Double Talk Detection in hands-free mobile communication- A comprehensive survey

Abstract

In modern teleconferencing systems, echo cancellation is a mandatory requirement. Echoes arise in Loudspeaker Enclosure Microphone devices because of coupling between loudspeaker and microphone signals. To remove these unwanted echoes from microphone signals, Acoustic Echo Cancellers are used. Several techniques exist for acoustic echo cancellation. Acoustic echo cancelling an adaptive FIR/IIR filter can predict the path of echo and cancel it. The adaptive algorithms give good performance when only the far-end signal is present. But when the near-end signal is present, the adaptive filter tends to diverge. Such a situation creates a double talk scenario. The filter adaptation must be prevented during the double talk period. Accurate detection of double talk is quite difficult and computationally complex. Hence the algorithms for detecting Double Talk are not easy to implement. Increased detection accuracy is achieved at the cost of computational complexity. Further, it is desired to cancel out the far end echo signal, thus giving a good quality of near-end speech signal as output. Here, we provide a detailed study of the different algorithms existing for double talk detection, and future direction of research in the field of double talk detection is proposed.