Please use this identifier to cite or link to this item:
logo share SHARE logo core CORE BASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE

A New Colorimetrically-Calibrated Automated Video-Imaging Protocol for Day-Night Fish Counting at the OBSEA Coastal Cabled Observatory

AuthorsRío, Joaquín del; Aguzzi, Jacopo CSIC ORCID ; Costa, Corrado; Menesatti, Paolo; Sbragaglia, Valerio CSIC ORCID ; Nogueras, Marc; Sardà, Francisco CSIC ORCID; Mànuel, Antoni
Keywords3D Thin-Plate Spline warping
Swimming rhythms
Colorimetric calibration
Automated video-imaging
Cabled observatories
Coastal fishes
Issue DateOct-2013
PublisherMultidisciplinary Digital Publishing Institute
CitationSensors 13(11): 14740-14753 (2013)
AbstractField measurements of the swimming activity rhythms of fishes are scant due to the difficulty of counting individuals at a high frequency over a long period of time. Cabled observatory video monitoring allows such a sampling at a high frequency over unlimited periods of time. Unfortunately, automation for the extraction of biological information (i.e., animals' visual counts per unit of time) is still a major bottleneck. In this study, we describe a new automated video-imaging protocol for the 24-h continuous counting of fishes in colorimetrically calibrated time-lapse photographic outputs, taken by a shallow water (20 m depth) cabled video-platform, the OBSEA. The spectral reflectance value for each patch was measured between 400 to 700 nm and then converted into standard RGB, used as a reference for all subsequent calibrations. All the images were acquired within a standardized Region Of Interest (ROI), represented by a 2 × 2 m methacrylate panel, endowed with a 9-colour calibration chart, and calibrated using the recently implemented >3D Thin-Plate Spline> warping approach in order to numerically define color by its coordinates in n-dimensional space. That operation was repeated on a subset of images, 500 images as a training set, manually selected since acquired under optimum visibility conditions. All images plus those for the training set were ordered together through Principal Component Analysis allowing the selection of 614 images (67.6%) out of 908 as a total corresponding to 18 days (at 30 min frequency). The Roberts operator (used in image processing and computer vision for edge detection) was used to highlights regions of high spatial colour gradient corresponding to fishes' bodies. Time series in manual and visual counts were compared together for efficiency evaluation. Periodogram and waveform analysis outputs provided very similar results, although quantified parameters in relation to the strength of respective rhythms were different. Results indicate that automation efficiency is limited by optimum visibility conditions. Data sets from manual counting present the larger day-night fluctuations in comparison to those derived from automation. This comparison indicates that the automation protocol subestimate fish numbers but it is anyway suitable for the study of community activity rhythms. © 2013 by the authors; licensee MDPI, Basel, Switzerland
Description14 pages, 8 figures
Publisher version (URL)
Identifiersdoi: 10.3390/s131114740
issn: 1424-8220
Appears in Collections:(ICM) Artículos

Files in This Item:
File Description SizeFormat
Del_Rio_et_al_2013.pdf748,21 kBAdobe PDFThumbnail
Show full item record
Review this work

PubMed Central

checked on Jan 14, 2022


checked on Jan 12, 2022


checked on Jan 18, 2022

Page view(s)

checked on Jan 20, 2022


checked on Jan 20, 2022

Google ScholarTM




Related articles:

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.