METHOD FOR IMPROVING SPEECH SIGNAL NON-LINEAR OVERWEIGHTING GAIN IN WAVELET PACKET TRANSFORM DOMAIN

摘要

The present invention relates to speech enhancement accomplished by applying an overweighting gain of a nonlinear structure in a wavelet packet transform domain or a Fourier transform domain. The present invention relates to a method for improving quality of speech signals, which can be applied in a variety of noise-level conditions using noise estimation of the least-square line method and a modified spectral subtraction method having a nonlinear overweighting gain for each sub-band. According to the method for improving quality of speech of the present invention, it is effective in that quality of speech can be further effectively improved in a variety of noise-level conditions. Particularly, according to the present invention, generation of musical tones can be efficiently suppressed, and intelligibility of speech is reliably guaranteed in the improved speech.