Patent ID: 6185528
Filing Date: 2001-02-06
Classification: G10L

Abstract:
A method for speech recognition wherein: two recognition Steps are performed, one based on the use of neural networks, and the other on the use of hidden Markov models, each step supplying a respective list of recognition hypothesis, in which each hypothesis is associated with a respective acoustic likelihood score; the likelihood scores of each list are processed; and a single list reordered on the basis of the processed scores is provided, the two recognition steps operating sequentially on a common utterance to be recognized, in such a way that the neural network step analyses the entire active vocabulary and the Markov step analyses only a partial vocabulary represented by the list of hypotheses obtained as a result of the neural network step, and in that additionally an evaluation of recognition reliability in performed for the best hypothesis of the re-ordered list, on the basis of the scores resulting from said combination and associated with such best hypothesis and to one or more hypotheses which seize subsequent positions in the re-ordered list, thereby originating a reliability index that can take up at least two values, corresponding to the cases of recognition rated as ""Certain"" or ""not certain"", respectively.