针对火灾现场无线信道环境恶劣、误码率较高等问题,提出了一种基于多硬件编码器协同的信源信道联合编码方案。采用复合控制方法,闭环控制方面,接收端将视频质量评估结果实时反馈给发送端进行发送质量调整;开环控制方面,针对反馈信道可能失败的问题,采用3个编码器对来自同一热像仪的视频进行不同压缩比的H.264编码,根据陀螺仪提供的热像仪姿态参数,选择其中最适合的一个码流送入数传电台。试验结果表明,该系统在保证带宽要求的基础上,提高了PSNR(peak signal to noise ratio)值,并提高了系统的实时性与可靠性。
Aiming at the poor wireless channel ang high error rate at the scene of fire, a joint source channel coding based on the multi-hardware encoder was proposed. With the compound control method, the receiving end would send the video quality evaluation result to the sending end in real time from the closed-loop control. Aiming at the possible failure of feedback channel, 3 encodes were employed for the H. 264 encoding of different compression ratio for the same thermal imager from the open-loop control. Meanwhile, the most appropriate code stream was selected to be loaded into the data transfer ratio according to the attitude parameters of thermal imager provided by the gyroscope. Experimental results showed that the PSNR (peak signal to noise ratio), real-time capabilitiness, and reliabilitiness were im- proved on the basis of the guarantee of certain bandwidth.