| 摘要 |
The present invention relates to a method and device at stereo acoustic echo cancellation. Acoustic echo cancellation in stereo is considerably more difficult than echo cancellation in mono, due to strong correlation between the stereo channels. This invention is based on utilization of a perceptual audio coder to reduce the correlation between the stereo channels, without introducing audible distorsion. This will result in that the stereo canceller converges towards the correct echo paths and therefore gives a more stable echo cancellation which is not dependent on the transmission room (far-end). The core of the invention is that one can reduce the correlation in excess of that which is made by the audio coder, by modifying its decoder. Extra, uncorrelated (between the channels) noise is added (in the decoder) to such an extent that it is not audible, by information provided from the coder being used in combination with an estimated perceptual masking threshold. The solution consequently is flexible and does not require that the coding standard which is used is changed in any way. Only a small number of operations need to be included in the decoder. |
