Variability in Foot-Worn Sensor Placement for Activity Recognition

On-shoe acceleration and orientation sensors have revealed as a potentially powerful means for capturing aspects of human gait. The placement of sensors however has been done intuitively and mostly without quantitative evaluation of sensor positioning. Based on recorded signals of the five placement options sole, heel, toe-cap, instep and ankle we built SVM classifiers using orientation based features and evaluate their performance on three activity classes level walking, going upstairs and going downstairs. Finally we present an approach to a placement-invariant classification model and discuss the benefit for a bipedal sensing setup.