Stereophonic Acoustic Echo Cancellation (SAEC)
Research and development of stereophonic echo control systems has been a subject of interest over the last 20+ years. In fact, one of the first papers describing the characteristics of stereophonic echo cancellation was presented in 1991 [1]. In this paper, it is pointed out that the loudspeaker (input) signals are linearly related through non-invertible acoustic room responses (in the case of one source, but not necessarily two or more). The consequence of this linear relationship is that the underlying normal (or Wiener-Hopf) equations to be solved by the adaptive algorithm is an ill-conditioned, or in the worst case, a singular problem. In the singular case, the adaptive filter can drift between candidates in the set of available nonunique solutions, all minimizing the variance of the output error. However, these solutions do not necessarily minimize filter misalignment. As a result, some unstable behavior for certain time varying events may be expected. Even though the problem of nonuniqueness was described, analyzed, and solutions presented in early publications, e.g., [2], [3], [4], many following proposals have been confused over what has to be done to solve the problem correctly. Fundamentally, the core solution to the stereophonic acoustic echo cancellation (SAEC) problem must tackle two issues: (a) provide a proper solution to the inherent ill-posed problem of stereophonic echo cancellation and (b) mitigate the effect that the ill-posed problem has on the convergence rate and tracking of the adaptive algorithm. The former problem (a), can only be solved by manipulating the signals actually transmitted to the near-end (receiving) room, i.e., using a preprocessor on the loudspeaker signals to decorrelate them (or more accurately to reduce the coherence) before the SAEC as well as before transmitting them to the far-end room.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Sondhi, M.M., Morgan, D.R.: Acoustic echo cancellation for stereophonic teleconferencing. In: Proc. IEEE WASPAA (1991)
Sondhi, M.M., Morgan, D.R., Hall, J.L.: Stereophonic acoustic echo cancellation–An overview of the fundamental problem. IEEE Signal Process. Lett. 2, 148–151 (1995)
Amand, F., Gilloire, A., Benesty, J.: Identifying the true echo path impulse responses in stereophonic acoustic echo cancellation. In: Proc. EUSIPCO, pp. 1119–1122 (1996)
Benesty, J., Morgan, D.R., Sondhi, M.M.: A better understanding and an improved solution to the specific problems of stereophonic acoustic echo cancellation. IEEE Trans. Speech, Audio Process. 6, 156–165 (1998)
Cioffi, J., Kailath, T.: Fast recursive-least-squares transversal filters for adaptive filtering. IEEE Trans. Acoust., Speech, Signal Process. 34, 304–337 (1984)
Bellanger, M.G.: Adaptive Filters and Signal Analysis. Marcel Dekker, New York (1988)
Bellanger, M.G., Regalia, P.A.: The FRL-QR algorithm for adaptive filtering: the case of multichannel signal. Signal Process. 22, 115–126 (1991)
Benesty, J., Amand, F., Gilloire, A., Grenie, Y.: Adaptive filtering algorithms for stereophonic acoustic echo cancellation. In: Proc. IEEE ICASSP, pp. 3099–3102 (1995)
Eneroth, P., Gay, S.L., Gänsler, T., Benesty, J.: A real-time stereophic acoustic subband echo canceler. In: Gay, S.L., Benesty, J. (eds.) Acoustic Signal Processing for Telecommunication, ch. 8, pp. 135–153. Kluwer Academic Publishers, Dordrecht (2000)
Rights and permissions
Copyright information
© 2011 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Benesty, J., Paleologu, C., Gänsler, T., Ciochină, S. (2011). Introduction. In: A Perspective on Stereophonic Acoustic Echo Cancellation. Springer Topics in Signal Processing, vol 4. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-22574-1_1
Download citation
DOI: https://doi.org/10.1007/978-3-642-22574-1_1
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-22573-4
Online ISBN: 978-3-642-22574-1
eBook Packages: EngineeringEngineering (R0)