Many speech enhancement systems attempt to reduce the background noise in a noisy speech signal.
Although the noise can be efficiently reduced, the enhanced speech signal suffers from two major problems,
known as speech distortion and residual noise. In order to suppress more amount of residual noise, the noisy
speech should be reduced more. It results in the higher the speech distortion. The speech quality is therefore
deteriorated. On the contrary, the slighter the noisy speech is reduced, the slighter the speech distortion is.
This fact results in the more the residual noise to be retained. Accordingly, how to make tradeoff between
the reduction of residual noise and the reduction of speech distortion is still a major problem for designing a
speech enhancement system. In this project, we aims at reducing the residual noise and reconstructing
distorted speech signal for a noisy signal by a three-stage speech enhancement system. The first stage is
perceptual-based speech enhancement algorithm. This algorithm is beneficial to suppress background noise
while speech components can be preserved. At the second stage, musical residual noise is detected and
suppressed. We will investigate the variation properties of residual noise in enhanced speech denoised by
the first stage. Analyzing the motion vectors of a spectral bin over neighbor subbands and over successive
frames should be performed. Hence, the musical tone is then detected and suppressed adequately to avoid
another musical tone arising when a musical tone is suppressed. In order to improve speech quality, the third
stage is employed to reconstruct the harmonics which were destroyed by infecting noise or removed by the
speech enhancement algorithm given in the first stage. Consequently, the denoised speech can be refined by
both reconstructing the harmonics of vowels with little energy which were removed by a speech
enhancement system or destroyed by corrupting noise, and by suppressing the musical residual noise in a
denoised speech signal. It enables the processed speech to sound comfortable.