Continuous speech recognition

In a speech analysis apparatus for recognizing a plurality of keywords in an audio signal, each keyword being characterized by a template having at least one target pattern and each sequence of said keywords in said audio signal being described by a grammatical syntax, said syntax being characterized by a plurality of connected decision nodes, the recognition apparatus comprising:

• means for providing a sequence of numerical scores for recognizing keywords in said audio signal employing dynamic programming,
• means for employing said grammatical syntax for determining which scores form acceptable progressions in the recognition process, and
• means for using augments to preserve acceptable progressions whereby otherwise acceptable progressions are discarded according to said syntax.

In a speech analysis apparatus for recognizing at least one keyword in an audio signal, a method for recognizing silence in said audio signal comprising the steps of:

• generating a numerical measure of likelihood that the present incoming audio signal portion corresponds to a reference pattern representing silence,
• effectively altering the numerical measure according to a syntax dependent determination, said syntax dependent determination representing the recognition of an immediately preceeding portion of the audio signal according to a grammatical syntax, and
• determining from the effectively altered measure whether the present signal portion corresponds to silence.

In a speech analysis apparatus for recognizing at least one spoken keywork in an audio signal, each keyword being characterized by a template having at least one target pattern, a method for forming reference patterns representing said spoken keywords and tailored to a speaker, comprising the steps of:

• providing speaker independent reference patterns representing said spoken keywords,
• determining beginning and ending boundaries of said keywords in audio signals spoken by said speaker using said speaker independent reference patterns, and
• training the speech analysis apparatus to said speaker using the beginning and ending boundaries determined by said apparatus for said keywords spoken by said speaker.

In a speech analysis apparatus for recognizing at least one spoken keyword in an audio signal, each keyword being characterized by a template having at least one target pattern, a method for forming reference patterns representing a previously unknown keyword comprising the steps of:

• providing speaker independent reference patterns representing spoken keywords previously known to the apparatus,
• determining beginning and ending boundaries of said unknown keyword using said speaker independent reference patterns, and
• training the speech analysis apparatus, using the beginning and ending boundaries previously determined by said apparatus for said previously unknown keyword, to generate statistics describing said previously unknown keyword.

In a speech analysis apparatus for recognizing a plurality of keywords in an audio signal, each keyword being characterized by a template having at least one target pattern and each sequence of said keywords in said audio signal being described by a grammatical syntax, said syntax being characterized by a plurality of connected decision nodes, the recognition method comprising the steps of:

• providing a sequence of numerical scores for recognizing keywords in said audio signal employing dynamic programming,
• employing said grammatical syntax for determining which scores form acceptable progressions in the recognition process, and
• reducing the number of decision nodes by collapsing said syntax whereby the computational load for the apparatus is reduced.

In a speech analysis apparatus for recognizing a plurality of keywords in an audio signal, each keyword being characterized by a template having at least one target pattern and each sequence of said keywords in said audio signal being described by a grammatical syntax, said syntax being characterized by a plurality of connected decision nodes, the recognition method comprising the steps of:

• providing a sequence of numerical scores for recognizing keywords in said audio signal employing dynamic programming,
• employing said grammatical syntax for determining which scores form acceptable progressions in the recognition process, and
• using augments to preserve acceptable progressions whereby otherwise acceptable progressions are discarded according to said syntax.

In a speech analysis apparatus for recognizing at least one keyword in an audio signal, apparatus for recognizing silence in said audio signal comprising:

• means for generating a numerical measure of likelihood that the present incoming audio signal portion corresponds to a reference pattern representing silence,
• means for adding to the numerical measure a syntax dependent numerical value to form a score, said syntax dependent value representing the recognition of an immediately preceeding portion of the audio signal according to a grammatical syntax, and
• means for determining from the score whether the present signal portion corresponds to silence.

In a speech analysis apparatus for recognizing at least one spoken keyword in an audio signal, each keyword being characterized by a template having at least one target pattern, apparatus for forming reference patterns representing said spoken keywords and tailored to a speaker comprising:

• means for providing speaker independent reference patterns representing said spoken keywords,
• means for determining beginning and ending boundaries of said keywords in audio signals spoken by said speaker using said speaker independent reference patterns, and
• means for training the speech analysis apparatus to said speaker using the beginning and ending boundaries determined by said apparatus for said keywords spoken by said speaker.

In a speech analysis apparatus for recognizing at least one spoken keyword in an audio signal, each keyword being characterized by a template having at least one target pattern, apparatus for forming reference patterns representing a previously unknown keyword comprising:

• means for providing speaker independent reference patterns representing spoken keywords previously known to the apparatus,
• means for determining beginning and ending boundaries of said unknown keyword using said speaker independent reference patterns, and
• means for training the speech analysis apparatus using the beginning and ending boundaries previously determined by said apparatus for said unknown keyword to generate statistics describing said previously unknown keyword.

In a speech analysis apparatus for recognizing a plurality of keywords in an audio signal, each keyword being characterized by a template having at least one target pattern and each sequence of said keywords in said audio signal being described by a grammatical syntax, said syntax being characterized by a plurality of connected decision nodes, the recognition apparatus comprising:

• means for providing a sequence of numerical scores for recognizing keywords in said audio signal employing dynamic programming,
• means for employing said grammatical syntax for determining which scores form acceptable progressions in the recognition process, and
• means for reducing the number of decision nodes whereby the computational load for the apparatus is reduced.