PhD A: How about you , Carmen ?
PhD D: Well , I am still working with , eh , VTS . And , one of the things that last week , eh , say here is that maybe the problem was with the diff because the signal have different level of energy .
Professor B: Hmm ?
PhD D: And , maybe , talking with Stephane and with Sunil , we decide that maybe it was interesting to to apply on - line normalization before applying VTS . But then we decided that that 's it doesn't work absolutely , because we modified also the noise . And Well , thinking about that , we we then we decide that maybe is a good idea . We don't know . I don't hav I don't this is I didn't do the experiment yet to apply VTS in cepstral domain .
Professor B: The other thing is So so , in i i and Not and C - zero would be a different So you could do a different normalization for C - zero than for other things anyway . I mean , the other thing I was gonna suggest is that you could have two kinds of normalization with with , uh , different time constants . So , uh , you could do some normalization s uh , before the VTS , and then do some other normalization after . I don't know . But but C - zero certainly acts differently than the others do ,
PhD D: Uh .
Professor B: so that 's PhD C: Mm - hmm .
PhD D: Well , we s decide to m to to obtain the new expression if we work in the cepstral domain . And Well . I am working in that now ,
Professor B: Uh - huh .
PhD D: but I 'm not sure if that will be usefu useful . I don't know . It 's k it 's k It 's quite a lot It 's a lot of work .
Professor B: Uh - huh .
PhD D: Well , it 's not too much , but this it 's work .
Professor B: Yeah .
PhD D: And I want to know if if we have some feeling that the result I I would like to know if I don't have any feeling if this will work better than apply VTS aft in cepstral domain will work better than apply in m mel in filter bank domain . I r I 'm not sure . I don't I don't know absolutely nothing .
PhD C: Mm - hmm .
Professor B: Yeah . Well , you 're I think you 're the first one here to work with VTS , so , uh , maybe we could call someone else up who has , ask them their opinion . Uh ,
PhD C: Mm - hmm .
Professor B: I don't I don't have a good feeling for it . Um .
PhD G: Pratibha .
PhD C: Actually , the VTS that you tested before was in the log domain and so the codebook is e e kind of dependent on the level of the speech signal .
PhD D: Yeah ?
PhD C: And So I expect it If if you have something that 's independent of this , I expect it to it to , uh , be a better model of speech .
PhD D: To have better PhD C: And . Well .
Professor B: You you wouldn't even need to switch to cepstra . Right ? I mean , you can just sort of normalize the PhD C: No . We could normali norm I mean , remove the median .
Professor B: Yeah . Yeah . And then you have one number which is very dependent on the level cuz it is the level ,
PhD D: Mm - hmm .
Professor B: and the other which isn't .
PhD C: Mm - hmm . Yeah . But here also we would have to be careful about removing the mean of speech and not of noise .
PhD D: Ye
PhD C: Because it 's like first doing general normalization
PhD D: Yea
PhD C: and then noise removal , which is PhD D: Yeah . We I was thinking to to to estimate the noise with the first frames and then apply the VAD ,
Professor B: Mm - hmm .
PhD C: Mm - hmm .
PhD D: before the on - line normalization .
PhD C: Mm - hmm .
PhD D: We we see Well , I am thinking about that and working about that ,
Professor B: Yeah .
PhD D: but I don't have result this week .
Professor B: Sure . I mean , one of the things we 've talked about maybe it might be star time to start thinking about pretty soon , is as we look at the pros and cons of these different methods , how do they fit in with one another ? Because we 've talked about potentially doing some combination of a couple of them . Maybe maybe pretty soon we 'll have some sense of what their characteristics are ,
PhD D: Mm - hmm .
Professor B: so we can see what should be combined .