Abstract
Particle size estimation is key to understanding carbon fluxes and storage in the marine ecosystem. Images of particles provide much information about their size. A subsea digital holographic camera was used to image particles in vertical trajectory in South Georgia. The holograms were processed using a rapid hologram processing suite that extracted focused particle vignettes from these raw holograms. A machine-learning-based method has been developed to analyse the particle size information from these vignettes. To be specific, a structured-forest-based model trained on a group of synthetic holographic particle images is used to detect the particle edges in these vignettes. Following that, a set of pixel-wise morphology operators are used to extract particle regions (masks) from their edge images. Lastly, the size information of the recorded particles can be calculated based on these mask images. The proposed method has been evaluated on a group of synthetic holograms and real holograms, compared with the other ten methods, including four edge-based methods, four region-based methods, a thresholding-based method, and a Kmeans-based method. The results show that our method has the best performance regarding accuracy and processing time. It reaches ∼0.7 of mean IoU and ∼25 s of running time on the 1,000 test vignettes. In terms of qualitative analysis, the regions of the given examples extracted by the proposed method closely match the real particle regions. We also use this method to analyse the size distributions of two profiles, and some generic results are given in this paper.
Original language | English |
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Title of host publication | OCEANS 2023 - Limerick |
Publisher | IEEE Explore |
Pages | 1-8 |
Number of pages | 8 |
ISBN (Electronic) | 979-8-3503-3226-1 |
ISBN (Print) | 979-8-3503-3227-8 |
DOIs | |
Publication status | Published - 12 Sept 2023 |
Event | OCEANS 2023 Limerick : Blue Ocean Planet Earth - Limerick, Ireland Duration: 5 Jun 2023 → 8 Jun 2023 https://limerick23.oceansconference.org/ |
Conference
Conference | OCEANS 2023 Limerick |
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Country/Territory | Ireland |
City | Limerick |
Period | 5/06/23 → 8/06/23 |
Internet address |
Bibliographical note
ACKNOWLEDGMENT:We thank Richard Lampitt, Morten Iversen and Kevin Saw for the deployment of the Red Camera Frame. Our thanks extend to the captain, crew and scientists of the research cruise DY086. This work was supported through the ANTICS project, receiving funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No 950212). Data were collected as part of the COMICS project (Controls over Ocean Mesopelagic Interior Carbon Storage; NE/M020835/1) funded by the Natural Environment Research Council.
Keywords
- subsea digital holography
- size estimation
- Particle size distribution
- hologram processing
- Machine Learning