Patent ID: 8438026
Filing Date: 2013-05-07
Classification: G10L

Abstract:
1. A method for generating training data for an automatic speech recognizer operating at a first sampling frequency, comprising: deriving spectral characteristics from audio data sampled at a second frequency lower than the first sampling frequency; extending a bandwidth of the spectral characteristics by retrieving bandwidth extending information from a codebook so that the audio data sampled at the second frequency is compatible with the automatic speech recognizer operating at the first sampling frequency; and processing the bandwidth extended spectral characteristics to give the required training data, wherein extending the bandwidth includes augmenting the spectral characteristics of the audio data sampled at the second frequency with a set of spectral characteristics of audio data sampled at the first sampling frequency obtained from the codebook, wherein each entry in the codebook is generated by: deriving a first set of spectral characteristics from audio data sampled at the first sampling frequency; performing a sampling rate transformation on the audio data to the second frequency and deriving a corresponding second set of spectral characteristics; and generating a codebook entry comprising information from the second set of spectral characteristics, together with additional bandwidth extending information extracted from the first set of spectral characteristics.