基于WebRTC的可视对讲系统的研究与实现

发布时间：2018-01-12 17:19

本文关键词：基于WebRTC的可视对讲系统的研究与实现　出处：《安徽工程大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着生活水平的不断提高,人们对生活和居住的要求也逐渐提高,人们对社区的安全性和便捷性越来越重视,可视对讲系统逐渐要求成为智能化的设备终端,以满足人们对智慧生活的需要。传统的可视对讲系统中功能单一,多媒体性能差,尤其是语音通话质量不高,存在着回声、失真等情况。本文将网页实时通信(Web Real-Time Communication,简写WebRTC)技术应用到可视对讲中,设计了基于WebRTC的可视对讲系统。其中主要工作包括：分析WebRTC技术构架,研究其音频引擎、视频引擎和网络传输的工作原理,研究整个软件系统的处理流程、编程接口、数据通道等。针对可视对讲中存在回声的难题,对消回声算法LMS、NLMS、 RLS、PNLMS进行研究分析比较和仿真。在原有算法基础上提出采用一种改进算法,并进行仿真分析,最后再将改进算法移植到WebRTC中。完成可视对讲系统的嵌入式硬件平台的搭建,主要包括对门口机和智能底座的硬件电路设计和PCB设计。门口机以高集成度A20处理器为核心,搭载Android操作系统。该处理器基于双核ARM Cortex-A7 CPU架构,可以很好的支持Android4.2系统,其中它的语音视频处理能力尤其突出。智能底座采用TI的CC2530为处理器,这是基于ZigBee无线解决方案的芯片,这也为我们后期智能家居开发扩展提供了良好的空间。参与完成门口机客户端软件设计,包括音频模块软件、视频模块软件和控制软件,并对消回音算法进行软件实现。最后对整个可视对讲系统进行功能和性能测试,其中重点对门口机语音方面性能进行测试。测试结果表明,系统图像显示、语音质量已经达到原先设计要求。该可视对讲系统性能优异,语音和视频处理能力强,实际应用效果较好,具有良好的工程应用价值。
[Abstract]:With the continuous improvement of living standards, people's living and living requirements are also gradually improved, people pay more and more attention to the security and convenience of the community, visual intercom system is gradually required to become an intelligent device terminal. In order to meet the needs of intelligent life, the traditional visual intercom system has a single function, poor multimedia performance, especially the voice call quality is not high, there is an echo. In this paper, the technology of web Real-Time communication is applied to visual intercom. A visual intercom system based on WebRTC is designed. The main work includes: analyzing the technical framework of WebRTC, studying the working principle of audio engine, video engine and network transmission. The processing flow, programming interface, data channel and so on of the whole software system are studied. Aiming at the difficult problem of echo in visual intercom, the echo cancellation algorithm LMS / NLMS, RLS is proposed. PNLMS carries on the research analysis and the simulation. On the basis of the original algorithm, an improved algorithm is proposed, and the simulation analysis is carried out. Finally, the improved algorithm is transplanted into WebRTC to build the embedded hardware platform of visual intercom system. It mainly includes the hardware circuit design and PCB design of the door machine and the intelligent base. The door machine takes the high integration A20 processor as the core. Run on Android operating system. This processor is based on dual-core ARM Cortex-A7 CPU architecture, which can support Android4.2 system very well. The intelligent base uses TI's CC2530 as the processor, which is a chip based on ZigBee wireless solution. This also provides a good space for our later smart home development extension. Participate in the door machine client software design, including audio module software, video module software and control software. Finally, the function and performance of the whole visual intercom system are tested, among which the speech performance of the door machine is tested. The test results show that the system image is displayed. The quality of speech has reached the original design requirements. The system has excellent performance, strong speech and video processing ability, good practical application effect, and has good engineering application value.
【学位授予单位】：安徽工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.54

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