Study Of Marine Plankton Image Capture System In Real Time

Marine plankton plays an important role in the whole marine ecosystem. The biological diversity and biomass of plankton have a significant impact on the entire marine ecosystem structure and function. The structural changes in plankton populations play a significant role in the entire marine food chain of the ecological structure and the flux of organic matter delivered to the deep-sea. The degradation of temporal and spatial distribution of plankton is a main factor to the decline of other marine life. So the changes of plankton biomass, population structure, community diversity, geographic distribution and physiology have vital influence on ecological and environmental protection and the continuable development of marine economics.Underwater monitoring techniques with high spatial resolution and time scale are needed to observe the changes in the process of plankton reproduction, growth and demise cycle. Traditional methods for plankton biomass survey are using the bio-trawl with manual analysis, statistics in labs which costs a lot of time. The spatial resolution of a few meters or tens of meters of the traditional methods can't meet the requirements of today's plankton research. Underwater optical imaging technology can provide the information within the scope of horizontal and vertical distribution and abundance of plankton with high-resolution, which undoubtedly improves the efficiency and accuracy of underwater observation.As there's a wide gap with developed country on the monitoring plankton in situ and real-time, a prototype of plankton image capture system has been designed. An combination of extender and extension tube has been made to form an image system with magnification of 0.759, object distance of 502mm, field of view of 12.5mm×9.5mm, depth of field of 5.7cm, the size of plankton that can be monitored between 303μm and 15.49mm.In order to meet the requirements of small size, low power consumption, high resolution for plankton monitoring in situ and real time, an embedded image capture system based on PC/104-Plus has been designed. Hardware and software for the system have been chosen and integrated. The image resolution captured is 1390pixel×1037pixel.The capture speed is 15 frames per second and the maximal power consumption is 24.96 watt.Light illumination of different angles has been experimented in order to reduce the influence caused by the optic characters of the sea water. The results have provided a basis on obtaining high-contrast images of plankton.Simulation experiments of plankton image capture in a water vessel in labs have been done to test the system designed. The experiment results show that the system designed is capable to get clear images of plankton.The prototype of marine plankton image capture system designed in the thesis makes theoretic and practical foundation for research on plankton quantity, distribution and identification.