FIN-PRINT a fully-automated multi-stage deep-learning-based framework for the individual recognition of killer whales

• Published in: Scientific Reports
• Main Authors: Bergler, Christian, Gebhard, Alexander, Towers, Jared R., Butyrev, Leonid, Sutton, Gary J., Shaw, Tasli J. H., Maier, Andreas, Nöth, Elmar
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: ddc:000; Killer Whale; Killer whale
• Online Access: https://opus4.kobv.de/opus4-fau/frontdoor/index/index/docId/19533; https://nbn-resolving.org/urn:nbn:de:bvb:29-opus4-195333; https://doi.org/10.1038/s41598-021-02506-6; https://opus4.kobv.de/opus4-fau/files/19533/s41598-021-02506-6.pdf

Biometric identification techniques such as photo-identification require an array of unique natural markings to identify individuals. From 1975 to present, Bigg’s killer whales have been photo-identified along the west coast of North America, resulting in one of the largest and longest-running cetacean photo-identification datasets. However, data maintenance and analysis are extremely time and resource consuming. This study transfers the procedure of killer whale image identification into a fully automated, multi-stage, deep learning framework, entitled FIN-PRINT. It is composed of multiple sequentially ordered sub-components. FIN-PRINT is trained and evaluated on a dataset collected over an 8-year period (2011–2018) in the coastal waters off western North America, including 121,000 human-annotated identification images of Bigg’s killer whales. At first, object detection is performed to identify unique killer whale markings, resulting in 94.4% recall, 94.1% precision, and 93.4% mean-average-precision (mAP). Second, all previously identified natural killer whale markings are extracted. The third step introduces a data enhancement mechanism by filtering between valid and invalid markings from previous processing levels, achieving 92.8% recall, 97.5%, precision, and 95.2% accuracy. The fourth and final step involves multi-class individual recognition. When evaluated on the network test set, it achieved an accuracy of 92.5% with 97.2% top-3 unweighted accuracy (TUA) for the 100 most commonly photo-identified killer whales. Additionally, the method achieved an accuracy of 84.5% and a TUA of 92.9% when applied to the entire 2018 image collection of the 100 most common killer whales. The source code of FIN-PRINT can be adapted to other species and will be publicly available.