Patent ID: 11942104
Assignee: TEAM VIEWER GERMANY GMBH
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 10:
11. A method for enhancing an audio signal in a full duplex communication system, the method comprising the following steps:
a) receiving a far end audio signal from a communication input;
b) forwarding the far end audio signal to an audio speaker;
c) receiving a near end audio signal from a microphone;
d) performing an echo reduction within a signal enhancement chain on the received near end audio signal;
e) forwarding the near end audio signal after the echo reduction to a communication output;
f) determining whether a residual echo still exists in the near end audio signal after the echo reduction, and
g) if the existence of residual echo is determined:
attenuating the near end audio signal;
deactivating its forwarding to the communication output and/or
adjusting at least one parameter of the signal enhancement chain,

wherein the step for determining the existence of residual echo includes a residual echo existence estimation which compares the near end audio signal and the far end audio signal in a frequency domain and statistically analyzes the outcome,
wherein estimating the existence of residual echo comprises transferring time slots of the near end audio signal and the far end audio signal into the frequency domain thereby providing a plurality of time step dependent near end spectra and a plurality of time step dependent far end spectra,
wherein each time step dependent near end spectrum is compared to a plurality of time delayed versions of the time step dependent far end spectra by calculating a distance value d between the time step dependent near end spectrum and each of the plurality of time step dependent far end spectra, and
wherein calculating the distance value d includes using a set of preset mapping templates Ti which mapping templates modify the near end spectra and/or the far end spectra in order to take into account for prototypic realistic acoustic transfer functions.