AUTOMATIC SECURITY SYSTEM AND METHOD IN ELEVATOR USING VOICE RECOGNITION

摘要

PURPOSE: An automatic security system within an elevator using the voice recognition for preventing crime within the improvement of the voice recognition rate is provided to remove the sound of a speaker and the noise of the elevator for a microphone of the elevator. CONSTITUTION: An FFT(Fast Fourier Transform) performs the FFT of a digital signal of a microphone. An FFT performs the FFT of the digital signal of a line input. A reference signal estimator(21b) determines the update of coefficients of an adaptive filter(21a). The adaptive filter filters the line input signal. A noise spectrum estimator estimates the spectrum of the noise in the residual reference signal removed microphone input signal. A noise spectrum removes the spectrum of the noise.