共查询到20条相似文献,搜索用时 31 毫秒
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Ninad S. Bhatt 《International Journal of Speech Technology》2016,19(4):881-893
This paper addresses a novel approach to investigate, study and simulate computation of high band (HB) feature extraction based on linear predictive coding (LPC) and mel frequency cepstral coefficient (MFCC) techniques. Further, HB features are embedded into encoded bitstream of proposed global system for mobile (GSM) full rate (FR) 06.10 coder using joint source coding and data hiding before being transmitted to receiving terminal. At receiver, HB features are extracted to reproduce HB portion of speech and for the same different extension of excitation techniques are applied and their results evaluated in terms of quality (intelligibility and naturalness) and bandwidth. MATLAB based e-test bench is created for implementing the proposed artificial bandwidth extension (ABE) coder following series of simulations, that are carried out to discover and gain insight about the performance of it using subjective [mean opinion score (MOS)] and objective [perceptual evaluation of speech quality (PESQ)] analysis. The results obtained for both the analyses advocate that proposed ABE coder outperforms proposed GSM FR NB (legacy GSM FR) coder. While the fact remains that, compared to LPC based parameterizations over ABE coder, MFCC parameterization results in higher speech intelligibility which is evident from obtained slightly better PESQ and MOS scores. 相似文献
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Pulakka H. Laaksonen L. Vainio M. Pohjalainen J. Alku P. 《IEEE transactions on audio, speech, and language processing》2008,16(6):1124-1137
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一种DCT域的音频信息隐藏方法 总被引:6,自引:0,他引:6
基于信息隐藏技术,提出并实现了一种语音保密通信的新方法。首先将保密语音进行混合激励线性预测(MELP)编码,形成隐藏信息;然后对公开语音信号作分段DCT变换,隐藏信息通过量化处理嵌入到DCT域的中频点;解码器在同样的嵌入点盲提取出隐藏信息,最后经MELP解码恢复保密语音。实验结果表明该算法在隐藏信息后,信道中传输的公开语音具有透明性,并且在受到压缩、滤波等攻击时具有较高的鲁棒性。 相似文献
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采用步进频域能量检测法可以提高在软件无线电平台的频谱感知的带宽范围,但能量检测法易受噪声不确定性的影响,而信号采样自相关检测法对噪声不确定性有很好的鲁棒性。为进一步提高软件无线电的检测性能,提出了基于信号采样自相关的步进宽带频谱感知方法。首先阐述了信号采样自相关检测的原理,然后对基于该原理的步进宽带检测方法的流程进行了分析,最后利用MATLAB软件仿真其检测性能。仿真结果表明,在信噪比(Signal-noise-ratio, SNR)不同的情况下,基于信号采样自相关的步进宽带频谱检测方法能达到所要求的检测性能。此
外,为了兼顾频谱感知的检测速度和频带带宽分辨率之间的关系,进一步提出了在原本固定步进值的步进宽带信号采样自相关的频谱感知方法中采用可变步进值的两阶段检测方法,该方法可
以获得较高的频带带宽检测分辨率和较短的检测时间。 相似文献
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频谱感知是认知无线电的一项关键技术,其能够检测出未被主用户占用的频谱空穴,提高频谱利用率。提出两种宽带感知方法——矩形谱感知法和谱相关感知法,分别适用于已知主用户带宽和主用户功率谱(PSD)的情况。不同于以往将宽带频谱感知转换为窄带频谱感知的方法,利用主用户先验PSD在宽带范围内直接搜索主用户信号。该方法不需要带宽划分,直接在宽带内进行检测,对主用户信号PSD没有特殊要求,主用户信号可以随机出现在所检测的带宽范围内。仿真结果表明,由于谱相关法比矩形谱法利用了更多的先验信息,其检测性能优于矩形谱法,主用户载波估计更为准确。 相似文献
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Gustafsson H. Lindgren U.A. Claesson I. 《IEEE transactions on audio, speech, and language processing》2006,14(2):577-588
Today's telecommunications systems use a limited audio signal bandwidth. A typical bandwidth is 0.3-3.4 kHz, but recently it has been suggested that mobile phone networks will facilitate an audio signal bandwidth of 50 Hz-7 kHz. This is suggested since an increased bandwidth will increase the sound quality of the speech signals. Since only few telephones initially will have this facility, a method extending the conventional narrow frequency-band speech signal into a wide-band speech signal utilizing the receiving telephone only is suggested. This will give the impression of a wide-band speech signal. The proposed speech bandwidth extension method is based on models of speech acoustics and fundamentals of human hearing. The extension maps each speech feature separately. Care has been taken to deal with implementation aspects, such as noisy speech signals, speech signal delays, computational complexity, and processing memory usage. 相似文献
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为了解决现有图像信息隐藏方法未考虑图像插值而导致的图像信息隐藏效果差,以及图像信息传输的安全性低的问题,提出周期线性干扰信号的阶频谱图像信息隐藏方法。选用改进的双线性插值方法对周期线性干扰信号的阶频谱图像信息进行预处理,包括图像传输的加密与解密、概率密度函数的计算,并对秘密信息的嵌入点进行重新插值,从而为秘密信息创造更大的冗余空间,增大信息的隐藏容量。通过改变相邻像素插值的思想,计算图像水平、垂直、斜方向的嵌入式插值,实现周期线性干扰信号的阶频谱图像信息隐藏。仿真结果表明,所提方法具有较好的隐藏效果,是一种切实有效的图像信息隐藏方法。 相似文献
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针对频谱变化范围较大的宽带信号的子带分解问题,为了动态地调整子带的宽带与数量,合理地控制子带信号的自相关矩阵特征值扩散度,提高子带信号处理的性能和效率,在基于离散傅里叶变换(DFT)子带分解方法的基础上,提出了一种基于信号功率谱密度(PSD)的动态非均匀子带分解的新方法。对于给定序列,通过功率谱估计,确定子带数目和子带幅度范围,通过子带调制实现不同子带向零频处搬移,实现信号的分解。利用Matlab对子带信号特征值扩散度和信号重建性能进行了仿真。实验结果表明,与均匀子带分解相比,提出的方法直接利用PSD的分布信息实现非均匀子带分解,有效地控制了子带信号特征值扩散度在合理范围内的分布,并具有较好的重构性能。 相似文献
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Information hiding is an important method to achieve multi-media security. Recently, many researchers have paid attention to the reversible data hiding scheme, which can completely recover original multi-media files after the embedded data are extracted. In this paper, a side-match approach is proposed to achieve more capacity in histogram-based reversible data hiding for grayscale images. The histogram is created by exploiting the difference in all the values between pixels and their predictedive values. Experimental results show that our method is capable of providing a great embedding capacity without causing noticeable distortion. In one-level hiding, where it has the best capacity, our method conserves image qualities larger than 48 dB. Furthermore, in multilevel hiding, a rotation strategy is proposed to further improve image qualities. Experimental results show that our method performs better than other existing methods in multilevel hiding cases. 相似文献
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针对传统空时结构宽带波束形成器结构复杂、计算量大和稳健性差的问题,提出低复杂度的稳健宽带波束形成算法。首先给出频率变化时阵列响应相位,分析频率变化与角度变化对阵列响应相位的影响。通过对期望信号不同频点施加阵列响应幅度和相位约束,补偿不同频率间的阵列响应相位差来实现无需延迟线或FIR/IIR滤波器结构的稳健宽带波束形成。然后分析频率和角度同时变化对阵列响应相位的影响,在期望信号来向附近引入辅助方位角,进一步提高期望信号来向趋于零度和相对带宽较小时算法的稳健性。理论分析与仿真实验表明,本文算法结构简单,计算复杂度较低且具有较好的稳健性。 相似文献
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随着无线需求和无线业务的不断增加,传输信号必将不断向高速率宽带宽发展。在宽带应用中,由于传输信号带宽增加,RF功率放大器不同于窄带输入下的无记忆特性,将表现出与频率有关的记忆非线性特性。针对宽带功率放大器线性化的记忆预失真技术成为当前研究的一个热点,综述了宽带RF功率放大器的预失真线性化技术的研究进展,详细介绍和分析了目前最主要的几种记忆预失真器的模型和对应的自适应预失真方案,最后给出了今后的研究方向。 相似文献
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提出了一种基于自适应加权谱内插(STRAIGHT)的宽带语音编码算法。输入的语音信号首先经过STRAIGHT分析得到精确的基频参数和谱参数,然后通过时域抽取和频域建模实现有效的编码压缩。在时域抽取时采用的区别于传统编码算法固定帧长的自适应可变帧长方法,使得编码存储量可以根据实际语音变化情况得到更加合理的分配。主观测听结果表明,该算法针对16kHz采样的语音信号,在6kbps码率上可以取得与AMR-WB(G.722.2)在8.85kbps时的相当的音质效果。此外,该算法还具有对恢复语音的时长、基频以及谱参数较强的调整能力。 相似文献
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王彪 《计算机与数字工程》2012,40(4):19-21
为了提高语音识别率,提出了一种改进的MFCC参数提取方法。该方法应用小波包变换高分辨率的特点和语音高频加权的功能,在传统MFCC参数的基础上提取了一种新特征参数。新参数能对语音信号频率进行更加精细的划分,能够更稳定地减小频谱失真,且在一定程度上降低了信号的噪声。最后采用高斯混合模型(GMM)进行说话人语音识别,实验表明新特征参数取得了较好的识别率。 相似文献
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In this paper, we introduce a sub-Nyquist sampling-based receiver architecture and method for wideband spectrum sensing. Instead of recovering the original wideband analog signal, the proposed method aims to directly reconstruct the power spectrum of the wideband analog signal from sub-Nyquist samples. Note that power spectrum alone is sufficient for wideband spectrum sensing. Since only the covariance matrix of the wideband signal is needed, the proposed method, unlike compressed sensing-based methods, does not need to impose any sparsity requirement on the frequency domain. The proposed method is based on a multi-coset sampling architecture. By exploiting the inherent sampling structure, a fast compressed power spectrum estimation method whose primary computational task consists of fast Fourier transform (FFT) is proposed. Simulation results are presented to show the effectiveness of the proposed method. 相似文献
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一种适用于说话人识别的改进Mel滤波器 总被引:1,自引:0,他引:1
Mel倒谱系数(MFcc)侧重提取语音信号的低频信息,对语音信号的频谱分布特性描述不充分,不能有效区分说话人个性信息。为此,通过分析语音信号各频段所含说话人个性信息的不同,结合Mel滤波器和反Mel滤波器在高低频段的不同特性,提出一种适于说话人识别的改进Mel滤波器。实验结果表明,改进Mel滤波器提取的新特征能够获得比传统Mel倒谱系数以及反Mel倒谱系数(IMFCC)更好的识别效果,并且基本不增加说话人识别系统训练和识别的时间开销。 相似文献
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针对基于非负矩阵分解(non-negative matrix factorization, NMF)的语音增强方法在低信噪比部分和无结构特征的清音部分会引入失真这一问题,利用语音信号在时频域呈现的稀疏特性和深度神经网络在语音增强应用中表现出的谱重构特性,提出了一种联合稀疏非负矩阵分解和深度神经网络的单通道语音增强方法.首先对带噪语音的幅度谱进行非负矩阵分解得到与语音字典和噪声字典相对应的稀疏编码矩阵,其中语音字典和噪声字典通过对纯净语音和噪声进行训练预先得到,以维纳滤波方法恢复出语音成分的主要结构;然后利用深度神经网络在语音增强中表现出的时频保持特性,通过深层网络学习经维纳滤波分离出的语音的对数幅度谱和理想纯净语音对数幅度谱之间的非线性映射函数,进而恢复出语音结构的缺失成分.实验结果表明:所提方法可以有效抑制噪声且较好地恢复出语音成分,在语音感知质量和对数谱失真性能评价指标上均优于基线方法. 相似文献