Sensor Array Directional Response Simulator

Simulate responses for sensor arrays of arbitrary geometry and directional characteristics.

# Sensor Array Response Simulator
#### A library that simulates array responses for sensors with arbitrary geometry and directional characteristics.
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> Archontis Politis, 2015
> Department of Signal Processing and Acoustics, Aalto University, Finland
> [e-mail]
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This Matlab/Octave library was developed during my doctoral research in the [Communication Acoustics Research Group] (http://spa.aalto.fi/en/research/research_groups/communication_acoustics/), Aalto University, Finland. If you would like to reference the code, you can refer to my dissertation published [here](https://aaltodoc.aalto.fi/handle/123456789/22499):

Archontis Politis, Microphone array processing for parametric spatial audio techniques, 2016
Doctoral Dissertation, Department of Signal Processing and Acoustics, Aalto University, Finland

## Description

This is a collection of MATLAB routines for simulation of array responses of

a) directional sensors and,

b) sensors mounted on, or at a distance from, a rigid spherical/cylindrical
scatterer.

The computation of their frequency and impulse responses is
based on the theoretical expansion of a scalar incident plane wave field to
a series of wavenumber-dependent Bessel-family functions and
direction-dependent Fourier or Legendre functions.

A function for arbitrary open arrays of directional microphones is included
not based on the expansion but directly on the steering vector formula of
inter-sensor delays and sensor gains for directional patterns
(e.g. arrays of cardioid microphones).

Most of the functionality of the library is displayed in the included
script TEST_ARRAY_SIMULATOR.m

For more information on the expansions, you can have a look on

Earl G. Williams, "Fourier Acoustics: Sound Radiation and Nearfield
Acoustical Holography", Academic Press, 1999

Heinz Teutsch, "Modal Array Signal Processing: Principles and
Applications of Acoustic Wavefield Decomposition", Springer, 2007

and for example on
[http://en.wikipedia.org/wiki/Plane_wave_expansion] and
[http://en.wikipedia.org/wiki/Jacobi-Anger_expansion]

For any questions, comments, corrections, or general feedback, please
contact [e-mail]

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For more details on using functions, check their help output in Matlab.

### List of MATLAB files:

* sph_besselj.m : Various spherical Bessel-family functions and their
* sph_bessely.m : derivatives, for the computation of the radial
* sph_function.m : terms of the expansions (modal weights)
* sph_hankel1.m
* sph_hankel2.m
* dbesselj.m
* dbessely.m
* dhankel1.m
* dhankel2.m
* dsph_besselj.m
* dsph_bessely.m
* dsph_function.m
* dsph_hankel1.m
* dsph_hankel2.m

* simulateCylArray.m : Simulate cylindrical open arrays or arrays of sensors mounted on a rigid cylinder
* simulateSphArray.m : Simulate spherical open arrays or arrays of sensors mounted on a rigid sphere
* cylModalCoeffs.m : Compute the radial (modal) weights for a cylindrical scatterer
* sphModalCoeffs.m : Compute the radial (modal) weights for a spherical scatterer

* sphericalScatterer.m : Compute the response for a measurement point at an arbitrary distance from a rigid spherical scatterer
* cylindricalScatterer.m : Compute the response for a measurement point at an arbitrary distance from a rigid cylindrical scatterer

* getArrayResponse.m' : Simulate open arrays of arbitrary directional microphones with axisymmetric responses