Use of manned submersible and autonomous stereo-camera array to assess forage fish and associated subtidal habitat

2021 ◽  
Vol 243 ◽  
pp. 106067
Author(s):  
Matthew R. Baker ◽  
Kresimir Williams ◽  
H.G. Greene ◽  
Casey Greufe ◽  
Heather Lopes ◽  
...  
Keyword(s):  
Forage Fish ◽  
Stereo Camera ◽  
Subtidal Habitat ◽  
Camera Array ◽  
Manned Submersible

scholarly journals Equal Baseline Camera Array—Calibration, Testbed and Applications

2021 ◽  
Vol 11 (18) ◽  
pp. 8464
Author(s):  
Adam L. Kaczmarek ◽  
Bernhard Blaschitz
Keyword(s):  
Stereo Matching ◽  
Outdoor Environment ◽  
Learning Technology ◽  
Disparity Map ◽  
Stereo Camera ◽  
Camera Array ◽  
3D Data ◽  
Novel Approach ◽  
Calibration Methods ◽  
Wide Range

This paper presents research on 3D scanning by taking advantage of a camera array consisting of up to five adjacent cameras. Such an array makes it possible to make a disparity map with a higher precision than a stereo camera, however it preserves the advantages of a stereo camera such as a possibility to operate in wide range of distances and in highly illuminated areas. In an outdoor environment, the array is a competitive alternative to other 3D imaging equipment such as Structured-light 3D scanners or Light Detection and Ranging (LIDAR). The considered kinds of arrays are called Equal Baseline Camera Array (EBCA). This paper presents a novel approach to calibrating the array based on the use of self-calibration methods. This paper also introduces a testbed which makes it possible to develop new algorithms for obtaining 3D data from images taken by the array. The testbed was released under open-source. Moreover, this paper shows new results of using these arrays with different stereo matching algorithms including an algorithm based on a convolutional neural network and deep learning technology.

scholarly journals 3D Scanning of Semitransparent Amber with and without Inclusions

2021 ◽  
Author(s):  
Adam L. Kaczmarek ◽  
Jacek Lebiedź ◽  
Jakub Jaroszewicz ◽  
Wojciech Świeszkowski
Keyword(s):  
Virtual Reality ◽  
Structured Light ◽  
3D Structure ◽  
Laser Scanner ◽  
3D Scanning ◽  
Stereo Camera ◽  
Camera Array ◽  
Semitransparent Material ◽  
Structured Light Scanner ◽  
3D Scans

This paper is concerned with making 3D scans of semitransparent ambers with and without inclusions. The paper presents results of using a variety of devices applied for this purpose. Equipment used in the experiments includes a 3D laser scanner, a structured light scanner, a stereo camera, a camera array and a tomograph. The main object used in the experiment was an amber with a fossil of a lizard. The paper shows possibilities of acquiring the 3D structure of fossils embedded in semitransparent material which interfere with the measurement performed by 3D scanning equipment. Moreover, the paper shows the application of results of 3D scanning as the 3D scan of a lizard was reconstructed in a virtual reality cave making it possible to visualize in detail its shape and texture

Design of experimental food patches to measure foraging intensity for octopus: a case study with the giant Pacific octopus Enteroctopus dofleini

2020 ◽  
Author(s):  
Stephanie Chancellor ◽  
David Scheel ◽  
Joel S Brown
Keyword(s):  
Predation Risk ◽  
Foraging Behaviour ◽  
Habitat Preferences ◽  
High Tide ◽  
Intertidal Habitat ◽  
Camera System ◽  
Subtidal Habitat ◽  
Enteroctopus Dofleini ◽  
Nontarget Species

ABSTRACT In a study of the foraging behaviour of the giant Pacific octopus Enteroctopus dofleini, we designed two types of experimental food patches to measure habitat preferences and perceptions of predation risk. The first patch successfully measured giving-up densities (GUDs), confirmed by octopus prey presence and higher foraging at sites with historically greater octopus presence. However, nontarget foragers also foraged on these experimental food patches. Our second floating patch design successfully excluded nontarget species from subtidal patches, and from intertidal patches at high tide, but allowed for foraging by E. dofleini. The second design successfully measured GUDs and suggested that octopus preferred foraging in a subtidal habitat compared to an intertidal habitat. We ascribe the higher GUD in the intertidal habitat to its higher predation risk relative to the subtidal habitat. The second patch design seems well suited for E. dofleini and, in conjunction with a camera system, could be used to provide behavioural indicators of the octopus's abundance, perceptions of habitat quality and predation risk.

scholarly journals Experimental Research on the Process Parameters of a Novel Low-Load Drill Bit Used for 7000 m Bedrock Sampling Base on Manned Submersible

2021 ◽  
Vol 9 (6) ◽  
pp. 682
Author(s):  
Yu-Gang Ren ◽  
Lei Yang ◽  
Yan-Jun Liu ◽  
Bao-Hua Liu ◽  
Kai-Ben Yu ◽  
...  
Keyword(s):  
Deep Sea ◽  
Field Tests ◽  
Polycrystalline Diamond ◽  
Design Criterion ◽  
Penetration Length ◽  
Technical Data ◽  
Low Load ◽  
Manned Submersible ◽  
Rotary Speed ◽  
Cutting Model

Due to the need for accurate exploration of deep-sea scientific research, drilling techniques by combining the operational advantages of the Jiaolong manned submersible is considered one of the most feasible methods for deep-sea bedrock drilling. Based on deep sea bedrock cutting model and discrete element simulation, as well as efficient drilling as the design criterion, the development of a deep sea 7000 m electromechanical coring apparatus was carried out. The outstanding feature of this technology is that the bit load produced by the drill pressure is usually within the range 100–400 N while the recommended load for diamond drilling is 1–3 KN or even more. Therefore, searching for the drilling bits that can drill in extremely hard formations with minimal load and acceptable rates of penetration and rotary speed is the necessary step to prove the feasibility of electromechanical deep-sea drilling technology. A test has been designed and constructed to examine three types of drill bits. The results of experiments show that the new low-load polycrystalline diamond compact (PDC) bit has the highest penetration length of 138 mm/15 min under a 300 N load and 250 rpm rotary speed. Finally, field tests with the Jiaolong submersible were used to conduct deep sea experiments and verify the load model, which provides theoretical and technical data on the use of a low-load core sampling drill developed specifically for a deep sea submersible.

scholarly journals An empirical Bayesian approach to incorporate directional movement information from a forage fish into the Arnason-Schwarz mark-recapture model

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Mary A. Bishop ◽  
Jordan W. Bernard
Keyword(s):  
Bayesian Approach ◽  
Gulf Of Alaska ◽  
Forage Fish ◽  
Pacific Herring ◽  
Prince William Sound ◽  
Modeling Framework ◽  
Empirical Bayesian ◽  
Directional Information ◽  
Directional Movement ◽  
Empirical Bayesian Approach

Abstract Background Over the past two decades, various species of forage fish have been successfully implanted with miniaturized acoustic transmitters and subsequently monitored using stationary acoustic receivers. When acoustic receivers are configured in an array, information related to fish direction can potentially be determined, depending upon the number and relative orientation of the acoustic receivers. However, it can be difficult to incorporate directional information into frequentist mark-recapture methods. Here we show how an empirical Bayesian approach can be used to develop a model that incorporates directional movement information into the Arnason-Schwarz modeling framework to describe survival and migration patterns of a Pacific herring (Clupea pallasii) population in coastal Alaska, USA. Methods We acoustic-tagged 326 adult Pacific herring during April 2017 and 2018 while on their spawning grounds in Prince William Sound Alaska, USA. To monitor their movements, stationary acoustic receivers were deployed at strategic locations throughout the Sound. Receivers located at the major entrances to the Gulf of Alaska were arranged in parallel arrays to determine the directional movements of the fish. Informative priors were used to incorporate the directional information recorded at the entrance arrays into the model. Results A seasonal migratory pattern was found at one of Prince William Sound’s major entrances to the Gulf of Alaska. At this entrance, fish tended to enter the Gulf of Alaska during spring and summer after spawning and return to Prince William Sound during the fall and winter. Fish mortality was higher during spring and summer than fall and winter in both Prince William Sound and the Gulf of Alaska. Conclusions An empirical Bayesian modeling approach can be used to extend the Arnason-Schwarz modeling framework to incorporate directional information from acoustic arrays to estimate survival and characterize the timing and direction of migratory movements of forage fish.

Sign in / Sign up

Export Citation Format

Share Document