Enhancement of speech coding in background noise for low-rate sp

Details Enhancement of speech coding in background noise for low-rate sp Enhancement of speech coding in background noise for low-rate sp

1993-05-12

1997-10-21

MacDonald, Allen R.

395 217, 395 223, G10L 900

Patent

active

056805080

ABSTRACT:
A speech coding system employs measurements of robust features of speech frames whose distribution are not strongly affected by noise/levels to make voicing decisions for input speech occurring in a noisy environment. Linear programing analysis of the robust features and respective weights are used to determine an optimum linear combination of these features. The input speech vectors are matched to a vocabulary of codewords in order to select the corresponding, optimally matching codeword. Adaptive vector quantization is used in which a vocabulary of words obtained in a quiet environment is updated based upon a noise estimate of a noisy environment in which the input speech occurs, and the "noisy" vocabulary is then searched for the best match with an input speech vector. The corresponding clean codeword index is then selected for transmission and for synthesis at the receiver end. The results are better spectral reproduction and significant intelligibility enhancement over prior coding approaches. Robust features found to allow robust voicing decisions include: low-band energy; zero-crossing counts adapted for noise level; AMDF ratio (speech periodicity) measure; low-pass filtered backward correlation; low-pass filtered forward correlation; inverse-filtered backward correlation; and inverse-filtered pitch prediction gain measure.

REFERENCES:
patent: 4074069 (1978-02-01), Tokura et al.
patent: 4091237 (1978-05-01), Wolnowsky et al.
patent: 4296279 (1981-10-01), Stork
patent: 4589131 (1986-05-01), Horvath et al.
patent: 4630304 (1986-12-01), Borth et al.
patent: 4696038 (1987-09-01), Doddington et al.
patent: 4720802 (1988-01-01), Damoulakis et al.
patent: 4933973 (1990-06-01), Porter
patent: 4975956 (1990-12-01), Liu et al.
patent: 5073940 (1991-12-01), Zinser et al.
patent: 5127053 (1992-06-01), Koch
patent: 5459814 (1995-10-01), Gupta et al.
Rabiner et al., "Digital Processing of Speech Signals," Prentice Hall, Upper Saddle River, NJ, pp. 130-133, 451-452. Dec. 1978.
Delle, Jr. et al., "Discrete-Time Processing of Speech Signals," Prentice Hall, Upper Saddle River, NJ, pp. 244-251, 471-473. Dec. 1987.
Hess W., "Pitch Determination of Speech Signals", pp. 373-383, Springer-Verlag, NY 1983.
Siegel LJ, "A Procedure for using pattern classification techniques to obtain a voiced/unvoiced classifier," IEEE Trans., ASSP-27:1, 1979.
Hess, "Pitch Determination of Speech Signals," Springer-Verlag, New York, 373-383. Dec. 1983.
Siegel, "A Procedure for Using Pattern Classification Techniques to Obtain a Voiced/Unvoiced Classifier," IEEE vol. ASSP-27, N. 1. Feb. 1979.

Affiliated with

Also associated with

Rating

Enhancement of speech coding in background noise for low-rate sp does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Enhancement of speech coding in background noise for low-rate sp, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhancement of speech coding in background noise for low-rate sp will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1013589