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Self-adaptive sound echo cancellation method based on frequency domain Kalman filtering

An echo cancellation and self-adaptive technology, applied in voice analysis, instruments, etc., can solve the problems of high computational complexity of the frequency-domain Kalman filter algorithm and the inability of the frequency-domain Kalman filter algorithm to converge to the optimal solution, etc., to achieve a good Echo cancellation effect, algorithm performance improvement, performance improvement effect

Active Publication Date: 2018-11-13
NANJING UNIV
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Problems solved by technology

However, the computational complexity of the standard form of the frequency-domain Kalman filter algorithm is relatively high
In addition, under the same condition that the filter order is insufficient or the system does not satisfy the causality, the frequency domain Kalman filtering algorithm cannot guarantee to converge to the optimal solution

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  • Self-adaptive sound echo cancellation method based on frequency domain Kalman filtering
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  • Self-adaptive sound echo cancellation method based on frequency domain Kalman filtering

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Embodiment Construction

[0027] In order to improve the effect of echo cancellation, the present invention analyzes the structure of frequency-domain Kalman filtering algorithm, improves the algorithm structure according to the analysis, and the specific process is as follows:

[0028] 1. Kalman filter based on frequency domain in the acoustic echo cancellation model

[0029] If the signal of the near-end microphone at the nth sampling point in the time domain is d(n), define the microphone signal vector d(k) in the time domain, which can be expressed as

[0030] d(k)=[d(kN-N+1),d(kN-N+2),...,d(kN)] T (1)

[0031] In the formula, (·) T Represents the transpose, N represents the filter length, and k represents the sequence number of the frame. Then the microphone signal can be expressed as the sum of echo signal and background noise, namely

[0032] d(k)=y(k)+s(k) (2)

[0033] y(k) and s(k) represent the echo signal and the background noise respectively, here it is assumed that the background noi...

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Abstract

The invention discloses a self-adaptive sound echo cancellation method based on frequency domain Kalman filtering. The method comprises the following specific steps: (1) collecting and caching a near-end microphone signal and a reference signal, and converting an analog signal into a digital signal through analog-digital conversion; (2) carrying out discrete Fourier transform on the digital signal, and calculating an estimated echo signal; (3) carrying out iteration according to an iterative formula of the frequency domain Kalman filter, and calculating a filter coefficient of the next frame according to an improved formula; and (4) carrying out inverse discrete Fourier transform on echo signal estimation in the frequency domain to obtain echo signal estimation of the time domain, and subtracting the echo signal estimation of the time domain from the near-end microphone signal, thus obtaining the signal after the sound echo cancellation processing. According to the method disclosed bythe invention, the optimal solution can be converged even under the condition that the order of a self-adaptive filter is insufficient or the system does not meet the causality, and a good echo cancellation effect is obtained.

Description

technical field [0001] The invention relates to an adaptive acoustic echo cancellation method based on frequency-domain Kalman filtering, and belongs to the technical field of speech enhancement. Background technique [0002] Acoustic echo is a common problem that plagues communication systems, reducing the intelligibility of speech and disrupting the communication between callers. The purpose of acoustic echo cancellation is to use reference signals to synthesize echoes, and to use synthesized signals to remove or reduce the adverse effects of acoustic echoes. [0003] The acoustic echo cancellation method based on the LMS algorithm is the most commonly used method (Sondhi M M. An Adaptive Echo Canceller [J]. Bell Labs Technical Journal, 1967, 46 (3): 497-511.). However, the acoustic echo cancellation method based on the LMS algorithm has high computational complexity, and the algorithm convergence speed is slow when the reference signal is a colored signal. [0004] The ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L21/0208
CPCG10L21/0208G10L2021/02082
Inventor 范文之卢晶
Owner NANJING UNIV
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