Automatic background noise estimator for a noise suppression system

An improved background noise estimator adapted for use with a noise suppression system wherein the background noise from a noisy pre-processed input signal is attenuated by spectral gain modification to produce a noise-suppressed post-processed output signal, said background noise estimator comprising:

• storage means for storing an estimate of the background noise energy of the pre-processed signal in each of a plurality of selected frequency bands as per-channel noise estimates, and for continuously providing an estimate of the background noise power spectral density of the pre-processed signal to said noise suppression system;
• valley detection means for periodically detecting the minima of an overall estimate of the energy of said post-processed signal in each of a plurality of selected frequency bands, thereby generating a valley detect signal;
• and
• signal controlling means coupled to said storage means and controlled by said valley detect signal for providing new background noise estimates to said storage means only during said minima.

The method of estimating background noise in a noise suppression system, wherein the background noise from a noisy pre-processed input signal is attenuated by spectral gain modification to produce a noise-suppressed post-processed output signal, comprising the steps of:

• periodically detecting the minima of the post-processed signal energy;
• providing a noise detection signal only when said minima is detected;
• and
• generating and storing an estimate of the background noise power spectral density of the pre-processed signal only during the presence of said noise detection signal.

The method of estimating background noise in a noise suppression system, wherein the background noise from a noisy pre-processed input signal is attenuated by spectral gain modification to produce a noise-suppressed post-processed output signal, comprising the steps of:

• periodically detecting the minima of an overall estimate of the energy of the post-processed signal in each of a plurality of selected frequency bands;
• providing a positive valley detect signal only when said minima is detected;
• and
• storing an estimate of the energy of the pre-processed signal in each of a plurality of selected frequency bands only during the presence of said positive valley detect signal.