Menu

Weighted finite state transducers.

creative64
2012-03-06
2012-09-22
  • creative64

    creative64 - 2012-03-06

    What are weighted FSTs and how they are superior for speech recognition
    compared to HMMs ? Or is it a fair
    statement to make ?

    Thanks and regards,

     
  • Nickolay V. Shmyrev

    With the uniform mathematical representation of the search space WFST
    structure allows you to efficiently compress search space with the WFST
    modification algorithms. For example you can reduce the space with WFST
    minimization and thus speed up the decoding. You can also represent lattices
    as WFST structures and thus have a simple and powerful framework for speech
    decoding, redecoding and so on.

    You can learn more from the related papers, for example from the ones listed
    on our wiki page:

    http://cmusphinx.sourceforge.net/wiki/asr:wfst

     
  • creative64

    creative64 - 2012-03-06

    Other than being efficient, do WFST techniques have any effect on recognition
    accuracy per se ?

     
  • Nickolay V. Shmyrev

    Efficiency could always be traded for accuracy

     
  • creative64

    creative64 - 2012-03-06

    So is WFST the future trend in speech recognition ? Any shortcoming of this
    new technology vis-a-vis
    HMM based technology used say in Pocketsphinx ?

    Thanks and regards,

     
  • Nickolay V. Shmyrev

    So is WFST the future trend in speech recognition?

    it's not a future trend, it's a current trend. And there are many problems in
    WFST too, it can't handle large of flexible language models. So the new
    approaches are developed too, dynamic decoders for example.

    Any shortcoming of this new technology vis-a-vis HMM based technology used
    say in Pocketsphinx ?

    You can not compare WFST vs HMM, those are technologies of a different scale.
    WFST decoder also uses HMM framework. You can compare static WFST decoder vs
    dynamic decoder like pocketsphinx like in this paper

    http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5372904

    Dynamic decoder has it's own advantages. It's like comparing compiled language
    vs interpreted language. There was quite some attentions to compiled languages
    in computer science history but recently interpreted languages like Python are
    more popular for many applications. For some applications compiled languages
    are better.

     
  • creative64

    creative64 - 2012-03-07

    Hi, Nickolay,

    Thanks a lot for the information.

    Regards,

     

Log in to post a comment.