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Re: Objective intelligibility measurements

Matt, have you considered the STMI out of Shihab Shamma's lab? It
accounts for both spetral and temporal characteristics. You can take a
look at:

Chi et al, J. Acoust. Soc. Am. 106(5) 2719, 1999.
Elhilali et al, Speech Communication 41(2003) 331-348.
Chi et al, J. Acoust. Soc. Am. 118(2), 2005.

Hope it helps


On Mon, Sep 15, 2008 at 5:25 AM, Matthew Reynolds
<matthew.reynolds@xxxxxxxxxx> wrote:
> Hi all,
> I am in need of a bit of advice regarding objective measures of
> intelligibility such as the AI and the STI. I am interested in assessing
> comparative intelligibility of 2 communication systems in noise with regard
> to their frequency spectra, however the systems in question use vocoder type
> codecs to transmit/recreate the speech, introducing non linear distortion
> that the above mentioned methods do not account for. However, my proposal is
> this; my signal path in both systems involves CELP algorithms and therefore
> a direct comparison using AI or STI to assess the intelligibility is not
> valid, however, it should be possible to gain a score for each system with
> no additive noise, then repeat the tests with additive noise in the acoustic
> interface (i.e. in the room with the loudspeaker, so not passing through the
> electronic signal path, algorithms etc) and see which system 'survives' the
> noise better with respect to its AI/STI score. This seems to be a valid
> approach in gaining an idea as to which system will perform better in
> acoustic noise, although obviously will not produce 'absolute' results for
> each system.
> Ideally I'd like to do this with AI as it involves measuring signal to noise
> ratios in 1/3 octave bands, something which I can readily do, whereas to
> implement an STI measurement will require purchasing some (probably
> expensive) software.
> Thanks in advance for your help
> Matt Reynolds