Adaptive compression of teleconference sequences using the LMS Algorithm

The Least Mean Squares (LMS) adaptive algorithm is applied to the problem of reducing the mean square power of the information sequence required for transmission of video or teleconferencing image sequences. The results of processing actual teleconferencing sequences are presented and compared with the results of using a fixed coefficient predictive algorithm. Operating on actual teleconferencing sequences averaging 2% - 12% moving area, the LMS adaptive filter is shown to provide approximately 1-4 dB reduction in transmitted sequence power when compared to a fixed coefficient filter. Further, the performance of the LMS adaptive system is shown to be quite insensitive to the value of the feedback gain parameter, α, for a wide range of α. This allows the user to achieve a substantial performance gain (compared to the fixed coefficient system) without encountering problems of adaptive filter stability.