Methods for measuring the three-dimensional structure of fish schools

Cullen, J. M.; Shaw, Evelyn; Baldwin, Howard A.

doi:10.1016/0003-3472(65)90117-x

Cited by 117 publications

(62 citation statements)

References 4 publications

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“…Cullen et al, 1965;Pitcher, 1975;Dill et al, 1981) or bird flocks (Major & Dill, 1978). The accuracy in these studies is as high as 50.3 to 3.5% of the measured distances, and is attained by the use of sophisticated equipment and calibration techniques, usually under laboratory conditions.…”

Section: Introductionmentioning

confidence: 99%

A simple field method for stereo-photographic length measurement of free-swimming fish: merits and constraints

Rooij

Videler

1996

Journal of Experimental Marine Biology and Ecology

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A simple field method to correct for bias in stereo-photographic underwater measurements is presented and its usefulness to improve the accuracy of length estimates of free-swimming fish is tested. The calibration is based on the inclusion of stereo exposures of a slate of known dimensions at the beginning and end of each measuring session. and it allows correction for non-parallel optical axes, spherical aberration of the lenses. and for other sources of bias that may vary between sessions. A precision of t3% for replicate length measurements of a 30 cm slate is obtained at distances between 0.7 and 2.0 m. This compares well with reported values that are obtained with more sophisticated (laboratory) methods.However, application of this calibration does not significantly improve the accuracy of stereo measurements of the length of free-swimming fish (22.5 cm or 7-11% of actual fish length). The limitations are caused by difficulties in recognizing identical extreme points at the body of fish that are photographed under field conditions. By averaging three or more replicate measurements the accuracy is improved to il cm (2.7-4.5%).We conclude that effort should be aimed at increasing sample size. rather than at improving equipment and correction procedures, when measuring free-swimming fish in their natural habitat.

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Section: Introductionmentioning

confidence: 99%

A simple field method for stereo-photographic length measurement of free-swimming fish: merits and constraints

Rooij

Videler

1996

Journal of Experimental Marine Biology and Ecology

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“…As in terrestrial ecology, stereophotography enables reference-free and non-invasive measurements of object coordinates in the 3D realm, thus eliminating the need for a parallel estimation of quantitative parameters such as distance or volume (e.g. Cullen et al, 1965;Rorslett et al, 1978;Van Rooij and Videler, 1996;Costa et al, 2006;Williams et al, 2010). Photographic assessments of time series of communities also allow the estimation of quantitative derivatives, including growth or productivity over time, using an empirically determined relationship between biomass and linear measurements (Williams, 1969;Rorslett et al, 1978;Fischer et al, 2007;Williams et al, 2010, Doya et al, 2014.…”

Section: Introductionmentioning

confidence: 99%

“…A range of other marine biology applications also routinely use stereoimaging techniques (photo as well as video), including: fish monitoring (Ruff et al, 1995;Van Rooij et al, 1995;Li et al, 1996;Tillett et al, 2000;Harvey et al, 2003;Costa et al, 2006;Costa et al, 2009;Rooper et al, 2010;Bower et al, 2011;Torisawa et al, 2011); determination of the 3D structure of fish schools (Cullen et al, 1965;Pitcher, 1975;Dill et al, 1981;Sawada et al, 2009); determination of the influence of substrate complexity on the interaction between fish and the artificial substrate (Fischer et al, 2007); and surveys of the benthos and the sea floor (Emerey et al, 1965;Evans and Norris, 1997;Chong and Stratford, 2002;Jasiobedzki et al, 2008;Shortis et al, 2008;Svane et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

A practical guide to the use of consumer-level digital still cameras for precise stereogrammetric <I>in situ</I> assessments in aquatic environments

Wehkamp¹,

Fischer²

2014

uw tech: int j soc uw tech

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Scientists planning to use underwater stereoscopic image technologies are often faced with numerous problems during the methodological implementations: commercial equipment is too expensive; the setup or calibration is too complex; or the imaging processing (i.e. measuring objects in the stereo-images) is too complicated to be performed without a time-consuming phase of training and evaluation. The present paper addresses some of these problems and describes a workflow for stereoscopic measurements for marine biologists. It also provides instructions on how to assemble an underwater stereo-photographic system with two digital consumer cameras and gives step-by-step guidelines for setting up the hardware. The second part details a software procedure to correct stereo-image pairs for lens distortions, which is especially important when using cameras with non-calibrated optical units. The final part presents a guide to the process of measuring the lengths (or distances) of objects in stereoscopic image pairs. To reveal the applicability and the restrictions of the described systems and to test the effects of different types of camera (a compact camera and an SLR type), experiments were performed to determine the precision and accuracy of two generic stereo-imaging units: a diver-operated system based on two Olympus Mju 1030SW compact cameras and a cable-connected observatory system based on two Canon 1100D SLR cameras. In the simplest setup without any correction for lens distortion, the low-budget Olympus Mju 1030SW system achieved mean accuracy errors (percentage deviation of a measurement from the object's real size) between 10.2 and -7.6% (overall mean value: -0.6%), depending on the size, orientation and distance of the measured object from the camera. With the single lens reflex (SLR) system, very similar values between 10.1% and -3.4% (overall mean value: -1.2%) were observed. Correction of the lens distortion significantly improved the mean accuracy errors of either system. Even more, system precision (spread of the accuracy) improved significantly in both systems. Neither the use of a wide-angle converter nor multiple reassembly of the system had a significant negative effect on the results. The study shows that underwater stereophotography, independent of the system, has a high potential for robust and non-destructive in situ sampling and can be used without prior specialist training.

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“…Tu and Terzopoulos [5] developed more realistic simulated fish schooling by accurately modeling the animals' muscle and behavioral systems. Brogan and Hodgins [6] developed a system for realistically animating herds of one-legged agents using dynamical models of robot motion.…”

Section: Modeling Of Flocking Behaviormentioning

confidence: 99%

“…Parker simulates robots in a line-abreast formation navigating past waypoints to a final destination [15]. The agents are programmed using the layered subsumption architecture [5]. Parker evaluates the benefits of varying degrees of global knowledge in terms of cumulative position error and time to complete the task.…”

Section: Modeling Of Flocking Behaviormentioning

confidence: 99%

Massive Multi-Agent Simulation in 3D

Aoyagi

Namatame

Advances in Soft Computing

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Abstract:In this paper, we discuss our challenge on how to give the creatures and ability to follow spatial restriction while keeping the complexity low enough to still allow for real-time simulation of the herd. Our methodologies extend the pioneering work by Reynolds' flocking algorithm. We extend how the herd can move in natural-looking paths. Also, we show like the creatures to travel smoothly in 3D space with speed regulation in curve.

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Methods for measuring the three-dimensional structure of fish schools

Cited by 117 publications

References 4 publications

A simple field method for stereo-photographic length measurement of free-swimming fish: merits and constraints

A simple field method for stereo-photographic length measurement of free-swimming fish: merits and constraints

A practical guide to the use of consumer-level digital still cameras for precise stereogrammetric <I>in situ</I> assessments in aquatic environments

Massive Multi-Agent Simulation in 3D

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