Systems and Methods of Echo & Noise Cancellation in Voice Communication

摘要

In an example, time and frequency domain speech enhancement is implemented on a platform having a programmable device, such a PC or a smartphone running an OS. Echo cancellation is done first in time domain to cancel a dominant portion of the echo. Residual echo is cancelled jointly with noise reduction during a subsequent frequency domain stage. The time domain block uses a dual band, shorter length Adaptive Filter for faster convergence. Non-linear residual echo is cancelled based on an echo estimate and an error signal from the adaptive filters. A controller locates regions that had residual echo suppressed and which do not have speech and injects comfort noise. The controller can be full-duplex and operate non-linearly. An AGC selectively amplifies the frequency bins, based on the Gain function used by the residual echo and noise canceller.

主权项

1. A machine-implemented method of echo cancellation in a full duplex voice communication system, comprising:
performing acoustic echo cancellation on a near-end signal using a short time domain adaptive filter, to produce a filtered near-end signal that may have non-linear residual echo and noise; tracking, in the frequency domain, the non-linear residual echo in the filtered near-end signal to output an error signal; producing an estimate of a portion of the filtered near-end signal to be removed, as a combination of the non-linear residual echo, and noise; imposing a limitation on the estimate based on a moving average of the error signal; controlling gains associated with a plurality of frequency bins in a Frequency domain Automatic Gain Controller (FAGC), based on the limited estimate, thereby suppressing the estimated portion of the filtered near-end signal to be removed; and refining respective gains associated with the plurality of frequency bins of the FAGC.