浅析语音编码的三个发展方向

简要分析了当前语音编码总体上三个大的发展方向：极低速率语音编码、变速率语音编码和不压缩语音编码,并说明了它们的应用领域。只有把握了语音编码的总体发展方向和语音编码的应用领域,才能更好地将语音编码技术应用到通信领域中。     

基于DHMM和VQ的关键词识别系统研究

针对现有关键词识别系统采用很难用硬件电路准确描述的连续隐马尔可夫模型CHMM作为识别模型,提出用离散隐马尔可夫模型DHMM作为系统的识别模型,研究了适用于硬件实现的状态机端点检测算法,并通过引入VQ矢量量化模块来保证离散关键词识别系统的识别率和识别速度;根据关键词训练模型,分析所采集语音信息中是否存在指定的关键词并进行准确识别。实验结果表明,该算法在便于硬件实现的基础上,具有良好的识别率和实时性,为关键词识别系统的FPGA硬件电路实现研究提供了参考。     

基于语音质量参数的语音传输信道检测算法

针对不同编码算法对语音质量的影响,采用语音质量改进参数构造特征矢量,提出了一种基于SVM多级判决的语音编码检测算法,实现了对不同信道的识别。采用统计方法对这组参数的区分性进行了分析,在此基础上设计了一种高效的信道检测方案,结合实际数据,测试了算法性能,并分析了语音长度对性能的影响。实验结果表明,该算法能有效地提高信道检测准确率。     

多位朝鲜语数字语音识别方法的研究

针对朝鲜语数字串语音识别中单位符号容易被误判为数字的问题,提出了基于朝鲜语数字串结构特点的识别方法．首先,对事先采集好的语音样本提取特征并存储成数字模板和单位符模板;其次,将数字串测试样本切分成孤立的数字或单位符并提取特征参数;最后,根据朝鲜语数字串发音特点,即若前1个孤立词已被识别为数字,那么后1个被默认为单位符并且只与存储单位符号的模板进行匹配．实验结果表明,该方法不仅可以获得较高的正确识别率,同时提高了识别效率．     

远程报警装置的设计与实现

针对在现场无人的情况下,可能出现的火灾、盗窃、煤气泄漏等警情设计一个以单片机为控制核心的远程自动报警装置.该装置利用传感器检测警情信息并通过无线收发模块发送给控制器,通过语音模块和DTMF双音频解码电路,能够按优先级预设的手机或座机号码自动循环拨打,在电话接通后利用语音提示实现远程报警,将警情及时准确地告知主人,有效地避免了事故的发生和扩大.     

噪声背景下语音识别特征参数选择研究

为提高语音识别系统的实用性与实时性,该文采用缺失特征分量的方法研究了美尔频率倒谱系数静态特征及其一阶差分各分量对识别率的影响.在不同信噪比情况下,分别对含白噪声、粉红噪声、车载噪声和工厂噪声这四种典型噪声的语音进行了实验研究,结果表明:在保证系统有较高识别率的情况下,在低信噪比时,含白噪声的语音信号缺失美尔频率倒谱系数...     

Adaptive bands filter bank optimized by genetic algorithm for robust speech recognition system

Perceptual auditory filter banks such as Bark-scale filter bank are widely used as front-end processing in speech recognition systems. However, the problem of the design of optimized filter banks that provide higher accuracy in recognition tasks is still open. Owing to spectral analysis in feature extraction, an adaptive bands filter bank (ABFB) is presented. The design adopts flexible bandwidths and center frequencies for the frequency responses of the filters and utilizes genetic algorithm (GA) to optimize the design parameters. The optimization process is realized by combining the front-end filter bank with the back-end recognition network in the performance evaluation loop. The deployment of ABFB together with zero-crossing peak amplitude (ZCPA) feature as a front process for radial basis function (RBF) system shows significant improvement in robustness compared with the Bark-scale filter bank. In ABFB, several sub-bands are still more concentrated toward lower frequency but their exact locations are determined by the performance rather than the perceptual criteria. For the ease of optimization, only symmetrical bands are considered here, which still provide satisfactory results.     

A speech enhancement algorithm to reduce noise and compensate for partial masking effect

To enhance the speech quality that is degraded by environmental noise,an algorithm was proposed to reduce the noise and reinforce the speech.The minima controlled recursive averaging(MCRA) algorithm was used to estimate the noise spectrum and the partial masking effect which is one of the psychoacoustic properties was introduced to reinforce speech.The performance evaluation was performed by comparing the PESQ(perceptual evaluation of speech quality) and segSNR(segmental signal to noise ratio) by the propos...     

基于免疫优化多输出最小二乘支持向量机及其应用*

传统的支持向量机是一种两类问题的判别方法, 不能直接应用于多类分类问题。为了解决这个问题,提出了一种免疫优化多输出最小二乘支持向量机方法。该方法利用免疫算法来优化最小二乘支持向量机的参数。将该方法应用于污水生化处理过程建模及语音情感识别,仿真结果表明,该方法具有更高的精度。     

一种基于分而治之的语音识别错误纠正方案*

介绍了一种基于分而治之的语音识别错误纠正方案,首先利用混淆网络把连续语音识别问题转换为顺序的、独立的分类子任务。每个分类子任务可看做是孤立词识别问题,通过训练专门的支持向量机来区分混淆网络的识别候选。提出了一种快速的基于码本转换的语音向量对齐方法,解决了变长语音向量无法直接作为支持向量机输入的问题。通过一个普通话音节识别任务的实验结果表明,该方案能有效提高系统的正确率。