Filtering

Two filtering algorithms have been developed to distinguish undesired motion from intended motion:

1.      Tremor – Weighted-frequency Fourier Linear Combiner (WFLC)

2.      Non-tremulous errors – Cascaded neural networks with extended Kalman filtering

 

Weighted-frequency Fourier Linear Combiner (WFLC)

The WFLC is a nonlinear adaptive noise canceling algorithm that models the tremor as a sinusoid and tracks its modulation in frequency, phase, and amplitude. In preliminary experiments with a 1-dof instrument, active canceling of recorded tremor by a system based on the WFLC demonstrated an average rms amplitude reduction of 69%. Fig. 1 presents typical results from these experiments. The algorithm has also been used for canceling of pathological tremor in assistive computer interfaces.

Fig. 1. Sample results from active compensation of recorded physiological tremor in a 1-dof 

instrument using tremor estimation via the WFLC algorithm. The hand motion used as input 

in these experiments was recorded from vitreoretinal surgeons and reproduced using a 

voice coil actuator. The black line represents the reproduced motion as measured at the 

instrument tip in the absence of compensation. The blue line represents the compensated 

tip motion for the same input data.  

Publications:

1.    Adaptive canceling of physiological tremor for improved precision in microsurgery
C. Riviere, R.S. Rader, and N.V. Thakor
IEEE Transactions on Biomedical Engineering, Vol. 45, No. 7, July, 1998, pp. 839 - 846. [Abstract]
Download: pdf [193 KB] copyrighted

2.     Modeling and canceling tremor in human-machine interfaces
C. Riviere and N.V. Thakor
IEEE Engineering in Medicine and Biology Magazine, Vol. 15, No. 3, June, 1996, pp. 29 - 36. [Abstract]
Download: pdf [1240 KB] copyrighted

 

 

Return to Research Activity

Return to Micron 1

Return to Filtering 2