An algorithm for the solution of the linear equations for the "covariance method" of linear prediction is stated and proved. The algorithm requires only O(p 2 ) arithmetic operations, and in form resembles t...
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An algorithm for the solution of the linear equations for the "covariance method" of linear prediction is stated and proved. The algorithm requires only O(p 2 ) arithmetic operations, and in form resembles the Levinson algorithm for solution of the linear equations for the "correlation method" of linear prediction. The structural properties of the problem and its solution are emphasized in the analysis presented.
The broad-band (2-18 GHz) optimum steps of a commercial sliding load have been determined by simulation on a digital computer. The influence of the load, which is slided, is taken into account. The results have been t...
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The broad-band (2-18 GHz) optimum steps of a commercial sliding load have been determined by simulation on a digital computer. The influence of the load, which is slided, is taken into account. The results have been tested through a sliding short and by measuring a very good fixed load. An equivalent directivity greater than 59 dB has been obtained.
This paper considers the problem of comparing two sets of (LPC) coefficients or, more generally, that of comparing two short segments of speech via LPC techniques. It is shown that Itakura's prediction-residual ra...
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This paper considers the problem of comparing two sets of (LPC) coefficients or, more generally, that of comparing two short segments of speech via LPC techniques. It is shown that Itakura's prediction-residual ratio is intuitively unsatisfactory and theoretically misleading as a distance measure. Two slower, but more accurate statistical means of comparison are suggested, and these are supported by evidence from a simulation study.
The autocorrelation and covariance methods are the two most popular analysis techniques for linear predictive coding of speech. Recent work on the covariance method has utilized the Cholesky decomposition for solving ...
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A subjective evaluation of seven pitch detectors has been carried out using synthetic speech. The evaluation is intended to complement the objective performance evaluation of the same pitch detection algorithms in the...
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A subjective evaluation of seven pitch detectors has been carried out using synthetic speech. The evaluation is intended to complement the objective performance evaluation of the same pitch detection algorithms in the investigation of Rabiner et al. [1]. In the earlier study, each of the seven algorithms was evaluated on the basis of its performance with respect to four different types of errors. The standard of comparison was a semiautomatically determined pitch contour of each utterance in the experimental corpus. In the present study, the quality of LPC (linear predictive coding) analyzed and synthesized speech was evaluated. The pitch contour used in the synthesis was obtained either from one of the seven pitch detectors or from the semiautomatic pitch analysis. Using a computer-controlled sort board, an experiment was run in which each of eight listeners was asked to rank the nine versions of each utterance (the natural version was included to provide a stable anchor point). Results are presented on the overall preference for each pitch detector. In addition, subject preference as a function of the pitch range of the speaker and the transmission environment used in the recording is discussed. The present results are compared to those obtained in the earlier objective performance study.
We present an efficient algorithm for determining fundamental frequency and voiced/unvoiced (V/UV) decision of speech. The pitch extractor utilizes the cross-correlation average magnitude difference function (AMDF) wa...
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We present an efficient algorithm for determining fundamental frequency and voiced/unvoiced (V/UV) decision of speech. The pitch extractor utilizes the cross-correlation average magnitude difference function (AMDF) waveform that is obtained from the linear prediction residual signal. The decision logic used in pitch extraction is simple and reliable. The periodicity and null depth of AMDF waveforms, together with the average residual energy and the past pitch information, are used in the decision logic for fundamental frequency and V/UV decision. Computer simulation of the algorithm yielded accurate results, even for difficult phonemes for pitch extraction.
This paper introduces a new computational algorithm for the partial correlation coefficients of a linear system given the covariance of its output when excited by a white input noise. Although derived from Levinson...
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This paper introduces a new computational algorithm for the partial correlation coefficients of a linear system given the covariance of its output when excited by a white input noise. Although derived from Levinson's well-known procedure, the proposed algorithm does not make use of the usual parameters in the linear prediction recursion. It may be implemented using fixed point arithmetics. Application to speech waves is emphasized.
A polynomial discriminant function is used to establish the probability density function for voice/unvoice/silence parts of speech. Based on these densities, segmentation accuracy of 95% were obtained. Voice segments ...
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A polynomial discriminant function is used to establish the probability density function for voice/unvoice/silence parts of speech. Based on these densities, segmentation accuracy of 95% were obtained. Voice segments are further segmented into phonemic units using threshold functions based on energy and first formant changes (80% accuracy). Multi-dimensional probability density functions based on LPC, energy, and zero crossing serves as prototype for each phonemic unit. Prototypes are also establish for a set of phoneme-pairs. Bayes' rule is used to assign probabilities for each phoneme and phoneme-pair in the unknown speech. Word Recognition is achieved by finding the word with the highest score for its phonemic units.
This paper examines the effectiveness of parametric representation of speech derived from the linear prediction model using the new concept of composite reference for speaker verification. In the proposed verification...
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This paper examines the effectiveness of parametric representation of speech derived from the linear prediction model using the new concept of composite reference for speaker verification. In the proposed verification system the combined information of the identity of several speakers is given. That is, the existence of an overall reference contour is assumed which contains the information corresponding to the identities of several speakers in a given population. The verification task consists of authenticating an individual's claimed identity by an LPC analysis of his speech. A time warping procedure based strictly on correlation also has been incorporated. Automatic verification based on the predictor and parcor coefficients and using composite reference yielded a verification accuracy of about 96 percent.
This paper introduces a new method for the computation of the partial correlation coefficients from the autocorrelation sequence. Derived from Levinson's algorithm, it involves the calculation of the crosscorrelat...
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This paper introduces a new method for the computation of the partial correlation coefficients from the autocorrelation sequence. Derived from Levinson's algorithm, it involves the calculation of the crosscorrelations between the inputs and the outputs of the successive models which are formed. Using these, a fixed-point implementation is found for real time speech analysis on a 16-bits microprocessor. The method also gives an approximation of the impulse response of the system, which may be useful for identification with moving average models.
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