Patent ID: 7664642

Claim:
A method for executing in a computing system automatic recognition of speech comprising: providing a pre-stored knowledge base, the knowledge base including phonetic features, each of said phonetic features associated with a corresponding set of acoustic correlates; organizing in a processor said phonetic features into a hierarchy, said hierarchy including a broad manner sub-hierarchy of broad manner phonetic features and a fine phonetic feature sub-hierarchy of fine phonetic features, each of said broad manner phonetic features corresponding to a set of acoustic landmarks; providing a pattern recognizer executable for determining a phonetic feature of said hierarchy from a set of acoustic correlates provided thereto and for determining for a phonetic feature of said hierarchy a probability measure of likelihood that said provided set of acoustic correlates is associated therewith; training said pattern recognizer on said phonetic features and said each corresponding set of acoustic correlates of said knowledge base; obtaining a speech signal, said speech signal including a sequence of speech frames; extracting acoustic correlates from each frame of said sequence of speech frames; classifying said acoustic correlates into set of broad manner classes via said pattern recognizer, said broad manner classes corresponding to said broad manner phonetic features; determining locations of acoustic landmarks from said set of broad manner classes; forming a plurality of possible landmark sequences from said acoustic landmarks; computing for each possible landmark sequence a first probability measure of likelihood that said possible landmark sequence is representative of the speech; determining from said acoustic correlates of a predetermined number of speech frames proximate to each of said acoustic landmarks a corresponding fine phonetic feature of said fine phonetic feature sub-hierarchy for each of said set of broad manner classes via to said pattern recognizer; forming a plurality of possible fine phonetic feature sequences from said fine phonetic feature corresponding to each of said set of broad manner classes; computing for each possible fine phonetic feature sequence a second probability measure of likelihood that said possible fine phonetic feature sequence is representative of the corresponding possible landmark sequence; and combining a landmark sequence from said plurality of possible landmark sequences with a fine phonetic feature sequence from said plurality of possible fine phonetic feature sequences in accordance with a product of said first probability measure corresponding to said landmark sequence and said second probability measure corresponding to said fine phonetic feature sequence being among a predetermined number of maximum values of said product for all of said possible landmark sequences and all of said possible fine phonetic feature sequences.