BAUMGARTNER2013 - Model for sound localization in sagittal planes

Usage

pmv = baumgartner2013( target,template )
[pmv,respang,tang] = baumgartner2013(target,template,u,lat,flow,fhigh,stim,fsstim,polsamp)

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 formated according to the following matrix dimensions: time x direction x channel/ear
`template`	listener-specific template. Options 1 & 2 equivalent to target

Output parameters

`pmv`	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 in the given sagittal plane

baumgartner2013(...) 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.

baumgartner2013 accepts the following key/value pairs:

`'fs',fs`	Define the sampling rate of the impulse responses. Default value is 48000 Hz.
`'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.
`'lat',lat`	Set the perceived lateral angle of the target sound to lat. Default value is 0 deg (midsagittal plane).
`'u',u`	Set the listener-specific uncertainty (standard deviation of the Gaussian transformation from the distance metric of the comparison process to the similarity index) to u. Default value is 2 dB.
`'space',s`	Set spacing of auditory filter bands to s numbers of equivalent rectangular bandwidths (ERBs). Default value is 1 ERB.
`'bwsteep',bws`	Set the steepness factor bws of the sigmoid function applied for binaural weighting of monaural similarity indices. Default value is 13 deg.
`'polsamp',ps`	Define the the polar angular sampling of the current SP. As default the sampling of ARI's HRTF format along the midsagittal plane is used, i.e., \(ps = [-30:5:70,80,100,110:5:210]\).

baumgartner2013 accepts the following flags:

`'gammatone'`	Use the Gammatone filterbank for peripheral processing. This is the default.
`'langendijk2002_spectralanalysis'`
	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.

Requirements:

SOFA API from http://sourceforge.net/projects/sofacoustics for Matlab (in e.g. thirdparty/SOFA)
Data in hrtf/baumgartner2013

References:

P. Majdak, R. Baumgartner, and B. Laback. Acoustic and non-acoustic factors in modeling listener-specific performance of sagittal-plane sound localization. Front Psychol, 5(319):pages not available yet, doi:10.3389/fpsyg.2014.00319, 2014. [ DOI ]

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, pages 93--119. Springer-Verlag GmbH, 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, 1987.