Apparatus system and method for speech compression and decompression
First Claim
1. A method for processing a speech signal comprising steps of:
- identifying a plurality of portions of said speech signal representing individual speech pitches;
generating an encoded speech signal from a plurality of said speech pitches, said encoded speech signal retaining ones of said plurality of pitches and omitting other ones of said plurality of pitches, at least one speech pitch being omitted for each speech pitch retained; and
generating a reconstructed speech signal by replacing each said omitted pitch with an interpolated replacement pitch having signal waveform characteristics which are interpolated from a first retained reference pitch occurring temporally earlier to said pitch to be interpolated and from a second retained reference pitch occurring temporally later than said pitch to be interpolated.
11 Assignments
0 Petitions
Accused Products
Abstract
The invention provides system, apparatus, and method for compressing a speech signal by decimating or removing somewhat redundant portions of the signal while retaining reference signal portions sufficient to reconstruct the signal without noticeable loss in quality, thereby permitting a storage and transmission of high quality speech with minimal storage volume or transmission bandwidth requirements. Speech pitch waveform decimation is used to reduce data to produce an encoded speech signal during compression, and time based interpolative speech reconstruction is used on the encoded signal to reconstruct the original speech signal. In one aspect, the invention provides a method for processing a speech signal that includes identifying portions of the speech signal representing individual speech pitches; generating an encoded speech signal from the speech pitches, the encoded speech signal retaining ones of the plurality of pitches and omitting other ones of the plurality of pitches; and generating a reconstructed speech signal by replacing each the omitted pitch with an interpolated replacement pitch having signal waveform characteristics which are interpolated from a first retained reference pitch occurring temporally earlier to the pitch to be interpolated and from a second retained reference pitch occurring temporally later than the pitch to be interpolated. In another aspect apparatus is provided to perform the speech compression and reconstruction method. In another aspect an internet voice electronic mail system is provided which has minimal voice message storage and transmission requirements while retaining high fidelity voice quality.
111 Citations
19 Claims
-
1. A method for processing a speech signal comprising steps of:
-
identifying a plurality of portions of said speech signal representing individual speech pitches; generating an encoded speech signal from a plurality of said speech pitches, said encoded speech signal retaining ones of said plurality of pitches and omitting other ones of said plurality of pitches, at least one speech pitch being omitted for each speech pitch retained; and generating a reconstructed speech signal by replacing each said omitted pitch with an interpolated replacement pitch having signal waveform characteristics which are interpolated from a first retained reference pitch occurring temporally earlier to said pitch to be interpolated and from a second retained reference pitch occurring temporally later than said pitch to be interpolated. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A speech processor for processing a speech signal, said speech processor comprising:
-
a plurality of delay circuits, each receiving said speech signal f(t) as an input and generating a different time delayed version of said speech signal f(t-Tdi) as an output; a plurality of correlator circuits, each said correlator circuit receiving said input speech signal f(t) and one of said time delayed speech signals f(t-Tdi) and generating a correlation value indicating the amount of correlation between said speech signal f(t) and said time delayed speech signal; a comparator circuit receiving said plurality of correlation values and generating an autocorrelation of said input signal with time delayed versions of said speech signal, one correlation value being received from each of said correlator circuits; a pitch detector receiving said autocorrelation signal and identifying a pitch length for at least a portion of said speech signal; and an encoder receiving said pitch length and said speech signal and generating an encoded version of said speech signal wherein speech pitches of said speech signal are retained or omitted on the basis of said pitch detector input. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
-
-
15. An electronic voice mail system for communicating an original speech signal message between a first computer and a second computer among a plurality of networked computers, said system said characterized in that:
-
said first computer system includes a first speech processor operative to generate a compressed encoded speech signal; said second computer system includes a second speech processor operative to generate a decompressed reconstructed speech signal from said encoded signal; said first speech processor comprising; a plurality of delay circuits, each receiving said speech signal f(t) as an input and generating a different time delayed version of said speech signal f(t-Tdi) as an output; a plurality of correlator circuits, each said correlator circuit receiving said input speech signal f(t) and one of said time delayed speech signals f(t-Tdi) and generating a correlation value indicating the amount of correlation between said speech signal f(t) and said time delayed speech signal; a comparator circuit receiving said plurality of correlation values and generating an autocorrelation of said input signal with time delayed versions of said speech signal, one correlation value being received from each of said correlator circuits; a pitch detector receiving said autocorrelation signal and identifying a pitch length for at least a portion of said speech signal; and an encoder receiving said pitch length and said speech signal and generating an encoded version of said speech signal wherein speech pitches of said speech signal are retained or omitted on the basis of said pitch detector input; and said second speech processor comprising; a decoder receiving said encoded speech signal generated by said first speech processor, including receiving a plurality of reference pitches; and interpolation means for interpolating pitches occurring temporally between said reference pitches to generate a reconstructed version of said original speech signal. - View Dependent Claims (18, 19)
-
-
16. A voice transmission system for communicating an original speech signal message over a low-bandwidth communications channel between a transmitting location and a receiving location, said system said characterized in that:
-
said transmitting location includes a first processor adapted to generate a compressed encoded speech signal; said first processor comprising; a signal delay processor receiving said original speech signal f(t) as an input and generating a plurality of different time delayed versions of said speech signal f(t-Tdi) as outputs; a signal correlator receiving said original speech signal f(t) and said time delayed speech signals f(t-Tdi), i=1, . . . , n and generating correlation values indicating the amount of correlation between said speech signal f(t) and said time delayed speech signals; a comparator receiving said correlation values and generating an autocorrelation result of said input signal with time delayed versions of said speech signal; a pitch detector receiving said autocorrelation signal and identifying a pitch length for at least a portion of said speech signal; and an encoder receiving said pitch length and said original speech signal and generating an encoded version of said speech signal wherein speech pitches of said speech signal are retained or omitted on the basis of said pitch detector input. - View Dependent Claims (17)
-
Specification