Voice Recognition in Noisy Environment Using Array of Microphone

摘要

The performance of voice recognition reduces significantly in noisy environments, where the voice signals are distorted severely by addition of noise signal and reverberations. In such environments we can use array of microphone and use beamforming techniques to reduce the effect of noise signals. Presently, microphone-array-based voice recognition is done in two independent stages: first beamforming by array processing and then sending it for recognition. To reduce the effect of noise that is to reduce the distortion in voice waveform array processing algorithm is designed to enhance the signal before feature extraction and recognition. In Beamforming technique an array of sensors, in our case sensors are microphones, is used so that maximum reception can be achieved in a desired specified direction that is in the presence of noise, by the use of estimation of direction algorithm while signals from undesired direction are rejected though they are of same frequency. This is done by using delay and sum method in which the outputs from an array of microphones are delayed by some time so when they are added together, a particular part of the sound field is amplified over other undesired or interfering sources. Then the focussed voice wave is sent to voice recognition algorithm. Correlation algorithm is used for the voice recognition. The algorithm is based on the fact correlation graph between same signal is symmetric and value of correlation is maximum. The system development for this voice recognizer will be done using MATLAB for this project. Using MATLAB a GUI is created which has different function buttons to perform different tasks.