Research on detecting plankton based on darkfield microscopy

Plankton is an important part of the marine life, which plays a significant role in studying the change of global climate and the marine ecological environment. In order to detect plankton accurately and effectively, we design the Underwater In-situ Dark-field Microscopy Detection System based on the principle of dark-field microscopy. The experiment results show that while the 2× microscope objective is used, the resolution is 90.5lp/mm and the horizontal field of view is 2.6×2.6mm and while the 10× microscope objective is used, the resolution is 181lp/mm and the horizontal field of view is 2.2×2.2mm, when the microscope objective is replaced by 0.9× large format telecentric lens, the detection area will be 11mm with the resolution of 32lp/mm. Double compartment structure is designed, such that the system can work underwater.