Noise Reduction on Speech Using Sequential Spectrum Detection Based on Modified DFT Pair

A single-channel method for noise reduction on speech is proposed in this paper. A noise added speech is decomposed into frequency signals using the modified DFT. From each frequency signal, signal and noise elements are sequentially detected and then noise subtraction is performed by subtracting the noise element from the signal one. Detectors for the signal and noise elements are implemented by simple averaging circuits. However, the noise level detector needs a coefficient to compensate differences between the detected levels and proper ones. In this paper, we introduce automatic setting of the coefficient into the proposed method. The effectiveness of the proposed noise reduction method is evaluated in computer simulations of speech noise reduction and subjective evaluations using processed signals.