Re: [Speechsc] Question on Verification Result Device type

Hello Eric,

I wasn't proposing to change anything. I just thought it would be good 
if they were described so that people new what they were. Nik gave some 
good background.

Regards, Christian

Eric Burger wrote:
> Since these are terms of art, let's not change anything.
>
> On Jun 11, 2009, at 9:59 PM, Nik Waldron wrote:
>
>> Hi Christian,
>>
>> I'm not an expert on MRCPv2 but as someone working on Verification
>> implementation and having some familiarity with the field I think that
>> this is due to the time at which MRCPv2 was originally drafted.  At that
>> time (a part of) the state of the art was an idea known as handset
>> normalisation or HNorm.  HNorm set about solving the problem that
>> different handsets had very different log likelihood ratio scores.  
>> There
>> were several variants on the solution, but basically several scores for
>> different utterances against the same voiceprint, or scores for the same
>> utterance against the different voice prints (or a combination) were 
>> used
>> to normalise the score.
>>
>> In particular the microphone type (carbon button, or electret) were 
>> major
>> categories for distorting scores, and compensating for the microphone 
>> type
>> found to be effective.  I guess that in order for the system to 
>> operate in
>> an online way (updating the sets used for normalisation), it might be
>> necessary for the results to be categorised by microphone type (if 
>> known).
>> Others more familiar with the motivations for these fields may wish to
>> correct me.
>>
>> Things have moved on a bit since then, however if you do a search 
>> (HNorm,
>> TNorm or CNorm) you should be able to find the relevant papers.  If the
>> engine you are interested in does not support / use these types of
>> normalisation or identify the categories then I'm sure 'unknown' will
>> satisfy the specification.
>>
>> Best regards,
>>
>>
>>
>>
>> NIK WALDRON
>>
>>
>>
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>