Patent ID: 8583426

Claim:
A method for enhancing speech components of an audio signal composed of speech and noise components, comprising: changing the audio signal from a time domain representation to a plurality of subbands in a frequency domain representation producing K multiple subband signals, Y k (m), k=1, . . . , K, m=0, 1, . . . , ∞, where k is the subband number, and m is a time index of each subband signal, processing subbands of the audio signal, wherein a subband has a gain, said processing including controlling the gain of the audio signal in ones of said subbands, wherein the gain in a subband is controlled by an additive/subtractive or multiplicative combination of a) reducing the gain of the audio signal in a subband as an estimate of the level of noise components in the subband increases, wherein the estimate of the level of noise components in the subband is determined when speech is not present, and b) increasing the gain of the audio signal in one or more subbands important to the intelligibility of speech in accordance with a voice clarity process when speech components are present in the audio signal, the gain increase being reduced in accordance with time smoothing upon a transition from the presence of speech components to speech components not being present, the processes a) and b) each being performed according to a set of parameters continuously updated for each time index m, said parameters being dependent only on their respective prior value at time index (m−1), characteristics of the subband at time index m, and a set of predetermined constants, changing the processed subband audio signal from the frequency domain to the time domain to provide an audio signal in which speech components are enhanced, and wherein the process is performed by a special purpose computer performing the steps of the process or by a general purpose computer programmed to perform the steps of the process.