The Design And Research Of Sampling System Of Underwater Compressed Imaging Technology

Now the understanding and development of marine have become the consensusall over the world，where underwater optical imaging is the important technologyfor marine scientific research. Because the absorption and scattering of water andparticles to light energy， the sampling signal is difficult to satisfy the Nyquistsampling frequency and become a big bottleneck of underwater optical imaging. Inrecent years the emergence of compressed sensing（CS）theory provides a brand newidea to solve this problem， this thesis is devoted to test underwater compressedimaging (UCI) technology, which integrates the CS theory.Firstly, this paper studied optical properties of seawater，technical ideas ofunderwater laser range-gated imaging system and working mechanism of single pixelcamera，which laying a theoretical foundation for the research of UCI technology andits sampling system.Secondly, after researching various kinds of photo detector we selected thephotomultiplier (PMT) as the detector. In light of the thorough research onsingle pixel sampling system, it has been found that this system always needsbeforehand measurements and compensated operations, leading to complexcalculation and larger system error. To resolve the above problems and improve theperformance of the single pixel sampling system, double PMT structure has beendesigned.Thirdly, the optical, mechanical and electronic design scheme ofunderwater compressed sampling system was proposed on the basis of double PMTstructure. Then the sampling system has been designed through two aspects which arelight transmission system and compressed sensing system. After verified bysimulation, prototype for UCI technology has been processed. The result obtainedfrom stable light source and non-stable light source illumination experiments hasshown that compressed imaging has good robust, gradualness and scalability. In themeantime, we succeeded in matching the laser and compressed sampling system, andfinding the main error sources from the laser illumination experiment.Finally, in order to overcome these disadvantages of prototype such as long timeand large data for sampling, the upgrading scheme for DMD on the basis of FPGA has been presented in this paper, which is able to enhance the performance of UCItechnology.