Design And Implementation Of UAV Ultra-clear Real-time Image Transmission System Based On 5G Network

Image transmission system is one of the important components of UAV.With the expansion of UAV application field,people have higher and higher requirements for image transmission system.The traditional UAV image transmission system has some shortcomings in real-time,clarity,transmission distance and so on.In view of the above problems,this thesis designs a UAV ultra clear real-time image transmission system based on 5G network.The system can be conveniently deployed on various UAVs,so that UAVs can obtain the ability of ultra clear real-time image transmission,and can be widely used in UAV application fields such as digital imaging,rescue and disaster relief,power patrol inspection,etc.The system has high practical application value.The image transmission system designed in this thesis is mainly composed of three parts:the video sender,server end and client end.The video sender is deployed on the UAV,and based on Hisilicon professional video processing chip hi3519av100,the video is processed,encoded,packaged into RTMP format,and streamed to the cloud SRS streaming media server.The video sender of the UAV communicates with the streaming media server through 5G network,and the client pulls streams from the streaming media server in real time.The main contents of this thesis are as follows:（1）Based on Hisilicon HI3519AV100 embedded platform,the video collected by the camera is processed and encoded.The built-in digital image signal processing algorithm in the ISP unit is used for image optimization.The digital anti shake function is realized through the DIS module to solve the problems of poor image quality and serious video jelly effect from the source.Video coding is carried out through the built-in h265 hardware encoder on the chip,which greatly improves the coding efficiency.For the 4K image transmission application scenario of UAV with large video scene changes and low delay requirements,Dual intelligent coding mode and AVBR rate control strategy are selected to save video rate and reduce coding delay.（2）Based on ZTE ZM9000 module,5G wireless communication function is realized.The part about flv packaging in ffmpeg and SRS open source framework is modified to solve the problem that the official RTMP protocol does not support h265 format.Ffmpeg is simply transplanted to HI3519AV100 embedded platform to realize video packaging and streaming.（3）Based on the ffmpeg and QT open source framework,a customized image transmission system client is designed.By manually setting the stream information,the problem of long detection time of the first frame video format is solved.Through the optimization and acceleration of the CPU special instruction set by libyuv,the problem of low efficiency of the ffmpeg video format conversion function is solved.GPU hardware decoding is adopted to solve the problem of low software decoding efficiency,and an optimization scheme is proposed to solve the problems of inaccurate jump and asynchronous audio and video when playing local video.This thesis designs and implements an ultra clear real-time image transmission system for UAV,and comprehensively tests the image transmission system.Through the test,the reliability and stability of the system are verified.The average image transmission delay of the system is about 500 ms,and the peak signal-to-noise ratio of the video encoded image in the dynamic environment is higher than 33 d B,which can meet the technical requirements of ultra clear video image transmission for UAV.