Underwater Imaging Technology Research Based On Adaptive Optics

The widely use of range-gated imaging technology and synchronous scanningimaging technology makes the importance of underwater imaging distance gettingbigger and bigger. According to the results of the research for atmosphericturbulence, underwater-turbulence will be an important potential factor for theperformance of underwater imaging system. However, there is almost nobody hasmade a further research in this field at present, which still remained theunderwater-turbulence problem as an unknown factor in the study of under-waterlaser imaging system and laser communication system. In this paper, we havemade a study of the underwater-turbulence, further more, we also finished sameresearch of the application of adaptive optics in under-water imaging system. Themain content of this paper include:(1).The study of the main factors (interface of water-glass-air, absorption,scattering, Underwater-turbulence) which have effect on the quality of under-waterimages has been investigated, and common ways to improve the quality ofunder-water images have been found. By analyzing of shortage of presentunder-water imaging technology, we want to overcome the problem owing to theunderwater-turbulence by adaptive optical technology.(2).The principle of adaptive optics has been expatiated. The ways of thewave-front process and the principles of the Shack-Hartmann sensor and deformablemirror have also been studied as the key technology and apparatus of adaptive optics.Furthermore, KeckⅡ telescope has been introduced to show the components andapplication of adaptive optics.(3).The applicability and constraints of the application of adaptive optics hasbeen expatiated. Then, the impact of underwater-turbulence on laser beampropagation is studied based on wave-front test. The value of the distortionintroduced by underwater-turbulence is measured and analyzed by using the Zernikepolynomial. The adaptive optical system based on wave-front compensation appliedin underwater imaging system is studied. Finally, calibration experiment is carried out to show that adaptive optical system can improve the quality of underwaterimaging images effectively.