Abstract
Focusing on the development of new technologies of information, research in the speech communication field is an activity in full expansion. Several disciplines and skills interact in order to improve performance of HumanMachine Communication Systems (HMC). In order to increase the performance of these systems, various techniques, including Hidden Markov Models (HMM) and Neural Network (NN), are implemented.
In this paper, we advance a new approach for modelling of acoustic units and a new method for speech recognition, especially recognition of Arabic word, adapting to this new type of modelling based on Wavelet Network (WN). The new recognition system is a hybrid classifier. It is based on NN as a general model and the wavelets assume the role of activation function.
Our approach of speech recognition is divided into two parts: training, and recognition phases. The training stage is based on audio corpus. After converting all training signals from original format to a specific parameterisation, each acoustic vector will be modelled by WN. These vectors will refine and cover all signal properties in one model. It consists in generating a WN for every training signal. The recognition phase is divided into three steps. The first is to extract features from the input vector to be recognized. The second is to estimate all resulting vectors from trainingWN. The third is to evaluate the distance between the vector to be recognized and the reconstructed vectors.
The obtained results shows that our system, based on WN, is very competitive compared to systems based on HMM.