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WU Hongwei WU Zhenyang ZHAO Li 《声学学报:英文版》2007,26(3):278-288
Multitaper spectrum has lower variance than the traditional periodogram. The noise spectrum and the noise to noisy signal spectrum ratio (NNSR) were estimated from the multitaper spectrum of the noisy signal; the pre-enhanced speech for calculating the noise masking threshold was obtained by the spectral amplitude subtraction method, whose gain is a function of NNSR; the final enhanced speech was obtained by suppressing the Fourier spectrum of the noisy speech with the psychoacoustical weighting rule incorporating the noise masking threshold. Because of the low variance feature of the multitaper spectrum, a modified offset formula was proposed to calculate the noise masking threshold, thus the reconstructed speech with this modification has an improvement in MBSD (Modified Bark Spectral Distortion). When a maximum limitation less than one to the psychoacoustical weighting rule is further proposed, the higher the input SNR (> 0 dB) is, the more improvement the segmental SNR and the overall SNR have. The informal listening tests show that there is little speech distortion for the enhanced speech processed by the proposed method, the background noise is reduced much and free of musical noise. 相似文献
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TAO Zhi ZHAO Heming GU Jihua WU Di 《声学学报:英文版》2007,26(1):63-72
Watermark embedding algorithm based on critical band wavelet transform of digital audio signal is proposed in this paper. The masking threshold for each audio signal segment was calculated on the basic of psychoacoustic model. According to the similarity between critical band of human auditory system and critical band wavelet transform, a watermark was embedded into the low-band and mid-band coefficients of digital wavelet. The embedding strength was adaptively controlled by the masking threshold. The experiment results show that the embedded watermark signal is inaudible, and the watermarked audio signal has good robustness against many attacks such as compression, noise, re-sampling, low-pass filtering. 相似文献
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虚拟现实是一种逼真地模拟人在自然环境中的视觉、听觉、运动等行为的人机界面技术。利用虚拟声的方法可产生各种不同的声音空间听觉,包括对声源的定位和对环境的声学空间特性感觉,因而在虚拟声学环境中有重要应用。由于在现实的环境中,声源和倾听者的空间位置以及周围的声学环境都可能是变化的,为了准确地模拟出这种变化,通常需要采用前面所述的包括头部位置跟踪和自适应信号处理的虚拟声系统,以根据声源、倾听者和环境的变化,实时地改变信号处理程序。这类虚拟现实的系统通常比较复杂,国外有多个实验室建有这类系统。 相似文献
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在前面我们曾说过,嗓音链的另一端为嗓声的接受与感知,即嗓声的听觉方面。在这一个专题中,我们要介绍关于听觉的三个方面。一、一些与嗓声有关的心理量和物理量的关系;二、一些重要听觉理论;三、介绍(主要是近些年来的)一些嗓声感知实验的研究结果。因为国内对于言语声的感知研究已有较多介绍,而声乐声的感知研究的文献却罕见;又因为本嗓声讲座主要对象是艺术噪声的教育、医学和工程界,我们将以介绍声乐声的感知为主。关于听觉系统的解剖生理,即人耳对声接受的通道方面这里从略。 相似文献
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1999年3月14日至19日,在德国柏林举行了第137届美国声学学会大会暨第二届欧洲声学大会(声学论坛)及第25届德国声学大会.此次国际声学联合大会是由美国声学学学会(ASA)、欧洲声学学会(EAA)、及德国声学学会(DEGA)三家共同举办的.来自世界34个国家或地区的近2000人参加了会议.分14个大主题,198个分会、收到论文1955篇.本次大会旨在推动国际声学各领域的研究,虽称地区性会议,但会议内容涉及声学的各个方面,可称本世纪最后一次全球性的声学会议.会议分的14个大主题分别为:建筑声学… 相似文献