Topics in Acoustic Echo and Noise Control: Selected Methods for the Cancellation of Acoustical Echoes, the Reduction of Background Noise, and Speech Processing

Description

In this book, an international team of highly qualified experts treats important topics in "Acoustic Echo and Noise Control" and report the latest developments. Methods for enhancing the quality of transmitted speech signals are gaining growing attention in universities and in industrial development laboratories.

This book is organized in five parts: Part I gives a short introduction to acoustic echo and noise control. Part II deals with multi-microphone processing. In Part III, advanced methods for both linear and nonlinear echo cancellation are presented, and techniques for intelligent control of hands-free telephones are introduced. Part IV is devoted to noise reduction procedures. An in-depth treatment of conventional and of advanced methods is given, followed by a model based approach using Kalman filters. Finally, in Part V, selected applications of acoustic echo and noise control as well as speech and audio processing in general are outlined. Topics such as auditory scene analysis, wave field synthesis for spatial sound reproduction, in-car communication systems, and hearing aids are treated.

Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .XV
Part I Introduction
1 Acoustic Echo and Noise Control – Where did we come
from and where are we going?
E. H‥ansler, G. Schmidt
1.1 The Journey to Maturity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 State of the Art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.3 Outline of this Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Part II Multi-Microphone Processing
2 Joint Optimization of Acoustic Echo Cancellation and
Adaptive Beamforming
W. Herbordt, W. Kellermann, S. Nakamura
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2 Concepts for Joint Acoustic Echo Cancellation and Adaptive
Beamforming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.3 Joint Optimization of Acoustic Echo Cancellation and Adaptive
Beamforming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.5 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
VIII Contents
3 Blind Source Separation of Convolutive Mixtures of Audio
Signals in Frequency Domain
S. Makino, H. Sawada, R. Mukai, S. Araki
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.2 Blind Source Separation for Convolutive Mixtures . . . . . . . . . . . . . . . 53
3.3 Overview of Frequency-Domain Approach . . . . . . . . . . . . . . . . . . . . . . 55
3.4 Complex-Valued Independent Component Analysis . . . . . . . . . . . . . . 58
3.5 Separation Mechanism of Blind Source Separation . . . . . . . . . . . . . . . 60
3.6 Source Localization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.7 Permutation Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.8 Scaling Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.9 Spectral Smoothing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.10 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.11 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4 Localization and Tracking of Acoustical Sources
G. Doblinger
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
4.2 Source Localization Using the Generalized Cross-Correlation
Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
4.3 Source Localization Based on Interaural Time Differences . . . . . . . . 97
4.4 Source Localization Using Adaptive Filters . . . . . . . . . . . . . . . . . . . . . 103
4.5 Some Remarks on Algorithm Selection . . . . . . . . . . . . . . . . . . . . . . . . . 110
4.6 Frequency-Domain Adaptive Beamformer with Speaker Tracking . . 111
4.7 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Part III Echo Cancellation
5 Adaptive Algorithms for the Identification of Sparse
Impulse Responses
J. Benesty, Y. Huang, J. Chen, P. A. Naylor
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
5.2 Notation and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
5.3 Sparseness Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
5.4 The NLMS, PNLMS, and IPNLMS Algorithms . . . . . . . . . . . . . . . . . . 130
5.5 Universal Criterion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
5.6 Exponentiated Gradient Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
5.7 The Lambert W Function Based Gradient Algorithm . . . . . . . . . . . . 140
5.8 Some Important Links Among Algorithms . . . . . . . . . . . . . . . . . . . . . . 141
5.9 Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
5.10 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Contents IX
6 Selective-Tap Adaptive Algorithms for Echo Cancellation
P. A. Naylor, A. W. H. Khong
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
6.2 Sequential and Periodic Tap Selection . . . . . . . . . . . . . . . . . . . . . . . . . . 157
6.3 MMax Tap Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
6.4 Selective Partial Update Tap Selection . . . . . . . . . . . . . . . . . . . . . . . . . 166
6.5 Performance Comparison for Single-Channel Selective-Tap
algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
6.6 Convergence Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
6.7 Sparse Partial Update NLMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
6.8 multichannel Selective-Tap Algorithms for Stereophonic Acoustic
Echo Cancellation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
6.9 Exclusive Maximum Tap Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
6.10 Exclusive Maximum Adaptive Filters . . . . . . . . . . . . . . . . . . . . . . . . . . 190
6.11 SAEC Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
6.12 Discussion and Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
A Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
7 Nonlinear Acoustic Echo Cancellation
F. K‥uch, W. Kellermann
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
7.2 Nonlinear Acoustic Echo Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
7.3 Volterra Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
7.4 Power Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
7.5 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
8 Intelligent Control Strategies for Hands-Free Telephones
C. Breining, A. Mader
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
8.2 Fuzzy Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
8.3 Learning Vector Quantization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
8.4 Prerequisites for Automatic Optimization of Control Algorithms:
Optimum Step Size and Cost Function . . . . . . . . . . . . . . . . . . . . . . . . . 282
8.5 Radial Basis Function Network for Step-Size Control . . . . . . . . . . . . . 288
8.6 Radial Basis Function Network for State Detection . . . . . . . . . . . . . . 305
Part IV Noise Reduction
9 Noise Reduction
U. Heute
9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
9.2 Optimum-Filter Design in the Time Domain . . . . . . . . . . . . . . . . . . . . 329
X Contents
9.3 Wiener-Filter Description in the Frequency Domain. . . . . . . . . . . . . . 332
9.4 Examples and Filtering Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
9.5 Wiener-Filter Realizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
9.6 Spectral Subtraction: Principles and Realization . . . . . . . . . . . . . . . . . 339
9.7 Noise Power Density Spectrum Estimation . . . . . . . . . . . . . . . . . . . . . . 343
9.8 Subtraction and Weighting Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
9.9 Spectral Analysis and Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
9.10 System Configurations, Experiments, and Comparisons . . . . . . . . . . . 367
9.11 Further Problems and Ideas, Concluding Remarks . . . . . . . . . . . . . . . 376
10 Noise Reduction with Kalman-Filters for Hands-Free Car
Phones Based on Parametric Spectral Speech and Noise
Estimates
H. Puder
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385
10.2 Speech and Car Noise Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
10.3 Theoretical Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
10.4 Application of Kalman Filters for Noise Reduction . . . . . . . . . . . . . . . 404
10.5 Comparison of the Results with Classical Frequency Domain
Noise Reduction Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
10.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
Part V Selected Applications
11 Evaluation of Algorithms for Speech Enhancement
P. Dreiseitel, G. Schmidt
11.1 The Focus of this Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
11.2 Objective Tests for Noise Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . 432
11.3 Comparison Mean Opinion Scores (CMOS) . . . . . . . . . . . . . . . . . . . . . 449
11.4 Rhyme Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
11.5 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
12 An Auditory Scene Analysis Approach to Monaural
Speech Segregation
G. Hu, D.L. Wang
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
12.2 Computational Auditory Scene Analysis . . . . . . . . . . . . . . . . . . . . . . . . 488
12.3 Peripheral Analysis and Feature Extraction . . . . . . . . . . . . . . . . . . . . . 490
12.4 Auditory Segmentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497
12.5 Voiced Speech Grouping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 499
12.6 Unvoiced Speech Grouping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
12.7 Concluding Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
Contents XI
13 Wave Field Synthesis Techniques for Spatial Sound
Reproduction
R. Rabenstein, S. Spors, P. Steffen
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
13.2 Elements from the Foundations of Acoustics . . . . . . . . . . . . . . . . . . . . 518
13.3 Wave Field Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527
13.4 Implementation of a Wave Field Synthesis System . . . . . . . . . . . . . . . 540
13.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
14 Signal Processing for In-Car Communication Systems
G. Schmidt, T. Haulick
14.1 Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
14.2 Signal Processing for Intercom Systems . . . . . . . . . . . . . . . . . . . . . . . . 560
14.3 Evaluation of Intercom Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
14.4 A Real System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592
14.5 Conclusions and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596
15 Applications of Adaptive Signal Processing Methods in
High-End Hearing Aids
V. Hamacher, E. Fischer, U. Kornagel, H. Puder
15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
15.2 Directional Microphones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600
15.3 Noise Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
15.4 Multi-Band Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617
15.5 Feedback Cancellation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 620
15.6 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627
15.7 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637