Computer vision and deep learning meet plankton: Milestones and future directions

Planktonic organisms play a pivotal role within aquatic ecosystems, serving as the foundation of the aquatic food chain while also playing a critical role in climate regulation and the production of oxygen. In recent years, the advent of automated systems for capturing in-situ images has led to a huge influx of plankton images, making manual classification impractical. This, at the same time, has opened up opportunities for the application of machine learning and deep learning solutions. This paper undertakes an extensive analysis of the broad range of computer vision techniques and methodologies that have emerged to facilitate the automatic analysis of small- to large-scale datasets containing plankton images. By focusing on different computer vision tasks, we present findings and limitations in order to offer a comprehensive overview of the current state-of-the-art, while also pinpointing the open challenges that demand further research and attention.