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    Wyświetlanie 1-2 z 2
    Tytuł:
    Model-Based Method for Acoustic Echo Cancelation and Near-End Speaker Extraction: Non-negative Matrix Factorization
    Autorzy:
    Agrawal, P.
    Shandilya, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/958086.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    adaptive algorithms
    convergence
    echo cancellation
    non-negative matrix factorization (NMF)
    Opis:
    Rapid escalation of wireless communication and hands-free telephony creates a problem with acoustic echo in full-duplex communication applications. In this paper a simulation of model-based acoustic echo cancelation and near-end speaker extraction using statistical methods relying on nonnegative matrix factorization (NMF) is proposed. Acoustic echo cancelation using the NMF algorithm is developed and its implementation is presented, along with all positive, real time elements and factorization techniques. Experimental results are compared against the widely used existing adaptive algorithms which have a disadvantage in terms of long impulse response, increased computational load and wrong convergence due to change in near-end enclosure. All these shortcomings have been eliminated in the statistical method of NMF that reduces echo and enhances audio signal processing.
    Źródło:
    Journal of Telecommunications and Information Technology; 2018, 2; 15-22
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Quality assessment of speech signals under a process of echo cancelation in telecommunications systems
    Autorzy:
    Dobrucki, Andrzej
    Kin, Maurycy
    Walczyński, Maciej
    Powiązania:
    https://bibliotekanauki.pl/articles/2146665.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    DSP
    digital signal processing
    echo cancellation
    adaptive filtration
    sound perception
    cyfrowe przetwarzanie sygnałów
    kompensacja echa
    filtracja adaptacyjna
    percepcja dźwięku
    Opis:
    The phenomenon of echo in the telecommunications channels is caused by the reflection of an electrical signal in a long line. In order to improve the quality of the transmitted sound, various adaptive filters are used to remove or at least reduce the level of the reflected delayed signal. However, such a process may result in a degradation in the quality of speech, although its intelligibility may not get worse. The work presents the results of subjective studies on assessing the quality of speech signals under the process of acoustic echo cancellation using different algorithms. The algorithms studied were: LMS (Least Mean Squares), NLMS (Normalized Least Mean Squares) and AP (Affine Projection). The study consisted of assessing the signal quality after applying the echo elimination process using the Degradation Category Rating method. A total of 312 signals were used in the test: 192 male speech and 120 female speech samples. Echo simulation was used using different delay times and levels of echo signal. Both types of speech have signal delay times of 20 ms, 50 ms, 100 ms and 200 ms with echo level values of -6 dB, -12 dB, -18 dB and -24 dB. In addition, for female speech signals, a delay time of 150 ms was introduced. The study involved 14 people aged between 18 and 38, including six women and eight men. All subjects had normal good hearing. Seven listeners had participated in subjective listening tests of the sound quality assessment previously. The listeners’ opinions were collected on prepared questionnaire. It was found that the highest ratings were given to the AP filter, while the worst ratings were featured the NLMS. It should also be noted that the range between the results obtained for AP and NLMS for female speech is smaller in comparison to male. It is also interesting that the discrepancy in ratings was greatest for a delay time of 100 ms for the AP filter and 200 ms for the LMS filter. It can therefore be concluded from the obtained results that, in the case of acoustic echo cancelation, AP filter introduced the lowest quality degradation while the LMS achieved slightly worse average ratings when compared to the AP filter . The NLMS filter characterized by the worst ratings, and in some cases received twice the quality degradation compared to the AP filter.
    Źródło:
    Vibrations in Physical Systems; 2022, 33, 1; art. no. 2022111
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-2 z 2

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