WIERSTORF2013
Sound localization in wavefield synthesis

Usage:

[...] = wierstorf2013(X,Y,phi,xs,src,L,method,...);

Input parameters:

`X`	range of the x-axis [xmin,xmax] or a single point x / m
`Y`	range of the y-axis [ymin ymax] or a single point y / m
`phi`	orientation of the listener in rad (0 is in the direction of the x-axis)
`xs`	position of the point source in m / direction of the plane wave
`src`	source type `ps` for a point source `pw` for a plane wave
`L`	length/diameter of the loudspeaker array
`method`	reproduction setup `wfs` for wave field synthesis `setreo` for stereophony

Output parameters:

`localization_error`
	deviation from the desired direction, defined as perceived_direction - desired_direction / degree
`perceived_direction`
	the direction of arrival the binaural model has estimated for our given setup / degree
`desired_direction`
	the desired direction of arrival indicated by the source position xs / degree
`x`	corresponding x-axis
`y`	corresponding y-axis
`x0`	position and directions of the loudspeakers in the form n x 7, where n is the number of loudspeakers

Description:

wierstorf2013(X,Y,phi,xs,src,L,method) calculates the localization error for the defined wave field synthesis or stereophony setup. The localization error is defined here as the difference between the perceived direction as predicted by the dietz2011 binaural model and the desired direction given by xs. The loudspeaker setup for the desired reproduction method is simulated via HRTFs which are than convolved with white noise which is fed into the binaural model.

The following parameters may be passed at the end of the line of input arguments:

`'resolution',resolution`
	Resolution of the points in the listening area. Number of points is resoluation x resolution. If only one point in the listening area is given via single values for X and Y, the resolution is automatically set to 1.
`'nls',nls`	Number of loudspeaker of your WFS setup. Default value is 2.
`'array',array`	Array type to use, could be 'linear' or 'circle'. Default value is 'linear'.
`'hrtf',hrtf`	HRTF database in SOFA format. Default HRTF set is the 3m one from TU-Berlin measured with the KEMAR.
`'lookup',lookup`	Lookup table to map ITD values to angles. This can be created by the `itd2angle_lookuptable` function. Default value is the lookup table `itd2angle_lookuptable.mat` that comes with AMT.

For the simulation of the wave field synthesis or stereophony setup this functions depends on the Sound-Field-Synthesis Toolbox, which is available here: http://github.com/sfstoolbox/sfs. It runs under Matlab and Octave. The revision used to generate the figures in the corresponding paper was a8914700a4. This one uses a newer version (>=2.4), but should return very similar results.

References:

M. Dietz, S. D. Ewert, and V. Hohmann. Auditory model based direction estimation of concurrent speakers from binaural signals. Speech Communication, 53(5):592--605, 2011. [ DOI ]

H. Wierstorf, M. Geier, A. Raake, and S. Spors. A free database of head-related impulse response measurements in the horizontal plane with multiple distances. In Proceedings of the 130th Convention of the Audio Engineering Society, 2011.

H. Wierstorf, A. Raake, and S. Spors. Binaural assessment of multi-channel reproduction. In J. Blauert, editor, The technology of binaural listening, chapter 10. Springer, Berlin--Heidelberg--New York NY, 2013.