We recently proposed a multichannel audio coding method using a multiband source/filter model, which results in a compact representation of the original recording. Our method can reproduce the original recording using...
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We recently proposed a multichannel audio coding method using a multiband source/filter model, which results in a compact representation of the original recording. Our method can reproduce the original recording using only one audio channel and side information for the remaining channels in the order of 5 KBps/channel. Here, we examine packet loss concealment strategies for use within our model, so that we can derive a complete system for low-bitrate multichannel audio streaming through the Internet or wireless channels.
This paper proposes a new vector quantization method which can reduce search complexity and code book memory size by reducing the number of code vectors without increasing quantization distortion. This method uses hyp...
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This paper proposes a new vector quantization method which can reduce search complexity and code book memory size by reducing the number of code vectors without increasing quantization distortion. This method uses hypercolumnar clusters;and an input vector is quantized to a cluster, the center axis of which is nearest to the input vector. Thus, one vector and one scalar must be coded and transmitted. The proposed method was applied to four geometrically different distributions and LPC cepstra of speech signals. As a result, the number of code vectors was decreased compared with that in an ordinary vector quantizer, in all of the forementioned distributions. Then the reduction of memory size and search complexity were evaluated. The excessive bits required for the scalar quantization in this method also were studied.
The paper presents a new depth-based view blending technique that avoids the problem of different fields of view corresponding to the input views that are used for synthesis of a virtual view. The idea consists in usi...
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The paper presents a new depth-based view blending technique that avoids the problem of different fields of view corresponding to the input views that are used for synthesis of a virtual view. The idea consists in using the depth associated with the input views in order to increase the quality of the finally blended view. The experiments, performed on high quality multi-view test sequences, show that the proposed method significantly improves the quality of synthesized views in systems with non-linearly arranged cameras.
Though vector quantizers are more efficient than scalar quantizers, their use for fine quantization of linear predictive coding (LPC) information (using 24-26 b/frame) is impeded due to their prohibitively high comple...
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Though vector quantizers are more efficient than scalar quantizers, their use for fine quantization of linear predictive coding (LPC) information (using 24-26 b/frame) is impeded due to their prohibitively high complexity. In the present work, a split vector quantization approach is used to overcome the complexity problem. The LPC vector, consisting of ten line spectral frequencies (LSFs), is divided into two parts and each part is quantized separately using vector quantization. Using the localized spectral sensitivity property of the LSF parameters, a weighted LSF distance measure is proposed. Using this distance measure, it is shown that the split vector quantizer can quantize LPC information in 24 b/frame with 1-dB average spectral distortion and <2% outlier frames (having spectral distortion greater than 2 dB).< >
The fixed-lag smoothing problem with a partial lag is the problem in which the presence of the smoothing lag is allowed only in a part of estimation channels. This paper studies the effect of a partial smoothing lag o...
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The fixed-lag smoothing problem with a partial lag is the problem in which the presence of the smoothing lag is allowed only in a part of estimation channels. This paper studies the effect of a partial smoothing lag on the achievable H ∞ performance in the continuous-time case. In particular, the limit of the achievable performance is established and the saturation of the achievable performance for a finite smoothing lag is analyzed.
We present a novel speech encryption algorithm based on blind source separation (BSS). Our approach integrates a modified time domain scrambling scheme with an amplitude scrambling method which masks the speech signal...
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ISBN:
(纸本)0780386477
We present a novel speech encryption algorithm based on blind source separation (BSS). Our approach integrates a modified time domain scrambling scheme with an amplitude scrambling method which masks the speech signal with a random noise by specific mixing. The resulting system can securely encrypt the speech files for the purpose of storing speech messages and transmitting them over the Internet. There are two major advantages associated with this system. The first advantage is that it makes the encrypted speech sound like white noise. The second advantage is that it does not impose any restriction on the key space. Our system is systematically evaluated, and it shows a high level of security with excellent audio quality.
In this paper we introduce an efficient probabilistic neural networks (PNN) model-based voice activity detection (VAD) algorithm. The inputs for PNN are code excited linear prediction coder parameters, which are stabl...
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In this paper we introduce an efficient probabilistic neural networks (PNN) model-based voice activity detection (VAD) algorithm. The inputs for PNN are code excited linear prediction coder parameters, which are stable under background noise. The PNN network output is 1 or 0 to determine the nature of the period (speech or Nonspeech). Experimental results show that the proposed VAD algorithm achieves better performance than G.729 Annex B at any noise level. The performance compares very favorably with Adaptive MultiRate VAD, phase 2 (AMR2).
The non-linear nature of low-rate parametric speech coding has made it necessary to resort to formal subjective assessments for quantifying end-to-end voice quality of interconnected networks. At the same time, the ra...
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The non-linear nature of low-rate parametric speech coding has made it necessary to resort to formal subjective assessments for quantifying end-to-end voice quality of interconnected networks. At the same time, the rapid growth of cellular communications has highlighted the need to characterize transmission quality when cellular terminals are attached at the access or termination nodes of switched networks. In the paper the voice quality of interconnected North-American and Japanese digital cellular systems over public transmission facilities is quantified. From these assessments it is concluded that cellular networks using 8 kbit/s or 6.4 kbit/s VSELP may meet end-to-end quantization distortion criteria when interconnected with the switched network.
A suitable metric to characterize subjective speech quality is the mean opinion score (MOS). For a given test condition, its subjective rating is obtained for every trail as a numeric value in the following manner: Un...
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A suitable metric to characterize subjective speech quality is the mean opinion score (MOS). For a given test condition, its subjective rating is obtained for every trail as a numeric value in the following manner: Unsatisfactory=1; Poor=2; Fair=3; Good=4; and Excellent=5. The arithmetic average of these ratings over all trails constitutes the MOS of the given test condition. The measurement of MOS and the subjective quality results obtained for a specific 12 kb/s subband coder are reported.< >
Cochlear implants are an effective way to enable people with severe or profound hearing loss to be able to hear. It can help a person with profound hearing loss to function with people and places where hearing may be ...
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Cochlear implants are an effective way to enable people with severe or profound hearing loss to be able to hear. It can help a person with profound hearing loss to function with people and places where hearing may be required. Cochlear implants are a fine solution for severe to profound hearing loss, but there are problems that may accrue, and other solutions that need to be considered before a person makes the decision to get a cochlear implant for his or herself or a loved one
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