES-MONTENEGRO ◽  
RICHARD S BENNETT ◽  
SPARTACO MAGNOLFI ◽  
LUIS A HENRÍQUEZ ◽  
...  

Author(s):  
Shojiro Ishibashi ◽  
Hiroshi Yoshida ◽  
Tadahiro Hyakudome

The visual information is very important for the operation of an underwater vehicle such as a manned vehicle and a remotely operated vehicle (ROV). And it will be also essential for functions which should be applied to an autonomous underwater vehicle (AUV) for the next generation. Generally, it is got by optical sensors, and most underwater vehicles are equipped with various types of them. Above all, camera systems are applied as multiple units to the underwater vehicles. And they can construct a stereo camera system. In this paper, some new functions, which provide some type of visual information derived by the stereo vision system, are described. And methods to apply the visual information to the underwater vehicle and their utility are confirmed.


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