Two compartment fusion system designed for physiological state monitoring
Han C. Ryoo, Hongyu Sun, Leonid Hrebien · 2005
A two-compartment fusion system designed to reduce high rates of false alarm (FAR) in single channel monitoring systems was tested with physiological data from pilots exposed to high +Gz forces on a human centrifuge. The first compartment expands input signals into the time-frequency domain, where transient changes are captured by wavelet coefficients in frequency ranges of interest. The second compartment optimally combines local decisions of various statistics using a unifying operation rule regardless of individual subject physiology and channel features. Three channels were used to measure respiration, blood pressure, and electroencephalogram under various high performance aircraft maneuver profiles: rapid onset run (ROR) to a fixed plateau, gradual onset run (GOR) at 0.1 Gz per second onset, and simulated aerial combat (SACM) profiles. Pilots sometimes perform anti-G straining maneuvers (AGSM) against the blood pressure drop at head level for greater tolerance. Signals were simultaneously processed to decide the presence of such AGSM. Significant reductions of FAR when detecting AGSM by signal fusion were achieved in our experiment (10/spl sim/38% during ROR/GOR, 25/spl sim/35% during SACM, and 21/spl sim/36% overall), when compared to single channel monitoring. This implies that our approach is very promising and system performance can be enhanced even with poor quality signals.