A 3D stereo camera system for precisely positioning animals in space and time

Macfarlane, Nicholas; Howland, Jonathan C.; Jensen, Frants H.; Tyack, Peter L.

doi:10.1007/s00265-015-1890-4

Cited by 10 publications

(6 citation statements)

References 36 publications

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“…Despite the difficulties associated with observing wild delphinids, photogrammetry using unmanned aerial vehicles (Dawson et al, 2017 ; Scott & Perryman, 1991 ) or portable stereo photogrammetry systems (Howland et al, 2012 ; Macfarlane et al, 2015 ) offers feasible ways of measuring interindividual distances. It is necessary to consider, however, which interindividual distances to measure.…”

Section: Discussionmentioning

confidence: 99%

How to define a dolphin “group”? Need for consistency and justification based on objective criteria

Syme

Kiszka

Parra

2022

Ecology and Evolution

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Group living is a critical component of the ecology of social animals such as delphinids. In many studies on these animals, groups represent sampling units that form the basis of the collection and analysis of data on their abundance, behavior, and social structure. Nevertheless, defining what constitutes a group has proven problematic. There is inconsistency in the terms and criteria used and many definitions lack biological justification. We conducted a literature review and an online expert survey to assess various terms ( group , school , party , and pod ), and their definitions as applied to delphinids to identify issues to ultimately make recommendations. Of 707 studies analyzed, 325 explicitly defined one or more terms, providing 344 definitions. Additionally, 192 definitions were obtained from the survey. Among these definitions, group was the most common term used (review: 286 definitions, 83.1%; survey: 69 definitions, 35.9%) and the most familiar to the survey respondents (73 respondents, 100.0%). In definitions of group , spatial proximity was the most used criterion (review: 200 definitions, 71.2%; survey: 53 definitions, 81.5%) followed by behavior (review: 176 definitions, 62.6%; survey: 38 definitions, 58.5%). The terms and criteria used to define delphinid groups vary considerably. Rather than proposing a single formal definition, we instead recommend that the term group and spatial proximity criteria be used to define sampling units of individuals observed in the field. Furthermore, we propose a process for formulating definitions that involves analyzing interindividual distances to determine naturally occurring patterns that are indicative of group membership. Although this process is based principally on the spatial proximity of individuals, it could also incorporate the behavior of group members by evaluating the influence of behavior on interindividual distances. Such a process produces definitions that are biologically meaningful and compatible across studies and populations, thus increasing our ability to draw strong conclusions about group living in delphinids.

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Section: Discussionmentioning

confidence: 99%

How to define a dolphin “group”? Need for consistency and justification based on objective criteria

Syme

Kiszka

Parra

2022

Ecology and Evolution

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“…For example, static poses and positions of animals can be generated from image and video data, allowing individual tracking and/or pose estimation in a variety of complex and naturalistic environments [29][30][31] . Depth sensing, radio-frequency identification (RFID) tagging, and multiple camera setups have been used in conjunction with standard video data to track animals in social and physical environments in which occlusions regularly occur [32][33][34][35][36] . However, position and pose estimation can only partially describe behaviors that are defined by interactions between animals and their environments, such as construction behaviors.…”

Section: Discussionmentioning

confidence: 99%

Automated measurement of long-term bower behaviors in Lake Malawi cichlids using depth sensing and action recognition

Johnson

Arrojwala

Aljapur

et al. 2020

Sci Rep

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In the wild, behaviors are often expressed over long time periods in complex and dynamic environments, and many behaviors include direct interaction with the environment itself. However, measuring behavior in naturalistic settings is difficult, and this has limited progress in understanding the mechanisms underlying many naturally evolved behaviors that are critical for survival and reproduction. Here we describe an automated system for measuring long-term bower construction behaviors in Lake Malawi cichlid fishes, in which males use their mouths to sculpt sand into large species-specific structures for courtship and mating. We integrate two orthogonal methods, depth sensing and action recognition, to simultaneously track the developing bower structure and the thousands of individual sand manipulation behaviors performed throughout construction. By registering these two data streams, we show that behaviors can be topographically mapped onto a dynamic 3D sand surface through time. The system runs reliably in multiple species, across many aquariums simultaneously, and for up to weeks at a time. Using this system, we show strong differences in construction behavior and bower form that reflect species differences in nature, and we gain new insights into spatial, temporal, social dimensions of bower construction, feeding, and quivering behaviors. Taken together, our work highlights how low-cost tools can automatically quantify behavior in naturalistic and social environments over long timescales in the lab.

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“…Visual observation is a method that is often used for accurate tracking of marine mammals at the surface (e.g. using land-based theodolite tracking [ 23 ], boat-based focal follows [ 43 ], or stereo photogrammetry [ 100 ]), but a quantitative assessment of its accuracy, as presented in this study, is relatively uncommon. The visual accuracy tests with a floating buoy showed that the errors in range generally contributed most to the combined positional error from range and bearing observations, which is consistent with results from more extensive testing during transect line surveys [ 101 ].…”

Section: Discussionmentioning

confidence: 99%

A path reconstruction method integrating dead-reckoning and position fixes applied to humpback whales

2015

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BackgroundDetailed information about animal location and movement is often crucial in studies of natural behaviour and how animals respond to anthropogenic activities. Dead-reckoning can be used to infer such detailed information, but without additional positional data this method results in uncertainty that grows with time. Combining dead-reckoning with new Fastloc-GPS technology should provide good opportunities for reconstructing georeferenced fine-scale tracks, and should be particularly useful for marine animals that spend most of their time under water.We developed a computationally efficient, Bayesian state-space modelling technique to estimate humpback whale locations through time, integrating dead-reckoning using on-animal sensors with measurements of whale locations using on-animal Fastloc-GPS and visual observations. Positional observation models were based upon error measurements made during calibrations.ResultsHigh-resolution 3-dimensional movement tracks were produced for 13 whales using a simple process model in which errors caused by water current movements, non-location sensor errors, and other dead-reckoning errors were accumulated into a combined error term. Positional uncertainty quantified by the track reconstruction model was much greater for tracks with visual positions and few or no GPS positions, indicating a strong benefit to using Fastloc-GPS for track reconstruction. Compared to tracks derived only from position fixes, the inclusion of dead-reckoning data greatly improved the level of detail in the reconstructed tracks of humpback whales. Using cross-validation, a clear improvement in the predictability of out-of-set Fastloc-GPS data was observed compared to more conventional track reconstruction methods. Fastloc-GPS observation errors during calibrations were found to vary by number of GPS satellites received and by orthogonal dimension analysed; visual observation errors varied most by distance to the whale. ConclusionsBy systematically accounting for the observation errors in the position fixes, our model provides a quantitative estimate of location uncertainty that can be appropriately incorporated into analyses of animal movement. This generic method has potential application for a wide range of marine animal species and data recording systems.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-015-0061-6) contains supplementary material, which is available to authorized users.

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A 3D stereo camera system for precisely positioning animals in space and time

Cited by 10 publications

References 36 publications

How to define a dolphin “group”? Need for consistency and justification based on objective criteria

How to define a dolphin “group”? Need for consistency and justification based on objective criteria

Automated measurement of long-term bower behaviors in Lake Malawi cichlids using depth sensing and action recognition

A path reconstruction method integrating dead-reckoning and position fixes applied to humpback whales

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