Patent Document ID: 5583968
Application ID: 08219219
Patent Status: 1

Claim One:
1. A method for speech recognition in a noisy environment using a neural network, said method comprising the steps of: performing a training phase prior to speech recognition including: (a) combining speech-free noise signals with noise-free speech signals; (b) providing a sequence of noisy vectors in response to said combined speech-free noise signals and noise-free speech signals; (c) providing noise-free vectors indicative of said noise-free speech signals; (d) performing an iterative neural noise reduction on said noisy vectors including: (1) mapping said noisy vectors into noise-reduced vectors; (2) generating a mapping error as the difference between said noise-reduced vectors and said noise-free vectors; (3) reducing said mapping error by selecting additional information from a suitable signal representation at an input of the neural network; and (4) performing, in iterative steps, a further neural noise reduction on said noise-reduced vectors by reducing said mapping error if said mapping error is not equal to zero or can be reduced; (e) adding nodes to a topology of the neural network containing said noise-reduced vectors; and performing speech recognition from noisy speech signals including: (f) providing a sequence of noisy speech vectors in response to said noisy speech signals; (g) performing an iterative neural noise reduction on said noisy speech vectors including: (1) mapping said noisy speech vectors into noise-reduced speech vectors; (2) generating a speech mapping error as the difference between said noise-reduced speech vectors and said noise-reduced vectors contained in said nodes; (3) reducing said mapping error by selecting additional information from a suitable signal representation at said input of the neural network; (4) performing, in iterative steps, a further neural noise reduction by reducing said speech mapping error if said mapping error is not equal to zero or can be reduced; and (h) adding nodes to a topology of the neural network indicative of said noise-reduced speech vectors; and (i) performing speech recognition on said noise-reduced speech vectors.