THE AUDITORY MODELING TOOLBOX

Applies to version: 1.6.0

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BAUMGARTNER2014
Localization in saggital planes (robust, linear periphery)

Usage:

[p,rang] = baumgartner2014( target,template )
[p,rang,tang] = baumgartner2014( target,template )
[p,rang,tang] = baumgartner2014( target,template, varargin )
[err,pred] = baumgartner2014( target,template,errorflag )

Input parameters:

target binaural impulse response(s) referring to the directional transfer function(s) (DFTs) of the target sound(s). Option 1: given in SOFA format -> sagittal plane DTFs will be extracted internally. Option 2: binaural impulse responses of all available listener-specific DTFs of the sagittal plane formatted according to the following matrix dimensions: time x direction x channel/ear
template binaural impulse responses of all available listener-specific DTFs of the sagittal plane referring to the perceived lateral angle of the target sound. Options 1 & 2 equivalent to target.

Output parameters:

p predicted probability mass vectors for response angles with respect to target positions 1st dim: response angle 2nd dim: target angle
rang polar response angles (after regularization of angular sampling)
tang polar target angles (usefull if sagittal-plane HRTFs are extracted directly from SOFA object)
err predicted localization error (acc. to performance measure defined in errorflag
pred structure with fields p, rang, tang

Description:

baumgartner2014(...) is a model for sound-source localization in sagittal planes (SPs). It bases on the comparison of internal sound representation with a template and results in a probabilistic prediction of polar angle response.

Additional input parameters:

'fs',fs Define the sampling rate of the impulse responses. Default value is 48000 Hz.
'S',S Set the listener-specific sensitivity threshold (threshold of the sigmoid link function representing the psychometric link between transformation from the distance metric and similarity index) to S. Default value is 1.
'gamma',G Set the degree of selectivity (slope of the sigmoid link function representing the psychometric link between transformation from the distance metric and similarity index) to G. Default value is 6.
'lat',lat Set the apparent lateral angle of the target sound to lat. Default value is 0 degree (median SP).
'stim',stim Define the stimulus (source signal without directional features). As default an impulse is used.
'fsstim',fss Define the sampling rate of the stimulus. Default value is 48000 Hz.
'flow',flow Set the lowest frequency in the filterbank to flow. Default value is 700 Hz.
'fhigh',fhigh Set the highest frequency in the filterbank to fhigh. Default value is 18000 Hz.
'space',sp Set spacing of auditory filter bands (i.e., distance between neighbouring bands) to sp in number of equivalent rectangular bandwidths (ERBs). Default value is 1 ERB.
'do',do Set the differential order of the spectral gradient extraction to do. Default value is 1 and includes restriction to positive gradients inspired by cat DCN functionality.
'bwcoef',bwc Set the binaural weighting coefficient bwc. Default value is 13 degrees.
'tang',tang Only for input option 2: Define the target's polar-angle sampling of the acoustic data provided for the current sagittal plane. Information required to compute error metrics. As default the sampling of ARI's HRTFs in the median SP is used, i.e., tang = [-30:5:70,80,100,110:5:210] degrees.
'polsamp',ps Only for input option 2: Define the template's polar-angle sampling of the acoustic data provided for the current sagittal plane. See 'tang' for default sampling.
'rangsamp',rs Define the equi-polar sampling of the response predictions. The default is rs = 5 degrees.
'mrsmsp',eps Set the motoric response scatter eps within the median sagittal plane. Default value is 17 degrees.

baumgartner2014 accepts the following flags:

'regular' Apply spline interpolation in order to regularize the angular sampling of the polar response angle. This is the default.
'noregular' Disable regularization of angular sampling.
'errorflag' May be one of the error flags defined in baumgartner2014_pmv2ppp or localizationerror.

Requirements:

  1. SOFA API from http://sourceforge.net/projects/sofacoustics for Matlab (in e.g. thirdparty/SOFA)
  2. Data in auxdata/baumgartner2014
  3. Circular Statistics Toolbox from http://www.mathworks.com/matlabcentral/fileexchange/10676-circular-statistics-toolbox--directional-statistics-

References:

R. Baumgartner, P. Majdak, and B. Laback. Modeling sound-source localization in sagittal planes for human listeners. The Journal of the Acoustical Society of America, 136(2):791--802, 2014. [ DOI ]

R. Lyon. All pole models of auditory filtering. In E. R. Lewis, G. R. Long, R. F. Lyon, P. M. Narins, C. R. Steele, and E. Hecht-Poinar, editors, Diversity in auditory mechanics, pages 205--211. World Scientific Publishing, Singapore, 1997.