Speech recognition apparatus, speech recognition method, and storage medium

A speech recognition method of recognizing an input speech as a recognized speech, comprising the steps of:

• a feature extracting step of extracting feature amounts from the input speech;
• a preliminary word-selecting step of selecting words on the basis of the feature amounts by referring to a first database;
• a matching step of calculating acoustic and linguistic scores for the selected words and forming a word string serving as a candidate for the recognized speech by referring to a second database;
• wherein the second database incorporates more precise acoustic model, phoneme information, and grammar rules than the first database;
• a control step of generating word-connection-information between words in the word string;
• the word-connection-information including acoustic and linguistic scores for each word in the word string;
• a re-evaluation step of re-evaluating the word string and correcting the word-connection-information by referring to a third database;
• wherein the third database incorporates more precise acoustic models, phoneme information, and grammar rules than the second database;
• and
• a second control step of determining the recognized speech by correcting the word string on the basis of the corrected word-connection-information.

A recording medium for storing a program which executes on a computer for recognizing an input speech as a recognized speech, the program comprising:

• a feature extracting step of extracting feature amounts from the input speech;
• a preliminary word-selecting step of selecting words on the basis of the feature amounts by referring to a first database;
• a matching step of calculating acoustic and linguistic scores for the selected words and forming a word string serving as a candidate for the recognized speech by referring to a second database;
• wherein the second database incorporates more precise acoustic model, phoneme information, and grammar rules than the first database;
• a control step of generating word-connection-information between words in the word string;
• the word-connection-information including acoustic and linguistic scores for each word in the word string;
• a re-evaluation step of re-evaluating the word string and correcting the word-connection-information by referring to a third database;
• wherein the third database incorporates more precise acoustic models, phoneme information, and grammar rules than the second database;
• and
• a second control step of determining the recognized speech by correcting the word string on the basis of the corrected word-connection-information.