Research On Underwater Video Transmission System Based On Optical Fiber Communication And Video Image Processing Technology

In the process of underwater information collection,processing and transmission,real-time monitoring of the underwater environment and resource exploration require the use of camera systems and various sensors,which can accurately and quickly complete tasks such as underwater information collection and resource development.In response to the needs of underwater information transmission,this paper designs and implements an underwater video transmission system based on optical fiber communication,completes the uncompressed,digitized,real-time and long-distance transmission of video signals,meanwhile analyzed and processed the captured fish video information.The system is mainly composed of five parts,including video source acquisition part,data processing part,optical fiber data transmission part,system control part and video acquisition storage part.The video source is collected through the 3G-SDI camera,and a blue light source is added for underwater detection and illumination.The data processing part is the core of the transmission system,mainly responsible for the processing of video data and high-definition lossless transmission.The optical fiber data transmission part is mainly composed of light emitting end and light receiving end,and performs optical-electro/electro-optical conversion.The optical fiber is a communication channel in which high-speed transmission is performed.The system control part completes the control of the switch of the SDI camera,the rotation of the motor,the switching of the light source,and the power supply of the entire system.The last part is the video acquisition and storage part,which collects and stores the video signal at the optical receiving end.In terms of hardware design,FPGA/CPLD is used as the core processing board,which mainly completes the analog-to-digital and digital-to-analog conversion of video data,as well as the analysis of combinational logic and sequential logic.The low-power single-chip microcomputer is used to complete the system control.In optical fiber data transmission,an optical transmitting module and an optical receiving module are used.The emitting end converts electrical signals into optical signals to complete the transmission of signals in the optical fiber,and the receiving end converts the optical signals into electrical signals in order to restore video data.To transmit data in optical fiber,the signal must be encoded and decoded.It is mainly using 8B/10 B encoding and decoding method.In software design,the monitoring interface is mainly designed using pycharm development tools and python language,which more intuitively displays video data.At the same time,using Visual Studio2017 development tools and OpenCV for underwater video image processing,using the inter-frame difference method and the background separation method based on the mixed Gaussian model to detect fish.People can determine the trajectory and number of fish.