A Research Of The Chinese Speech Recognition Based On The GA-BP Model

Speech recognition is a complex nonlinear process. Up to now, most speech recognition method based on conventional linear system theory, such as Hidden Markov Model (HMM) is hard to have a breakthrough. Recently, with the development of nonlinear-system theories about artificial neural networks (ANN), the recognition method based on ANN became the focus of the research.The paper mainly stresses on theoretical studies and applications in speech recognition of feedforward neural networks (BP networks).1. How to extract speech-feature efficientlyAbout this queston, this paper firstly researches how to efficiently detect the endpoint of speech signal. In addition, the paper analyzed the advantages and disadvantages of traditional detection method and their improved method. Then, the paper discusses cepstral features based on linear predictive and non-linear Mel scal, and induces LPCC and MFCC extraction algorithm and their one rank coefficient is also presented.2. About the application of BP neural networks in speech recognitionThis paper studies the design principle of BP neural network and analyzes the advantages and disadvantages of traditional BP algorithm and its improved method. Then, the paper improved traditional method with dynamic learning rate to train network.3. About the application of Genetic Algorithm in neural networkThis paper mainly studies on those problems that optimizing neural networks topology structure and weights with genetic algorithm. In this part, the paper also introduces the theory of genetic algorithm and the progress of optimizing neural networks topology structure and weights with them. What's more, the paper also analyzes the affect of genetic algorithm's mainly parameters on optimizing performance.In the end, this paper designs a Chinese speech recognition model based on genetic algorithm and BP neural network. The design and exploitation of software for experiments is also completed based on VC++ 6.0. Experiment result show better recognition performance and particular application advantages are achieved by the method for speech recognition based on GA-BP. Especially for the Isolated Word Recognition (IWR), the recognition accuracy is better than 95%.