Design of Circular Differential Microphone Arrays (eBook)
IX, 166 Seiten
Springer International Publishing (Verlag)
978-3-319-14842-7 (ISBN)
Recently, we proposed a completely novel and efficient way to design differential beamforming algorithms for linear microphone arrays. Thanks to this very flexible approach, any order of differential arrays can be designed. Moreover, they can be made robust against white noise amplification, which is the main inconvenience in these types of arrays. The other well-known problem with linear arrays is that electronic steering is not really feasible.
In this book, we extend all these fundamental ideas to circular microphone arrays and show that we can design small and compact differential arrays of any order that can be electronically steered in many different directions and offer a good degree of control of the white noise amplification problem, high directional gain, and frequency-independent response. We also present a number of practical examples, demonstrating that differential beamforming with circular microphone arrays is likely one of the best candidates for applications involving speech enhancement (i.e., noise reduction and dereverberation). Nearly all of the material presented is new and will be of great interest to engineers, students, and researchers working with microphone arrays and their applications in all types of telecommunications, security and surveillance contexts.
Abstract 6
Contents 7
1 Introduction 10
1.1 Introduction 10
1.2 General Principles of Microphone Arrays 11
1.3 From Linear Differential Arrays to Circular Differential Arrays 19
1.4 Organization of the Book 20
References 21
2 Problem Formulation 23
2.1 Signal Model 23
2.2 Beampattern 27
2.3 Gain in Signal-to-Noise Ratio (SNR) 34
References 38
3 Design of First-Order Circular Differential Arrays 40
3.1 Principle 40
3.2 Design Examples 43
3.2.1 First-Order Dipole 43
3.2.2 First-Order Cardioid 46
3.2.3 General First-Order Circular Differential Array 49
References 59
4 Design of Second-Order Circular Differential Arrays 60
4.1 Principle and Design Examples with Four Microphones 60
4.1.1 Second-Order Dipole 61
4.1.2 Second-Order Cardioid 64
4.1.3 Second-Order Hypercardioid 67
4.1.4 Second-Order Supercardioid 70
4.2 Principle and Design Examples with Five Microphones 73
4.2.1 Second-Order Dipole 74
4.2.2 Second-Order Cardioid 78
4.2.3 Second-Order Hypercardioid 81
4.2.4 Second-Order Supercardioid 84
References 87
5 Design of Third-Order Circular Differential Arrays 88
5.1 Principle and Design Example with Six Microphones 88
5.2 Principle and Design Example with Seven Microphones 92
5.3 Generalization 96
References 97
6 Superdirective Beamforming with Circular Arrays 98
6.1 Superdirective Beamforming with ULAs 98
6.2 Superdirective Beamforming with UCAs 100
6.2.1 Without the Symmetry Constraint 101
6.2.2 With the Symmetry Constraint 103
6.2.3 With the Maximum of Nulls 105
6.3 Design Examples 105
6.3.1 Superdirective Beamforming with a ULA 105
6.3.2 Superdirective Beamforming with a UCA –without the Symmetry Constraint 106
6.3.3 Superdirective Beamforming with a UCA – with the Symmetry Constraint 112
6.3.4 Superdirective Beamforming with a UCA – with the Maximum of Nulls 114
References 118
7 Minimum-Norm Solution for Robust Circular Differential Arrays 119
7.1 Adaptive Beamforming versus Circular Differential Arrays 119
7.2 Minimum-Norm Filter 122
7.3 Design Examples 123
7.3.1 First-Order Cardioid 124
7.3.2 Second-Order Cardioid 130
7.3.3 Third-Order Cardioid 136
7.3.4 Third-Order Pattern with Three Distinct Nulls 142
References 147
8 Design of Circular Differential Arrays with the Jacobi-Anger Expansion 149
8.1 Beampattern Definitions Revisited 149
8.2 Design Principle 152
8.3 First-Order Differential Arrays 153
8.4 Second-Order Differential Arrays 155
8.5 Third-Order Differential Arrays 157
8.6 Adaptive Beamforming versus Differential Arrays 165
8.7 Design of the Ideal Beampattern 169
References 170
Index 171
Erscheint lt. Verlag | 24.1.2015 |
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Reihe/Serie | Springer Topics in Signal Processing |
Zusatzinfo | IX, 166 p. 102 illus., 100 illus. in color. |
Verlagsort | Cham |
Sprache | englisch |
Themenwelt | Technik ► Elektrotechnik / Energietechnik |
Schlagworte | Cardioid • Circular Differential Microphone Arrays • Differential Beamforming • Dipole • Directivity Factor • Directivity Pattern • Hypercardioid • Supercardioid • Superdirective Beamforming • White Noise Gain |
ISBN-10 | 3-319-14842-7 / 3319148427 |
ISBN-13 | 978-3-319-14842-7 / 9783319148427 |
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