Iterative 3-D Pose Correction and Content-Based Image Retrieval for Dorsal Fin Recognition

Stewman, John; Debure, Kelly R.; Hale, Scott A.; Russell, Adam

doi:10.1007/11867586_60

Cited by 10 publications

(6 citation statements)

References 8 publications

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“…The relative accuracy, which was shown by Gamble et al (2008) to be constant with increasing catalogue size, was measured as the proportion of true matches that are ranked within the first 10% of the catalogue. Our program's relative accuracy was 77.5%, which is within the 50%-80% range achieved by other matching programs (Stewman et al, 2006;Finerty et al, 2007).…”

Section: Discussionsupporting

confidence: 72%

Computer-Assisted Photo-Identification of Narwhals

Auger‐Méthé¹,

Marcoux²,

Whitehead³

2011

ARCTIC

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ABSTRACT. Although the narwhal (Monodon monoceros) is economically and culturally important to northern residents, sound management of this species is impaired by large gaps in knowledge. Research on this species has been limited partly by the cost of the methods used, and partly because some of these methods are invasive and therefore condemned by Inuit communities. Photo-identification, a non-invasive, inexpensive, and easy-to-use method recently developed for narwhals, uses photographs of natural marks to identify individuals. Its main drawback is the extended time required to process photographs. We developed a computer program to accelerate the identification process and thus mitigate the main drawback of photoidentification. This program uses the locations of notches on the dorsal ridge to compare a new image to each individual in a catalogue and lists those individuals in decreasing order of similarity. We tested consistency in user assignment of dorsal ridge features and the accuracy of the program by comparing sets of known individuals. While assignment errors were common, the program ranked the true match within the first 10% of the catalogue 78% of the time. The program accelerates the matching process by 1.2 to 4.1 times for catalogues ranging in size from 40 to 500 individuals, and the degree of acceleration increases with the size of the catalogue. This program could also be applied to the beluga whale (Delphinapterus leucas), another important northern species.Key words: Arctic, individual identification, Monodon monoceros, narwhal, non-invasive methods, photo-identification, software RÉSUMÉ. Bien que le narval (Monodon monoceros) soit une espèce exploitée d'importance économique et culturelle pour les résidents du Nord, la gestion efficace de cette espèce est affaiblie par des lacunes importantes en matière de connaissance de l'espèce. La quantité de recherche sur le narval est limitée par le coût des méthodes utilisées et par le fait que certaines de ces méthodes sont invasives, ce qui est désapprouvé par les communautés inuites. La photo-identification, soit une méthode non-invasive, peu coûteuse et facile d'utilisation, a été récemment mise au point pour le narval. Cette méthode utilise des photographies de marques naturelles pour identifier les individus. Toutefois, le plus grand défaut de cette méthode est qu'elle requiert beaucoup de temps pour comparer les photographies. Nous avons mis au point un programme informatique dans le but d'accélérer le processus d'identification et donc remédier au principal inconvénient de la photo-identification. Ce programme utilise l'emplacement des entailles dans la crête dorsale des narvals pour comparer une nouvelle image à celles d'un catalogue et les ordonne en ordre décroissant selon leur similarité. Nous avons testé la constance de l'utilisateur lorsqu'il attribue les caractéristiques de la crête dorsale et l'exactitude du programme en comparant des photographies d'individus précédemment identifiés. Bien que les erreurs de l'utilisateur soient fréquen...

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Section: Discussionsupporting

confidence: 72%

Computer-Assisted Photo-Identification of Narwhals

Auger‐Méthé¹,

Marcoux²,

Whitehead³

2011

ARCTIC

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“…Würsig & Jefferson (1990). Photographs were analyzed and compared by at least two investigators using the Nikon View software and, more recently, Darwin (Stewman et al 2006). Catalogs were compared among areas to find matches of identified individuals, the main evidence of movement between two different locations.…”

Section: Methodsmentioning

confidence: 99%

Cetacean movements in coastal waters of the southwestern Atlantic ocean

Santos

Lailson‐Brito

Flach³

et al. 2019

Biota Neotrop.

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Cetaceans were monitored along ca. 700 km of the southeast coast of Brazil (22°S to 25°S) from 1995 to 2014 using photo-identification. The objective of this study was to identify any presence of long-distance movements for monitored cetacean species and discuss implications. Data on long-range movements of four of the monitored species are presented after the analysis of 321,765 photographs taken for individual identification. Seven individuals from four populations of Guiana dolphins (Sotalia guianensis) considered resident to particular estuaries or bays were reported in dispersal involving movement between pairs of protected areas over long-range distances varying between 86 and 135 km. Three cataloged rough-toothed dolphins (Steno bredanensis), first seen in Guanabara Bay, Rio de Janeiro state (22°46'S) in November 2011, were sighted 240 km southwards as members of the same group in coastal waters of São Paulo state (23°46'S) in July 2014. Water depth for those sightings ranged from 16 to 52.7 m; local sightings of rough-toothed dolphins in Brazil have frequently been in shallow waters, but the species global distribution is usually associated with deeper waters. In a 27-day interval in the spring of 2012, a group of 16 orcas (Orcinus orca) travelled ca. 277 km in shallow coastal waters ranging from 20 to 30 m deep. Orcas are commonly observed between November and February in southeast Brazil, probably in search for prey. In summer months between 2012 and 2014, three Bryde's whales (Balaenoptera edeni) sighted in waters ranging from 14 to 49 m deep, moved between 218 and 327 km. Bryde's whales are usually found in local coastal waters where they spend summer months feeding on sardines. To date, these are the longest estimated movements reported to S. guianensis, S. bredanensis, O. orca and B. edeni in the Southwestern Atlantic Ocean.

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“…Additionally, the proportion of the dorsal fin out of the water and the amount of water splash were also considered in the appropriate choice of photos (for more details, see Santos & 652 Victor Uber Paschoalini and Marcos César de Oliveira Santos Rosso, 2008). Darwin software was used to model photographs (see Stewman et al, 2006), and all matches were manually checked. Individual movements were analysed using estimated Euclidean distances within ArcGIS (ESRI, USA), following the shoreline whenever physical barriers such as islands were found in the middle of the path.…”

Section: Photo-identification Analysesmentioning

confidence: 99%

Movements and habitat use of bottlenose dolphins,Tursiops truncatus, in south-eastern Brazil

Paschoalini

Santos

2020

J. Mar. Biol. Ass.

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Bottlenose dolphins (Tursiops truncatus) have been surveyed for at least two decades on the southern Brazilian coast. However, little is known about their distribution and habitat use in lower latitudes of the South-western Atlantic Ocean. Aiming to study the movements and distribution of the species along the south-eastern Brazilian coast, we made a comparison of photo-identified individuals of the species catalogued in 21 cruises conducted between 2012 and 2015. Additionally, we performed stable isotope analyses of carbon and nitrogen in skin samples (N = 35) to provide some insights of dolphin habitat use and trophic ecology through comparisons among individuals of distinct surveyed sectors (northern and southern) and sex. A total of 177 individuals were identified. Re-sightings (N = 24) occurred at intervals from 82 to 979 days at distances from 7 to 179 km. No individual was sighted in both sectors, suggesting spatial segregation. Isotopic comparisons showed no significant differences in carbon and nitrogen signatures between distinct sectors. However, ecological divergences were found when we divided the samples by gender. Wider isotopic niches were found for the northern bottlenose dolphins vs the southern ones, which could be related to temporal and spatial variation in the availability of resources, as well as possible differences in the home ranges of males and females in each region. This study represents a preliminary evaluation of ecological aspects of bottlenose dolphins along the Brazilian south-eastern coast, however, long-term studies on the feeding ecology and habitat use of this species are important to further improve our knowledge.

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Iterative 3-D Pose Correction and Content-Based Image Retrieval for Dorsal Fin Recognition

Cited by 10 publications

References 8 publications

Computer-Assisted Photo-Identification of Narwhals

Computer-Assisted Photo-Identification of Narwhals

Cetacean movements in coastal waters of the southwestern Atlantic ocean

Movements and habitat use of bottlenose dolphins,Tursiops truncatus, in south-eastern Brazil

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