Development of a Non-Linear Smoothing Filter for the Processing of Eye-Movement Signals.

摘要

The analysis of eye-movement (EM) signals poses problems for the designer of smoothing filters since many of the interesting types of EMs are bimodal. Conventional linear, low-pass filters (both finite impulse response (FIR) and infinite impulse response (IIR) types) smear the boundaries between the fast-and slow-phases of nystagmus and the fixation and fast components of saccadic EMs. We have adapted a nonlinear smoothing filter (originally designed to optimise edge preservation in image processing applications) for the smoothing of EM signals. This filter is called Predictive FIR-Median Hybrid (PFMH) filter. The PFMH filter operates on a moving window of data samples centered at the current point of interest. By properly choosing the length and structure of the FIR subfilters, a PFMH filter can be designed to smooth a bimodal EM signal without blurring the boundaries between the two signal components.