Reduction of interference in knee sound signals by adaptive filtering

The effects of interfering signals in the knee and the need for an adaptive filtering scheme for knee-sound estimation are briefly discussed. A least-mean-squares algorithm has been used for adaptive cancellation of interfering signals in knee sounds. In the implementation, a two-stage adaptive scheme is used to cancel both muscle contraction and tremor artifacts. Experiments show that with the proposed filtering scheme the interfering signals are significantly reduced, while retaining the desired features of the knee-sound signals. This will subsequently allow accurate quantitative analysis and objective diagnosis of cartilage pathology