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Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis

Action sport cameras (ASC) are currently adopted mainly for entertainment purposes but their uninterrupted technical improvements, in correspondence of cost decreases, are going to disclose them for three-dimensional (3D) motion analysis in sport gesture study and athletic performance evaluation qua...

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Autores principales: Bernardina, Gustavo R. D., Cerveri, Pietro, Barros, Ricardo M. L., Marins, João C. B., Silvatti, Amanda P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4981397/
https://www.ncbi.nlm.nih.gov/pubmed/27513846
http://dx.doi.org/10.1371/journal.pone.0160490
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author Bernardina, Gustavo R. D.
Cerveri, Pietro
Barros, Ricardo M. L.
Marins, João C. B.
Silvatti, Amanda P.
author_facet Bernardina, Gustavo R. D.
Cerveri, Pietro
Barros, Ricardo M. L.
Marins, João C. B.
Silvatti, Amanda P.
author_sort Bernardina, Gustavo R. D.
collection PubMed
description Action sport cameras (ASC) are currently adopted mainly for entertainment purposes but their uninterrupted technical improvements, in correspondence of cost decreases, are going to disclose them for three-dimensional (3D) motion analysis in sport gesture study and athletic performance evaluation quantitatively. Extending this technology to sport analysis however still requires a methodologic step-forward to making ASC a metric system, encompassing ad-hoc camera setup, image processing, feature tracking, calibration and 3D reconstruction. Despite traditional laboratory analysis, such requirements become an issue when coping with both indoor and outdoor motion acquisitions of athletes. In swimming analysis for example, the camera setup and the calibration protocol are particularly demanding since land and underwater cameras are mandatory. In particular, the underwater camera calibration can be an issue affecting the reconstruction accuracy. In this paper, the aim is to evaluate the feasibility of ASC for 3D underwater analysis by focusing on camera setup and data acquisition protocols. Two GoPro Hero3+ Black (frequency: 60Hz; image resolutions: 1280×720/1920×1080 pixels) were located underwater into a swimming pool, surveying a working volume of about 6m(3). A two-step custom calibration procedure, consisting in the acquisition of one static triad and one moving wand, carrying nine and one spherical passive markers, respectively, was implemented. After assessing camera parameters, a rigid bar, carrying two markers at known distance, was acquired in several positions within the working volume. The average error upon the reconstructed inter-marker distances was less than 2.5mm (1280×720) and 1.5mm (1920×1080). The results of this study demonstrate that the calibration of underwater ASC is feasible enabling quantitative kinematic measurements with accuracy comparable to traditional motion capture systems.
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spelling pubmed-49813972016-08-29 Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis Bernardina, Gustavo R. D. Cerveri, Pietro Barros, Ricardo M. L. Marins, João C. B. Silvatti, Amanda P. PLoS One Research Article Action sport cameras (ASC) are currently adopted mainly for entertainment purposes but their uninterrupted technical improvements, in correspondence of cost decreases, are going to disclose them for three-dimensional (3D) motion analysis in sport gesture study and athletic performance evaluation quantitatively. Extending this technology to sport analysis however still requires a methodologic step-forward to making ASC a metric system, encompassing ad-hoc camera setup, image processing, feature tracking, calibration and 3D reconstruction. Despite traditional laboratory analysis, such requirements become an issue when coping with both indoor and outdoor motion acquisitions of athletes. In swimming analysis for example, the camera setup and the calibration protocol are particularly demanding since land and underwater cameras are mandatory. In particular, the underwater camera calibration can be an issue affecting the reconstruction accuracy. In this paper, the aim is to evaluate the feasibility of ASC for 3D underwater analysis by focusing on camera setup and data acquisition protocols. Two GoPro Hero3+ Black (frequency: 60Hz; image resolutions: 1280×720/1920×1080 pixels) were located underwater into a swimming pool, surveying a working volume of about 6m(3). A two-step custom calibration procedure, consisting in the acquisition of one static triad and one moving wand, carrying nine and one spherical passive markers, respectively, was implemented. After assessing camera parameters, a rigid bar, carrying two markers at known distance, was acquired in several positions within the working volume. The average error upon the reconstructed inter-marker distances was less than 2.5mm (1280×720) and 1.5mm (1920×1080). The results of this study demonstrate that the calibration of underwater ASC is feasible enabling quantitative kinematic measurements with accuracy comparable to traditional motion capture systems. Public Library of Science 2016-08-11 /pmc/articles/PMC4981397/ /pubmed/27513846 http://dx.doi.org/10.1371/journal.pone.0160490 Text en © 2016 Bernardina et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Bernardina, Gustavo R. D.
Cerveri, Pietro
Barros, Ricardo M. L.
Marins, João C. B.
Silvatti, Amanda P.
Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis
title Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis
title_full Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis
title_fullStr Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis
title_full_unstemmed Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis
title_short Action Sport Cameras as an Instrument to Perform a 3D Underwater Motion Analysis
title_sort action sport cameras as an instrument to perform a 3d underwater motion analysis
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4981397/
https://www.ncbi.nlm.nih.gov/pubmed/27513846
http://dx.doi.org/10.1371/journal.pone.0160490
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