Method and apparatus for reducing random, continuous non-stationary noise in audio signals

A method of reducing random, continuous, non-stationary noise in a noisy audio signal, comprising:

• establishing a dynamic noise component from the noisy audio signal;
• establishing a dynamic signal component from the noisy audio signal;
• dynamically determining a filter function in response to the dynamic signal component and the dynamic noise component;
• dynamically limiting the filter function in response to the dynamic noise component;
• and
• applying the filter function to the noisy audio signal
• and further comprising the steps of:
• producing a noise estimate, which describes the time-dependent change of the dynamic noise component,
• determining an unrestricted filter function HG(m,l) from the noise estimate;
• producing a restriction function γSF(m,l) from the noise estimate;
• establishing a restricted filter function HGdyn(m,l);
• setting the restricted filter function HGdyn(m,l) equal to the greater of the unrestricted filter function HG(m,l) or the restriction function γSF(m,l);
• and
• filtering the noisy audio signal with the restricted filter function HGdyn(m,l);
• wherein m is a discrete spectral frequency or equivalent thereof, and l is a discrete time of a signal block in the case of block-wise signal processing.