摘要
标准的环绕声系统需要使用多个扬声器进行声音重放,同时对扬声器的质量也有较好的要求,大多数的普通消费者无法承担高品质扬声器的价格。而虚拟环绕声技术可以很好的解决这一问题,该技术利用头部相关传递函数HRTF(Head-Related Transfer Function)对声音数据进行数字信号处理,通过耳机或者两个扬声器重放放出来,能够让人感觉到环绕声的效果,使听着感觉声音来自某个特定的方向或者被声音环绕。
本论文首先介绍了虚拟环绕声技术的发展以及国内外研究现状,在此基础上分析了虚拟听觉空间相关的理论知识,其中包括影响声源定位的因素与头部相关传递函数。接下来,论文介绍了HRTF数据的获取方法及数据测量概述,并结合多个公开的数据库对HRTF数据进行了特性分析。在第四章中,论文详细阐述了一种基于耳机重放的三维虚拟环绕声系统设计方法,该方法在三维空间中对声音数据进行处理。第五章主要介绍了虚拟环绕声系统在Android手机平台上的实现,其中包括Android系统框架以及音频处理流程的分析,系统实现的软件处理流程与提高实时性处理的措施,并且对系统进行了主观的音频测试,测试结果表明,最终实现的系统具有很好的虚拟环绕声效果。
Standard surround sound system requires multiple speakers for the playback, while the speakers are always of high quality and the majority of ordinary consumers cannot afford the price of the high-quality speakers.But virtual surround sound system can be a good solution to this problem,this technology does some digital signal processing of sound data by using head-related transfer function(HRTF), people can feel the virtual surround sound effect or will locate the sound source from a particular direction when the sound is played with headphones or two speakers.
This paper first introduces the development of virtual surround sound technology, research actuality. Based on that, this paper analyzes the related theoretical knowledge of virtual sound space, including the elements that matters to locate sound source correctly and head-related transfer function. In the next part, this paper focuses on the method of how we can get the HRTF data and the introduction theory of measuring HRTF, and analyzes the characteristics of HRTF data set by using several public HRTF databases.The fourth chapter elaborates the details of the implementation of virtual surround sound system in three-dementional space based on headphone playbacks.This implementation focuses on three-dimentional space to do the sound data processing.The fifth chaper mainly introduces the implementation of virtual surround sound on Android platform, including the analysis of Android frameworks and audio processing flow, the software processing flow and the methods that accelerate the speed of real-time processing. This paper also completes the subjective tests on audio effects of the system. The test result shows that the implemented system can obtain good virtual surround sound effect.
引文
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