% short reference
@Mastersthesis{diemo98-short,
  AUTHOR    = {D. Schwarz},
  TITLE     = "{\emph{Spectral Envelopes in Sound Analysis and Synthesis}}",
  TYPE      = {{Diplomarbeit Nr. 1622}},
  SCHOOL    = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik},
  YEAR      = {1998},
}

% full reference
@Mastersthesis{diemo98,
  AUTHOR    = {Diemo Schwarz},
  TITLE     = "{Spectral Envelopes in Sound Analysis and Synthesis}",
  TYPE      = {{Diplomarbeit Nr. 1622}},
  SCHOOL    = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik},
  ADDRESS   = {Stuttgart, Germany},
  MONTH     = jun,
  YEAR      = {1998},
  url       = {http://www.ircam.fr/equipes/analyse-synthese/schwarz/da/},
  official-url = {http://www.informatik.uni-stuttgart.de/cgi-bin/ncstrl_rep_view.pl?/inf/ftp/pub/library/medoc.ustuttgart_fi/DIP-1622/DIP-1622.bib},

  abstract = {
In this project, Spectral Envelopes in Sound Analysis and Synthesis,
various methods for estimation, representation, file storage,
manipulation, and application of spectral envelopes to sound synthesis
were evaluated, improved, and implemented.  A prototyping and testing
environment was developed, and a function library to handle spectral
envelopes was designed and implemented.

For the estimation of spectral envelopes, after defining the
requirements, the methods LPC, cepstrum, and discrete cepstrum were
examined, and also improvements of the discrete cepstrum method
(regularization, stochastic (or probabilistic) smoothing, logarithmic
frequency scaling, and adding control points).  An evaluation with a
large corpus of sound data showed the feasibility of discrete cepstrum
spectral envelope estimation.

After defining the requirements for the representation of spectral
envelopes, filter coefficients, spectral representation, break-point
functions, splines, formant representation, and high resolution
matching pursuit were examined.  A combined spectral representation
with indication of the regions of formants (called fuzzy formants) was
defined to allow for integration of spectral envelopes with precise
formant descriptions.  For file storage, new data types were defined
for the Sound Description Interchange Format (SDIF) standard.

Methods for manipulation were examined, especially interpolation
between spectral envelopes, and between spectral envelopes and
formants, and other manipulations, based on primitive operations on
spectral envelopes.  For sound synthesis, application of spectral
envelopes to additive synthesis, and time-domain or frequency-domain
filtering have been examined.

For prototyping and testing of the algorithms, a spectral envelope
viewing program was developed.  Finally, the spectral envelope
library, offering complete functionality of spectral envelope
handling, was developed according to the principles of software
engineering.
},
}