×

Real time computer speech recognition system

  • US 4,852,170 A
  • Filed: 12/18/1986
  • Issued: 07/25/1989
  • Est. Priority Date: 12/18/1986
  • Status: Expired due to Fees
First Claim
Patent Images

1. A real time speech recognition system comprising:

  • means for receiving audio speech signals and for converting them into corresponding electrical signals having a predetermined maximum frequency of interest;

    analog-to-digital conversion means for sampling said signals at a rate at least twice as high as said maximum frequency;

    spectrum analyzer means for accepting sets of samples from said analog-to-digital converter extending over a time interval of between about two milliseconds and about sixteen milliseconds, and for providing a digital spectrum analysis of each of said sets of samples;

    means for logically analyzing said sets of samples, and for classifying the series of samples into silence, transitions, and phonemes of at least the following classes;

    (1) voiced stops, (2) unvoiced stops, (3) unvoiced fricatives, (4) vowels, semi-vowels, and voiced fricatives, and (5) transitions;

    means for mathematically analyzing the relationships between the formants of the classified phonemes to uniquely identify successive phonemes;

    said analyzing means including means for defining phoneme regions wherein, in the graphical analysis of a first one of said formants plotted against an other one of said formants at least some selected boundaries of the defined regions extend over both a range of first format frequencies and a range of said other formant frequencies, and for determining the coordinates defined by the formants of each phoneme, and the region in which such coordinates fall, thereby identifying each phoneme;

    means for forming sequences of continuous strings of phonemes, eliminating transitions and silences;

    means for translating the strings of phonemes into the words of a language;

    said means for translating strings of phonemes into a language including means for parsing the phoneme string, including (1) determining alternative correct possible words from the phoneme string, (2) eliminating those alternatives which Yield subsequent non-words in the following phoneme string, and (3) selecting the remaining alternative word; and

    means for printing out text corresponding to the translated words.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×