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Noise suppression method and equipment

A technology of noise suppression and noise variance, applied in speech analysis, instruments, etc., can solve the problems of large computing burden on terminal equipment, inability to have both computational complexity and processing effect, and large computational complexity

Active Publication Date: 2012-07-11
LEADCORE TECH
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Problems solved by technology

However, from the calculation factors above, it can be seen that the calculation complexity is very large, involving Bessel functions, and a table lookup operation or an approximate formula is required to replace it. Assuming that the table lookup method is used, ten multiplications are required (division is replaced by multiplication ), three additions, one square root and one exponent (the gamma function is a fixed value), which bring a great computational burden to the terminal equipment
[0014] It can be seen that in the calculation of the existing noise suppression factor, usually the computational complexity and the processing effect cannot be achieved at the same time

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Embodiment Construction

[0037] The first embodiment of the present invention relates to a noise suppression method, and the specific process is as follows figure 1 Shown.

[0038] In step 110, the noise variance is calculated by analyzing the noisy speech stream. Specifically, the noisy speech stream is usually y(t)=x(t)+d(t). x(t) represents a clean speech signal, and d(t) represents a noise signal. Analyzing the noisy speech stream refers to performing FFT (Fast Fourier Transform) on the noisy speech stream to decompose the noisy speech stream into frequency-domain spectral signals. Then, according to the formula Calculate the noise variance. among them, Represents the noise variance of the k-th frequency point in the nth frame, the subscript N represents noise, D n [k] represents the short-time Fourier spectrum (complex number) of the noise signal d(t) at the kth frequency point in the nth frame, and E{} represents the expectation.

[0039] Next, in step 120, according to the calculated noise var...

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Abstract

The invention relates to voice processing, and particularly discloses a noise suppression method and equipment. In the invention, a noise suppression factor is calculated according to a formula, n refers to frame number, k refers to absolute radio frequency channel number, Gn[k] refers to the noise suppression factor of the kth frequency point in the nth frame, (gamma)n[k] refers to the posterior signal-to-noise ratio of the kth frequency point in the nth frame, (xi)n[k] refers to the priori signal-to-noise ratio of the kth frequency point in the nth frame, and lambda refers to an exponential factor. No musical tone exists in the processed residual noise, and the calculation complexity is greatly reduced, so that the noise is simply and efficiently suppressed.

Description

Technical field [0001] The present invention relates to speech processing, in particular to noise suppression technology in speech processing. Background technique [0002] When noise suppression is performed on noisy speech streams, frequency domain processing is usually adopted, and the suppression process is achieved by multiplying the frequency points of noisy speech streams by a suppression factor: [0003] X′ n [k]=G n [k]Y n [k], k=0, 1, 2, ..., M-1 [0004] X′ n [k] is the spectrum of the suppression result of the kth frequency point of the nth frame, G n [k] is the inhibitory factor, Y n k] is the noisy speech stream spectrum at the k-th frequency point of the nth frame, and M is the number of FFT points. [0005] Currently, the following two methods are usually used to calculate the noise suppression factor: [0006] (1) Spectral-Subtract: Spectral-Subtract is the best variance estimator under the maximum likelihood (MaximumLikelihood) criterion, using To obtain the noise su...

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Application Information

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IPC IPC(8): G10L21/02G10L19/02G10L21/0232
Inventor 谢单辉叶斌朱鉴彰
Owner LEADCORE TECH
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