The Design Of Underwater Video Compression And Transmission System Based On Sopc

The future is the century of the ocean, the ocean is the important field for human to survival and development. China is a major maritime country, the area of the ocean is more than 3 million square kilometers. Ocean is not only to provide mankind with a wealth of material resources, but also has an important strategic position in modern warfare. Therefore, the research of the recognition of underwater target, has an important value and significance in the national economy and military.For the high-speed processing of underwater video and image signal, underwater video and image compression receives much attention. At the present time, the data transfer rate of commercialized underwater Acoustic Modem is generally a few kb/s, using the limited bandwidth of underwater Acoustic Modem channel, the key technology of real-time transmission of underwater video and image is, firstly, efficient video compression technology, secondly, development of efficient Acoustic Modem. According to the characteristics of underwater video and acoustic channel, we choose efficient video and image compression coding technology, and develop underwater video and image compression and transmission system.The main purpose of this paper is to design an underwater video and image compression and transmission system based on SOPC technology, which can achieve real-time acquisition of underwater video and image, high compression ratio coding, and real-time transmission.According to the characteristics of underwater video and image, for example, poor conditions of underwater light, few species of image colors, low image contrast, the compression algorithms can achieve a compression ratio of 250:1 to 500:1, and it is easy to hardware simulation and realization. Adopting Matlab/Simulink, DSP Builder design flow, the paper has put forward a coding scheme based on hardware implementation.The video main board based on FPGA+DSP, uses six-panel technology, and its size of 178mm*75mm. Video board circuitry includes underwater video and image acquisition module, FPGA core board socket, DSP and its external video processing module, hard disk interface, SD Card interface,232/485 data transfer interface, chip memory module, power module and other control output port. Currently, the main board has been completed. Using FPGAt+DSP design ideas, the project integrates logic devices and digital signal processors with their respective advantages, designs the bus interface logic, achieves the goal of high-speed data transmission and improves the performance of the system. Hardware-based video and image compression coding scheme mainly includes four parts, encoding logical design, address generator design, driver logic design for peripheral devices and NIOS programming design. Encoding logical design is the core work, it includes several encoding operations, for example, lifting wavelet transform, DPCM entropy coding, scan coding based on Wavelet Tree, block matching operation and so on. The project constructs Simulink models and takes simulation for these coding algorithms respectively, and converts into Quartus projects for timing simulation. Finally, the paper has summarized the work, and predicted the next step in future.