BAUMGARTNER2014 - Model for localization in saggital planes

Usage

[p,respang] = baumgartner2014( target,template )
[p,respang,tang] = baumgartner2014( target,template )
[p,respang,tang] = baumgartner2014( target,template,fs,S,lat,stim,fsstim )

Input parameters

`target`	binaural impulse response(s) referring to the directional transfer function(s) (DFTs) of the target sound(s).
`template`	binaural impulse responses of all available listener-specific DTFs of the sagittal plane referring to the perceived lateral angle of the target sound

Output parameters

`p`	predicted probability mass vectors for response angles with respect to target positions 1st dim: response angle 2nd dim: target angle
`respang`	polar response angles (after regularization of angular sampling)
`tang`	polar target angles (usefull if sagittal-plane HRTFs are extracted directly from SOFA object)

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.

baumgartner2014 accepts the following optional 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.
`'lat',lat`	Set the apparent lateral angle of the target sound to lat. Default value is 0° (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.
`'conGain',cg`	Set the contralateral gain cg of the sigmoid function applied for binaural weighting of monaural similarity indices. Default value is 13 degrees.
`'polsamp',ps`	Define the the polar angular sampling of the current SP. As default the sampling of ARI's HRTF format at the median SP is used, i.e., ps = [-30:5:70,80,100,110:5:210] degrees.
`'mrsmsp',mrs`	Set the motoric response scatter mrs within the median sagittal plane. Default value is 17° in accordance with scatter of unimodal response distribution proposed in Langendijk and Bronkhorst (2002).

baumgartner2014 accepts the following flags:

`'gammatone'`	Use the Gammatone filterbank for peripheral processing. This is the default.
`'cqdft'`	Use a filterbank approximation based on DFT with constant relative bandwidth for peripheral processing. This was used by Langendijk and Bronkhorst (2002).
`'ihc'`	Incorporate the transduction model of inner hair cells used by Dau et al. (1996). This is the default.
`'noihc'`	Do not incorporate the IHC stage.
`'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.

References:

R. Baumgartner. Modeling sagittal-plane sound localization with the application to subband-encoded head related transfer functions. Master's thesis, University of Music and Performing Arts, Graz, June 2012. [ .pdf ]

R. Baumgartner, P. Majdak, and B. Laback. Assessment of Sagittal-Plane Sound Localization Performance in Spatial-Audio Applications, chapter 4, page expected print date. Springer-Verlag GmbH, accepted for publication, 2013.

T. Dau, D. Pueschel, and A. Kohlrausch. A quantitative model of the effective signal processing in the auditory system. I. Model structure. J. Acoust. Soc. Am., 99(6):3615-3622, 1996a.

E. Langendijk and A. Bronkhorst. Contribution of spectral cues to human sound localization. J. Acoust. Soc. Am., 112:1583-1596, 2002.

R. Patterson, I. Nimmo-Smith, J. Holdsworth, and P. Rice. An efficient auditory filterbank based on the gammatone function. APU report, 2341, 1988.